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Equipment Discussions >> Refractors

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jrbarnett
Eyepiece Hooligan
*****

Reged: 02/28/06

Loc: Petaluma, CA
Overdue First Light: Astrotelescopes 152 f/5.9
      #5469716 - 10/14/12 12:25 PM

A colorful scope deserves a colorful first light report, so here goes.

Color. Of the inauthentic variety. Oodles and oodles, even at very, *VERY* low magnifications. In the 30mm Astro-Tech Titan II and 27m Panoptic during alignment of the mount, the first and second magnitude alignment stars showed pronounced blue-violet haloing. It was unmistakable.

Whew. Now that the color question is out there, I feel much better. Don't you? So, putting aside the fact that this scope has precisely the plentiful amount of false color that you should expect a 6" f/5.9 crown & flint doublet to have, how was it?

Not bad at all, actually. The scope produced lovely highly contextual views of late summer/early fall classics. Even with moderate magnification 64x; 1.3 degree FOV with a 14mm Series 4000 UWA). The eastern, then western Veil segments were nice with a 2" O-III in the 27mm Panoptic and 30mm Titan II ED were nice. Bright, large globulars like M13 and M22 were neat; reasonably resolved around the edges, and peppered through their cores, even at low magnification, with a lot of spangled sky surrounding.

The Double Cluster was nicely framed as were the Pleiades, though I felt that the Double Cluster wasn't showing as many stars as it should (i.e., looked surprisingly under-resolved for the aperture.

On the optical quality front, the optic is surprisingly good for such a large, cheap doublet. Intra-and-extra-focal diffraction patterns were similar but not quite identical, but nothing to raise eyebrows.

Being a glutton for punishment, I ran the scope up to 224x to see how it handled higher magnifications. I'd be remiss not to mention the false color again in this context. Rasalgethi was fiery orange brand (surrounded by a HUGE violet halo) with a tiny cerulean follower, surrounded by a modest violet halo, in tow. I'd be lying if I didn't say the color was distracting. On the other hand, it was a nice wide split.

*bugle call*

Calvary to the rescue! Just when we thought our gooses were cooked in a briny stew of purplescence, the US Calvary comes charging over the hill, Old Glory flowing overhead, and the purple bandits scatter (somewhat) on the winds. Okay, not the calvary, but instead my vintage Sirius Optics MV-20 minus violet filter. It really did save the day on double stars at high magnification with this scope. Rasalgethi, for example, was cleaned up nicely to the point where the errant color was reduced by ~80% (SOTP) and the split was very aesthetic, with the primary and secondary showing their true colors much better. I would not bother to use this scope at >100x without some kind of violet blocker in place, at least on bright targets.

So, where do I think this scope comes out on the value front? That's a toughie. The price isn't huge...for a well-built, large refractor. The price is huge, however, relative to some alternatives to be discussed in a moment. The scope is massive. Longish, heavy and not well-balanced (it's needlessly front heavy; it's not a triplet). The dew shade could be reduced in weight by going with a thinner gauge's material, and that would help a bit. The Stellarvue version of the new Chinese R&P focuser (also sold on APM scopes and a few others, now) was good, though extended use of it and the Long Perng Crayford, same night, I have to give the nod to the Long Perng as being a bit smoother, and lower in shift than the Stellarvue.

Were you to come to me and say "Jim, I'd like the best deal money can buy in a 6" OTA, and I want to spend $1000 or less" I would not recommend this scope. Instead I'd steer you quickly to the $400 Celestron C6 OTA. Sure, you get a big CO and give up "rich field" observing, but in every other respect I think the C6 handily surpasses the Astrotelescopes big achro. Here's a dirty little secret - the C6's images are actually a little brighter and on clusters and at like magnification (~88x in each) it goes a little deeper to boot. The Ceelstron f/6.3 FF/FR even gets you back some of the contextual feel of the big achro, too.

So, I'd say overall the scope is neat for the right buyer - someone looking for a modern day equivalent to a Jaegers 6" RFT achro or similar. But other than that niche group, I think most buyers would be better served with something else.

Regards,

Jim

Edited by jrbarnett (10/14/12 02:12 PM)


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junomike
Carpal Tunnel
*****

Reged: 09/07/09

Loc: Ontario
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: jrbarnett]
      #5469770 - 10/14/12 01:07 PM

Jim, That's one of the most truthful, unbiased reviews I've ever read!
I wish more people could see through the NCF (New Scope Filter) which sometimes hides or blocks out the true facts.

Seriously, this review needs to be placed under the "Reviews" section of CN so others can easily find It.

Good Job!

Mike


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stevew
Now I've done it


Reged: 03/03/06

Loc: British Columbia Canada
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: jrbarnett]
      #5469871 - 10/14/12 02:09 PM

Quote:

Here's a dirty little secret - the C6's images are actually a little brighter and on clusters and at like magnification (~88x in each) it goes a little deeper to boot.

Regards,

Jim



Very curious.....


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johnC
member
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Reged: 08/24/06

Loc: Hucknall Nottingham UK
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: stevew]
      #5469898 - 10/14/12 02:29 PM

Certainly not the findings of the ones sold here??

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dakota
sage
*****

Reged: 12/11/11

Loc: SD (God's Country)
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: johnC]
      #5469923 - 10/14/12 02:52 PM

I certainly disagree with his evaluation. Of course keep in mind that I have never looked thru a Tec, TAK, or AP. Nothing against Jim but I find the scope worth every penny.

Of course I am the type of person that doesn't spend all of my time evaluating things, I would rather be out enjoying what I have and using it for it's intended purposes.


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stevew
Now I've done it


Reged: 03/03/06

Loc: British Columbia Canada
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: johnC]
      #5469990 - 10/14/12 03:16 PM

As a past owner of a Jaegers 6 inch F-5, and a current owner of an Antares 152 F-6.5, I can certainly attest to the wonderful views that a large RFT refactor can provide.
Yes, these scopes are specialized instruments designed for rich field viewing under dark skies. As long as the prospective buyer understands that he is not purchasing a planetary telescope I would think that the Astrotelescopes 152 would be a good buy. Never the less it seems that at some point we all still aim these rich field instruments towards the planets.
I think it's just human nature. Like wanting your F-10 SCT to be a rich field instrument.
Most of the time it's disappointing. In my own 6 inch RFT the spherical aberration starts to creep in around 100X.
Still when they are used for what they are designed to do, they can be wonderful instruments.
Good report Jim, as usual.

Steve


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jrbarnett
Eyepiece Hooligan
*****

Reged: 02/28/06

Loc: Petaluma, CA
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: stevew]
      #5470011 - 10/14/12 03:27 PM

Dunno, Steve. Perhaps the large swath of defocused portions of the visual spectrum affect the "tightness" of the in-focus stars. Perhaps the optics are a bit rough. Perhaps there's some attenuation happening. Perhaps the baffling isn't as effective as it should be. Lots of possibilities. It's not a bad scope. It's actually a very entertaining scope, but there are several liabilities that come with it that I suspect would irritate many users.

From my perspective there were no surprises. I expected false color, and received it, expected mass and length, and received them, and expected decent optical and mechanical quality, and received them. On the value front, though, unless someone is Hellbent on having a 6" fast achromat, there are other 5 to 8 inchers that would likely be easier to live with and more well-rounded, for the same or less money.

Regards,

Jim


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dakota
sage
*****

Reged: 12/11/11

Loc: SD (God's Country)
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: jrbarnett]
      #5470087 - 10/14/12 04:08 PM

So what do you say to the reviews by Warren Maguire on the CT152 and Larry Carlino on the AT152? Are you saying they are wrong? As usual with your review and the other 2 reviews they are merely self opinions which don't necessarily reflect the views of others.

Yes the dew shield is heavy, but a few strips of felt took care of it sliding at zenith. I would rather have a heavy duty dew shield than some piece of plastic. With regard to your views on the focuser, they are your views and not mine. I have 2 of the 2.5 Stellarvue focusers and in reality I find the one on the AT152 somewhat better than the one on my SV110.

Maybe you just received a 'bad' unit of the AT152. Perhaps you should return it for exchange or your money back.


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mgwhittle
Pooh-Bah
*****

Reged: 08/24/11

Loc: Chattanooga, TN
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: jrbarnett]
      #5470102 - 10/14/12 04:17 PM

Thanks for this review, Jim. I came very close to buying one, even started a thread about it. I began to suspect that there was more color than owners were talking about, the "new scope filter" as Mike mentioned, and therefore decided to pass. After reading this review, I'm glad I didn't buy one. I agree that the AT152 plays to a specific audience, many which are happy.

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t.r.
Post Laureate
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Reged: 02/14/08

Loc: Upstate NY
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: mgwhittle]
      #5470126 - 10/14/12 04:33 PM

Jim, don't tell me you didn't look at Jupiter or the moon with this scope?!?

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jrbarnett
Eyepiece Hooligan
*****

Reged: 02/28/06

Loc: Petaluma, CA
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: dakota]
      #5470207 - 10/14/12 05:24 PM

"Are you saying they are wrong?"

Yes, actually. There was no mistaking the chromatic aberration. It has loads and loads. Of course, it's nothing that a cataract or two couldn't mask.

Given my experience with scopes, I can assure you that there's nothing "wrong with mine". I did star test it. I used it at high magnification, with and without filters. It performs exactly as a 6" f/5.9 achromatic doublet ought to perform. Given that I received exactly what I expected, and the scope is in perfect working order, in conformance with the laws of physics even, why would I return it for a refund?

With respect to the dew shade, there's a big difference between good design and plastic. I didn't say plastic. Take a look at any high end refractor. The dew shade material is thinner walled than the OTA material, and typically of the same material. That's the way this one should have been done, too, to avoid needless balance issues. Look at the image below showing how far back in the rings the OTA sits. Compare that to pictures of other OTAs on their mounts.

On the other hand, I typically don't take deficiencies my gear suffers personally.

Regards,

Jim

Edited by jrbarnett (10/14/12 05:30 PM)


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jrbarnett
Eyepiece Hooligan
*****

Reged: 02/28/06

Loc: Petaluma, CA
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: jrbarnett]
      #5470210 - 10/14/12 05:27 PM

Now, mit picturen!







Regards,

Jim


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jrbarnett
Eyepiece Hooligan
*****

Reged: 02/28/06

Loc: Petaluma, CA
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: jrbarnett]
      #5470227 - 10/14/12 05:34 PM

And I have to post these...

Planewave 12.5" Corrected D-K on AP-900.







- Jim


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astrogeezer41
super member
*****

Reged: 08/27/10

Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: jrbarnett]
      #5470242 - 10/14/12 05:41 PM

Thanks for the informative review, Jim. I had been looking forward to it. It seems to me that you are just telling it as it is. - Robert

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jrbarnett
Eyepiece Hooligan
*****

Reged: 02/28/06

Loc: Petaluma, CA
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: t.r.]
      #5470243 - 10/14/12 05:42 PM

Nope. By the time Jupiter was up above the eastern treeline, I'd already bagged the AT152 in favor of a different OTA for the remainder of the session. Honestly, based on what I and the other two observers experienced on Vega and even Magnitude 2.9, ruddy, Rasalgethi, I'd pretty much decided that I would be sticking to DSOs with this puppy. It's going to be my Giant Monocular.

I think I'll order a 40mm ES 68, and JB weld it into a diagonal, and then the diagonal into the focuser. That way, no one else accidentally hurts themselves on a bright target.

- Jim


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johnnyha
Postmaster
*****

Reged: 11/12/06

Loc: Sherman Oaks, CA
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: jrbarnett]
      #5470254 - 10/14/12 05:48 PM

Thanks for the report Jim. I was also thinking some of the differences with the C6 at equal magnification could be explained by f5.9 v. f8.

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jrbarnett
Eyepiece Hooligan
*****

Reged: 02/28/06

Loc: Petaluma, CA
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: johnnyha]
      #5470259 - 10/14/12 05:52 PM

f/10 actually, but f/6.3 with the FF/FR in the optical train.

Regards,

Jim


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johnnyha
Postmaster
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Reged: 11/12/06

Loc: Sherman Oaks, CA
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: jrbarnett]
      #5470264 - 10/14/12 05:56 PM

Oh, I though you were talking about the refractor!

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Mike4242
Pooh-Bah


Reged: 11/02/11

Loc: Memphis, TN
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: jrbarnett]
      #5470267 - 10/14/12 05:56 PM

I think this is a fair review based on what I've seen with my AR152. The AT-152 definitely balances farther back in the saddle than the AR152 -- that must be one heavy dew shield.

Quote:

Yes, actually. There was no mistaking the chromatic aberration. It has loads and loads. Of course, it's nothing that a cataract or two couldn't mask.




I've noticed the same in the AR152. I even noticed CA on 3.5 magnitude Sheliak, B Lyr. The AT-152 supposedly has better color correction than the AR152 though.

I think as long as the buyer knows what they're getting with one of these fast achromats, there shouldn't be too much disappointment. However, I could see where an unwary buyer could plunge into one these 6" achromats, lured by the attractive price and aperture, only to be sorely disappointed.

I'm personally not bothered too much by the amount of CA in these scopes, I tend to become so immersed in the object of study that I don't even notice the CA. However, the CA tolerance varies from person to person and for someone obsessive about their gear, it is probably very difficult to look past.


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stevew
Now I've done it


Reged: 03/03/06

Loc: British Columbia Canada
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: jrbarnett]
      #5470295 - 10/14/12 06:05 PM Attachment (93 downloads)

I think the Astrotelescope 152 is a funky looking scope.
Spending an evening with a "giant monocular" can be a wonderful evening in my books.
I think of my Antares 152 the same way.

Steve


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jrbarnett
Eyepiece Hooligan
*****

Reged: 02/28/06

Loc: Petaluma, CA
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Mike4242]
      #5470304 - 10/14/12 06:15 PM

"I'm personally not bothered too much by the amount of CA in these scopes,..."

Ditto, Mike.

Where things get hairy, though is when someone goes and buys one on the basis of "very little false color" claims, and finds otherwise after the fact of purchase.

I'll put it this way. It's highly unlikely that someone buying a scope, expecting it to have lots of false color, but who instead finds it to have less than expected, will feel cheated. On the other hand, there are probably quite a few who, if they bought a scope with the expectation of minimal false color, but found instead that it has quite a lot, would feel somewhat misled.

One last point, while individuals' ability to recognize false color may indeed be different, I don't think the presence or absence of false color falls in the realm of "opinion". Optics can be analyzed and the degree of defocus of unfocused wavelengths relative to in-focus wavelengths can be measured. The larger the amount of defocus (in distance terms) of any visual wavelength, the more chromatic aberration the optic factually has, whether or not a given user recognizes it.

The Great Lick (36" Clark achromat in San Jose, CA) has certain visual wavlengths several *INCHES* out of focus when the image appears to be focused. Obviously this little scope wasn't that bad, but I have no doubt that if Vlad had the prescription for the optic, he could tell us exactly which wavelengths were defocused and by how much when the image is in-focus.

Regards,

Jim


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jrbarnett
Eyepiece Hooligan
*****

Reged: 02/28/06

Loc: Petaluma, CA
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: stevew]
      #5470312 - 10/14/12 06:19 PM

Yep.

I'm toying with the idea of running the 2013 Messier Marathon with mine. Talk about "fish in a barrel". With a 40mm 68 degree eyepiece, I'd have 3 degrees of TFOV and 6-inches of light gathering and resolution.

The 6" f/5.9 is dead! Long live the 6" f/5.9!

- Jim


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dakota
sage
*****

Reged: 12/11/11

Loc: SD (God's Country)
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: jrbarnett]
      #5470669 - 10/14/12 10:13 PM

I don't recall accusing you of saying the dew shield was plastic. I don't recall the other reviewers saying the was no CA. Seems like you are the one twisting the facts mister.

Reread your initial review. Came out pretty strong with negatives. I didn't take anything personally. So no need to throw that barb into the discussion.

I have no problem with the balance. My lowly CG-5 handles this scope quite well. Just balance it properly and one is all set.

Again, this is your opinion which you are entitled to. So don't take it personally when someone doesn't agree with you.


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MikeBOKC
Post Laureate
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Reged: 05/10/10

Loc: Oklahoma City, OK
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: jrbarnett]
      #5470700 - 10/14/12 10:29 PM

I will say this -- those husky 6 inch achros LOOK like a telescope ought to!

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jrbarnett
Eyepiece Hooligan
*****

Reged: 02/28/06

Loc: Petaluma, CA
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: MikeBOKC]
      #5470775 - 10/14/12 11:32 PM

Yep. They are stout little blighters. Like a doublet "blintz".

You can't see it too well from the lens on image, but the cell sits far forward inside the extended dew shade. Only about half the length of the dew shade actually extends past the front element as a result. Dare I say it, but - *sigh* - another questionable design decision on the shade. But for some odd reason these fast 6" achromats have always suffered from "too short dew shade" syndrome. Only the second iteration of the Antares 6" f/6.5 unit fixed the historic dew shade issue.

Here's another "bidness end" shot:



Regards,

Jim


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doctordub
Pooh-Bah


Reged: 01/11/06

Loc: New Rochelle, New York
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: MikeBOKC]
      #5470785 - 10/14/12 11:40 PM Attachment (85 downloads)

Jim, Your star test sounds like you have some SA that I have not seen on mine. I mentioned in another thread you could clearly see the CA as a tight line on the Lunar limb and crater shadows in my photo without chromacor. I find that niether a 6" SCT nor an 8" SCT were a match for my AT 152. I hope the quality controll has not changed since the 1.5 years since I purchased mine.

Luna without chromacor.


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Tank
Carpal Tunnel
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Reged: 07/27/09

Loc: Stoney Creek, Ontario, CANADA
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: doctordub]
      #5471064 - 10/15/12 08:02 AM

Jim,
great review
I have one and looked thru a similar scope
Here are my findings:

Mine Celestron 150mm F5
- On moon CA free up to about 75x
- On moon acceptable to 100x anything over purple creeps in alot
- Planetary high contrast but have to look passed the purple! views are not very pleasing
-Bright stars Vega etc show CA slightly even at 27x at really low power no CA shown 14x
-Very specific scope wide field sweeper low power 100x and under. Best views ive seen of the Veil and double cluster and others.

Looked thru Canadian Telescope 152mm and basically same results! These big achros pretty much act the same.

I tried my scope with a chromacore and the views really cleaned up as far as CA however still thought the views of planets were just ok.


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coopman
Post Laureate
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Reged: 04/23/06

Loc: South Louisiana
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: doctordub]
      #5471071 - 10/15/12 08:07 AM

I have an Antares 127 f/6.5 and it has a good bit of CA as well. Even so, it's still a very entertaining RFT when scanning star fields with a 3 degree FOV. You cannot defeat the laws of physics with a short focus achro unless it has some sort of exotic glass type for its lens.

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Cotts
Just Wondering
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Reged: 10/10/05

Loc: Toronto, Ontario
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: jrbarnett]
      #5471172 - 10/15/12 09:51 AM

Quote:

Dunno, Steve. Perhaps the large swath of defocused portions of the visual spectrum affect the "tightness" of the in-focus stars. Perhaps the optics are a bit rough. Perhaps there's some attenuation happening. Perhaps the baffling isn't as effective as it should be. Lots of possibilities. It's not a bad scope. It's actually a very entertaining scope, but there are several liabilities that come with it that I suspect would irritate many users.

From my perspective there were no surprises. I expected false color, and received it, expected mass and length, and received them, and expected decent optical and mechanical quality, and received them. On the value front, though, unless someone is Hellbent on having a 6" fast achromat, there are other 5 to 8 inchers that would likely be easier to live with and more well-rounded, for the same or less money.

Regards,
Jim




Hi, Jim. I had one of these AT 152' s for about a year. I found the false colour to disappear on stars fainter than mag 3.5. On the overwhelming majority of objects there is zero CA. Zero. Globulars, nebulae, galaxies, planetaries - no false colour. Typical Struve double stars with both components below 4th mag -zero colour and perfect diffraction patterns - and there are a couple of thousand of those to look at...

Not a planetary scope? The views of Jupiter, Mars and Saturn through a #58 Wratten (green) filter were crisp and showed remarkable levels of detail.

I would still be happily using the AT 152 to this day if I had not fortuitously found my current 1988 AP triplet APO at a very good price.

Dave


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dakota
sage
*****

Reged: 12/11/11

Loc: SD (God's Country)
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: t.r.]
      #5471238 - 10/15/12 10:37 AM

Quote:

Jim, don't tell me you didn't look at Jupiter or the moon with this scope?!?




Since I have today (Monday) off, I left the AT152 set up (just covered with a new BBQ grill cover) and got up at 3am CT this morning to view Jupiter and The Pleiades. The Pleiades has a small amount of CA using Siebert 24mm SWA's. Jupiter showed no CA whatsoever with my Pentax 8.5mm XF's.

I must say I am impressed with this scope and the view of Jupiter it presented. I should have pushed the power up higher to see the results, but honestly it was chilly out and our Shih Tzu was talking to me and urging me to come back to bed.


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drollere
Pooh-Bah
*****

Reged: 02/02/10

Loc: sebastopol, california
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: dakota]
      #5471314 - 10/15/12 11:14 AM

interesting review, jim, and certainly deterring. your recommendation to choose a 6" SCT instead invites the conclusion that any achromat below ƒ/6 (or higher?) is a bauble for "the glassaholic who has everything." it also begs the question why one wouldn't use an 8" or 10" ƒ/4 newt for RFT pleasure ... with filter free true color all the way down the eyepiece line.

Quote:

So what do you say to the reviews by Warren Maguire on the CT152 and Larry Carlino on the AT152? Are you saying they are wrong? As usual with your review and the other 2 reviews they are merely self opinions which don't necessarily reflect the views of others.



personally, one of the most fascinating things i've discovered on CN is the fact that optics really are subjective, that an individual's satisfaction with an astronomical image is not something a ray trace or point spread is going to predict or even adequately describe. i thrill when, for example, someone like marcus ludes says something like "overall impression of the chromatical correction is better then I hoped for, from the optical design." the optical design always omits your idiosyncratic eyes.

and then there is the "don't disrespect my lady" response of people who own an instrument that has been negatively reviewed. seems to me like people at some instinctual level understand the subjectivity of the image, and therefore rely on group consensus opinion to anchor the ambiguity, and become upset when consensus or received opinion is challenged.

as you and several posters have stated, even a 6" ƒ/6 achromat is good for *something*, and maybe even very good. and better good, if used in the right way (e.g., with a filter). skill and expectation matter: if you know what to expect, and you expect it won't matter for what you want to do, then the only remaining issue is build quality and price, which you appropriately spell out in component detail.


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dakota
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: drollere]
      #5471364 - 10/15/12 11:39 AM

and then there is the "don't disrespect my lady" response of people who own an instrument that has been negatively reviewed. seems to me like people at some instinctual level understand the subjectivity of the image, and therefore rely on group consensus opinion to anchor the ambiguity, and become upset when consensus or received opinion is challenged.

True! This certainly happens when the views about build quality or anything other than positive mention is made about a Tec or AP or other high price scope.


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coopman
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: drollere]
      #5471365 - 10/15/12 11:39 AM

If you're going to use a f/4 newt., you'd better have a Paracorr available. Coma would be really bad without it.

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idealistic
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Reged: 12/31/10

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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: coopman]
      #5471369 - 10/15/12 11:42 AM

If your particularly sensitive to coma.

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doctordub
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: coopman]
      #5471389 - 10/15/12 11:52 AM Attachment (64 downloads)

I have noted that on the high end scopes more consistency of quality. The descriptions very here because more than likely the scopes very as well. Jim's description of his scope soundl like my Orion 120 ST, that is why I cut 5" off the tube and made it a dedicated binoscope. My AT 152 with Chromacor edges out my IM 703, and clearly beates my 8" Meade SCT.

Edited by doctordub (10/15/12 11:58 AM)


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jrbarnett
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Tank]
      #5471402 - 10/15/12 11:59 AM

Back in the day I purchased one of the "special run" 5" f/10 D&G achromats. In anticipation of the scope, I decided to also buy one of the then-new-fangled "minus violet" filters. Back then there was one little pioneer, now defunct, making them, called Sirius Optics. At that time Sirius had just introduced a second MV filter to address the unnatural star color comments of buyers of the first version. That was what I bought - the "MV-20".

When the D&G arrived, it did indeed have some false color, as you'd expect, but I found that there was not enough false color to make me want to hassle with moving the MV-20 filter around between eyepieces. The MV-20 sat, largely unused (other than one night with my Antares 105/1500, as an experiement at very high magnification), for years.

It was purely as an afterthought that I put it in the eyepiece case when I loaded the AT152 for its first light voyage. On Rasalgethi at 224x the filter did a great job restoring much of the color contrast of the pair and darkening the split. I think that with one of the even more modern MV filters, these scopes are suitable for higher magnification targets if the user is tolerant of the reduced amount of false color that will remain.

I'm not in a hurry to off the scope at this point. As I said earlier, it is pretty much what I expected it wold be. I do plan on following through with my original idea of picking up a new alt-az mount capable of carrying it, and using it as a Peltier-esque "comet seeker".

It also occurs to me that a 40mm 2" 68 degree eyepiece would help counterbalance the front-heavy scope. 6.8mm exit pupil, 3-degree TFOV, 22x, on a solid alt-az mount would make a diabolical giant monocular setup. What an intuitive, easy to use, hands-on hoot for public outreach, with an RDF. Also, what a stunner from a truly dark site where the 6.8mm exit pupil might actually be usable.

These are my first impressions of the scope. I do feel that it is a niche scope. I'm in that niche - always wanted the Peltier experience; drooled over the big Jaegers RFT achros as a cub, etc.). Not every observer will be as enamored with such a scope, though. My comments are intended as "fair warning". That's all.

I'm looking at padded tripod and lighting gear bags for OTA transport.

Regards,

Jim


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jrbarnett
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: drollere]
      #5471445 - 10/15/12 12:23 PM

"it also begs the question why one wouldn't use an 8" or 10" ƒ/4 newt for RFT pleasure"

That's an easy one, Bruce. The eyepiece would be at the wrong end of the OTA.

On a more serious note, I don't feel my review was "negative" but rather "factual". "Negative" is an interpretation of those facts. "A lot of false color on moderately bright targets at modest magnifications" is a fact. I dub chromatism as a "deficiency" not as a personal judgement, but rather based solely on the fact that chromatic aberration is defined as, well, an "aberration". I suppose aberrant behavior isn't always bad, but...

I should also probably dig a little deeper on the C6 versus AT152 front. When I say that I believe most observers would be better served with a C6 (the f/10 SCT, not the C6R achromat) rather than this scope, it has more to do with the three "Cs" (convenience, comfort and cost) than it does with the actual performance of the two scopes at the eyepiece.

In comparing a 6" SCT to the AT152, there is a certain qualitative difference between how an large CO instrument and unobstructed instrument of a given aperture render star images. Using the MV filter in the big achro, there was still plenty of false color at high magnification even on fairly dim stars (Rasalgethi B, for example, is just magnitude 5.4, yet at magnifications north of 200x, shows plentiful false color, even with a MV filter in place), but stars retain that "crispness" systems with large obstructions seem to lack. Stars in the C6 (and other large-obstruction systems) are little quasi-discs rather than points, to my eye. Both systems (SCT and filtered achro) will show the same details (native star color, separation gap), but the way they present has a distinctly different appearance, disregarding the CA. I prefer the refractor's "style" of star rendering, but that is just a personal aesthetic preference.

Even with such a predilection towards refractor weenie-ism, I gotta think most folks would look at the two scopes, think about the relative magnitude of the trials and tribulations involved in living with each, and run screaming from the big achro.

Regards,

Jim


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Patricko
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: jrbarnett]
      #5471490 - 10/15/12 12:43 PM

Quote:

Instead I'd steer you quickly to the $400 Celestron C6 OTA.




After looking through 6" achros at star parties I would have to agree with this, even my ST80 f/5 refractor throws up too much color for me at 22x on mag 2 and brighter stars which is kind of odd because a past ST80 f/5 refractor I had did MUCH better than the current runs of ST80s offered for whatever reason. I really like refractors and am working on finishing off a 60mm f/11.7 project now but I'd have a hard time using a 6" f/5 - f/6.5 achro, my vision is just too good and I notice a LOT of optical defects and spherical aberrations in these scopes, not to mention the color errors. I'm not knocking them and think they are useful but they are not for people with exceptional vision as they will drive you nuts with imperfections without a filter or perfect optical alignment.


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jrbarnett
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: dakota]
      #5471504 - 10/15/12 12:48 PM

A couple of points.

First, I can't recall the last time I saw a quality or performance related criticism of a TEC, Tak or A-P in a forum. Whining about expense, snobbery and the like are plentiful, but complaints about performance are rare. I don't think that the scarcity of bitchin' about quality in these scopes had anything to do with elitism any more than I think every owner of an affordable scope who cannot afford one of these brands has a chip on his shoulder or suffers from "sour grapes" syndrome or has a Napoleon complex.

Sure, there are snobs who buy fancy stuff out of chauvinism, and not for the genuine quality advantages such stuff carries with it. Likewise there are plenty of petty folks who secretly covet what they can't have and adopt a sour-grapes attitude toward it as a result. But neither of those behaviors alter *facts* about the characteristics of different optics.

There are objectively really good quality affordable optics and really poor quality ones. The instances of really poor quality expensive optics, however, are rarer than instances of really poor quality affordable optics. It's not elitist to say it. Rather, I think it's kind of logical to assume that a manufacturer building a scope to a price (say $1000) doesn't have the leeway to put as much work into it as a manufacturer building a scope to a higher price (say $5000).

With respect to this scope, the fact is that it puts up loads of obvious false color, and there is not super-s3cr3t formulation of gnomish fairy-glass that would allow it to behave otherwise for its price. When I read folks claiming not to see it, with all due respect, I think there are three possibilities: (1) they don't know what false color looks like, (2) due to a physiological condition (color blindness, cataracts) the literally can't see it, or (3) they know their lady's butt is big, but for other reasons wholly external to the merits and drawback of a big butt, claim that it it not.

"I like big...er...achros, and I cannot lie." On the other hand, I'm willing to accept that the vast consensus of scope performance characteristic preferences is on the other side of the fence.

Regards,

Jim


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doctordub
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Patricko]
      #5471519 - 10/15/12 12:56 PM

That is why Chromacors still hold their value. I have a baader SA filter that I will not sell because it enhances Jupiter in Achros, Cats, and reflectors. This scope has major CA, but what is surprising to me is how well it is controlled when compared to 6" F8 scopes that I have compared it to. There seems to be many people that have recieved good samples, and some that have had problems when looking at different responces on CN, AM, and other sites. What fascinates me is how when significant numbers of experienced observers have different results it must be the observers. I give weight to observers that have actually used the equipment they are talking about.
CS
Jonathan


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doctordub
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Reged: 01/11/06

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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: doctordub]
      #5471529 - 10/15/12 01:02 PM

Jim,
This bag is $199.00 but a few people with the AT 152 have used it.
http://www.opticsplanet.com/stellarvue-deluxe-heavy-duty-thickly-padded-telescope-case.html

CS
Jonathan


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Tank
Carpal Tunnel
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Reged: 07/27/09

Loc: Stoney Creek, Ontario, CANADA
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: jrbarnett]
      #5471597 - 10/15/12 01:40 PM

Jim
I like to display the facts out on the table too for people looking into buying one of these larger short tube Achro.
CA you will see and a MV or a CC will help reduce CA but REDUCE is the KEY word!
Ive compared with a MAK and a Triplet APO spliting stars at around 150-200x and well the Archo does poor!
When compared side by side the Achro shows more CA than you think than if you were just viewing with the Achro without anything to compare to.
However there is a great side to these is the resolving power for WF views! Resolving M11 at 15x-30x is wonderful
Pleades is awesome and other views are just stunning!
Too me its the best scope for paning around the sky at low mag.
There really isnt one scope that can do it all!


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jrbarnett
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: doctordub]
      #5471634 - 10/15/12 01:57 PM

Thanks Jonathan.

Looks interesting.

Regards,

Jim


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dakota
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Reged: 12/11/11

Loc: SD (God's Country)
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: jrbarnett]
      #5471834 - 10/15/12 04:22 PM

Quote:



I don't think that the scarcity of bitchin' about quality in these scopes had anything to do with elitism any more than I think every owner of an affordable scope who cannot afford one of these brands has a chip on his shoulder or suffers from "sour grapes" syndrome or has a Napoleon complex.

folks who secretly covet what they can't have and adopt a sour-grapes attitude toward it as a result.






To me it's not a question of money. I could buy a much higher price scope. But I won't. I would find it hard to spend 4 to 8 thousand dollars on a scope that would show no CA and be perfect so to speak. The views I want I get from the scopes I have. I have nothing against those that do spend big bucks on scopes. To each his own. It's their money and they can do with it what they want. It's like that with other things besides telescopes.

I'm in this hobby for the enjoyment of looking into the heavens. I'm not one to pick fly$hit out of pepper for that last photon. As long as you are happy, great. As long as I'm happy, that's even better.


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jrbarnett
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Tank]
      #5471881 - 10/15/12 04:57 PM

I agree.

The combination of loads of context (i.e., lots of surrounding sky) and partial resolution of a bright globular courtesy at low magnification of the extra aperture, is really nice. Unless you happen to have a second magnitude or brighter star in the FOV, you likely won't notice the false color at low magnifications on DSOs.

That's the magic of a 6-inch scope with a 3-degree TFOV. I suspect folks with NP-127s experience a similar effect on such targets.

Regards,

Jim


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Bill Barlow
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: doctordub]
      #5472025 - 10/15/12 06:11 PM

Quote:

Jim, Your star test sounds like you have some SA that I have not seen on mine. I mentioned in another thread you could clearly see the CA as a tight line on the Lunar limb and crater shadows in my photo without chromacor. I find that niether a 6" SCT nor an 8" SCT were a match for my AT 152. I hope the quality controll has not changed since the 1.5 years since I purchased mine.

Luna without chromacor.




Were you just comparing views of planets and the moon with your AT 152 against 6" and 8" SCT's? Or was that for several deep sky targets as well.

Bill


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Tank
Carpal Tunnel
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: jrbarnett]
      #5472056 - 10/15/12 06:27 PM

Jim
Yup thats the magic of the 6" short tube the larger apeture resolving power in combination of the WF views.
Ive looked thru a 120 Achro and a 111 APO and they had no where near the resolving power punch of the 6" Achro.
The way to get rid of the CA on brighter star with higher mag. is to use a CC but they tend to $$$ so i usually sweep at around 27x 3 degree FOV in the 28mm WO UWAN which is really corrected at F5.


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doctordub
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Loc: New Rochelle, New York
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Bill Barlow]
      #5472109 - 10/15/12 06:55 PM

When observing open clusters, globular clusters, and planets the AT 152 with Chromacor, Baader SA filter or no filter is a clear choice.
CS
Jonathan


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stevew
Now I've done it


Reged: 03/03/06

Loc: British Columbia Canada
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: jrbarnett]
      #5472542 - 10/15/12 11:54 PM

Quote:

When I read folks claiming not to see it, with all due respect, I think there are three possibilities: (1) they don't know what false color looks like, (2) due to a physiological condition (color blindness, cataracts) the literally can't see it, or (3) they know their lady's butt is big, but for other reasons wholly external to the merits and drawback of a big butt, claim that it it not.

"I like big...er...achros, and I cannot lie."
Regards,

Jim



Jim, you certainly have a way with words.


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drollere
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: coopman]
      #5472659 - 10/16/12 01:40 AM

Quote:

If you're going to use a f/4 newt., you'd better have a Paracorr available. Coma would be really bad without it.




actually ... for what it's worth ... my cheapo AT 10" yields extremely nice views with a 22mm LVW (1.25" barrel). that's a 5.5 exit pupil, just about right for me (my pupil stops at 5.9mm). i've tried it with a coma corrector and didn't see much difference.

like i said ... diff'rent strokes. all types make the world go 'round. et cetera.


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drollere
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: jrbarnett]
      #5472666 - 10/16/12 01:51 AM

Quote:

"it also begs the question why one wouldn't use an 8" or 10" ƒ/4 newt for RFT pleasure"
...
That's an easy one, Bruce. The eyepiece would be at the wrong end of the OTA.




jim, you need a shorter mount ... or taller shoes.


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doctordub
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Bill Barlow]
      #5473129 - 10/16/12 11:30 AM

Quote:

Quote:

Jim, Your star test sounds like you have some SA that I have not seen on mine. I mentioned in another thread you could clearly see the CA as a tight line on the Lunar limb and crater shadows in my photo without chromacor. I find that niether a 6" SCT nor an 8" SCT were a match for my AT 152. I hope the quality controll has not changed since the 1.5 years since I purchased mine.

Luna without chromacor.




Were you just comparing views of planets and the moon with your AT 152 against 6" and 8" SCT's? Or was that for several deep sky targets as well.

Bill




Bill, the 8" SCT is a little brighter on DSO, but the view in the AT 152 was more pleasing. This is after the Cat is properly cooled. My scope has almost no SA which is why I waited for a Null corrected Chromacor, but the with the CC in place it snaps to focus.

CS
Jonathan


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Mary
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Loc: Highlands Ranch, CO
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: stevew]
      #5473372 - 10/16/12 02:14 PM

Quote:

Quote:

(3) they know their lady's butt is big, but for other reasons wholly external to the merits and drawback of a big butt, claim that it it not.





Oh my goodness!!!!!

Mary


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Eric Gage
Pooh-Bah
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: dakota]
      #5473494 - 10/16/12 03:54 PM

Quote:

So what do you say to the reviews by Warren Maguire on the CT152 and Larry Carlino on the AT152? Are you saying they are wrong? As usual with your review and the other 2 reviews they are merely self opinions which don't necessarily reflect the views of others.




What is any review but someone's opinion?


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Eric Gage
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: drollere]
      #5473498 - 10/16/12 04:00 PM

Quote:

interesting review, jim, and certainly deterring. your recommendation to choose a 6" SCT instead invites the conclusion that any achromat below ƒ/6 (or higher?) is a bauble for "the glassaholic who has everything."





Jim works hard to fit that description.


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jrbarnett
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Eric Gage]
      #5473515 - 10/16/12 04:06 PM

Aww c'mon fellas! I been selling stuff! ~$5k worth of eyepieces thus far, and I'll get ready to do another tranche of 'em this weekend.

Just you wait 'til I get to the OTAs. You'll see.

My goal is to pick up Hubble cheap, given it's mounting maintenance costs and planned deactivation, and then use my X Prize competition entry to get up there and do a little cleaning and collimating and such.

- Jim


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Eric Gage
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: stevew]
      #5473680 - 10/16/12 05:38 PM

What do you think of that focuser, Jim?

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dakota
sage
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Reged: 12/11/11

Loc: SD (God's Country)
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Eric Gage]
      #5473719 - 10/16/12 06:01 PM


What is any review but someone's opinion?




No $hit! Well I guess us folks in South Dakota didn't know that.



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johnnyha
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: dakota]
      #5473855 - 10/16/12 07:19 PM

The funniest part is when you actually read Larry's review you can see he essentally agrees with Jim, saying things like "Jupiter, always a demanding target for any telescope, showed a bath of purple surrounding its disc" etc.

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jrbarnett
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Eric Gage]
      #5473865 - 10/16/12 07:22 PM

It's not a bad unit, Eric, but there is a little rocking/twisting on my unit during focus adjustment, which might not be so great for an imager. For visual, though, it works pretty well, even with decent sized eyepieces. The Long Pern on the AT scopes and others is a little bit smoother, but the SV might have a slight edge in load capacity. Pretty much a toss-up between the two.

I think the focuser is a good match for the scope and in fact has fit and finish a cut above the rest of the OTA. On the other hand, I think the $300+ Stellarvue is asking for these focusers standalone is ridiculous. For that money, a Moonlite or Feathertouch are a much better choice, but bundled in with a scope, it's a fine visual use focuser. I'm happy with it.

Regards,

Jim


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jrbarnett
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: dakota]
      #5473873 - 10/16/12 07:23 PM

"Well I guess us folks in South Dakota didn't know that."

That explains a lot. I'll be giving charitable donations to SD public schools next year. Anything to help. Thanks!

- Jim


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jrbarnett
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: drollere]
      #5473877 - 10/16/12 07:25 PM

You've met me, Bruce. You *know* I could use taller shoes.



- Jim


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Gord
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: dakota]
      #5474058 - 10/16/12 09:17 PM

Quote:

The Pleiades has a small amount of CA using Siebert 24mm SWA's. Jupiter showed no CA whatsoever with my Pentax 8.5mm XF's.





This sounds like exactly the thing that Jim was commenting on earlier about people's comments about CA in scopes, especially ones that are for sure going to have boatloads of it. You may feel that there was no CA present, but there certainly was.

However, there do seem to be differences between people's sensitivity to it, and tolerance especially on a relative scale. If you don't have a perfect apochromatic view to compare against, a huge amount of CA next to a lot of CA may not seem all that bad. The effect is most noticeable when side-by-side.

I notice CA quite easily. My 6" F10 shows lots, especially on Jupiter. Still delivers a nice image with lots of details. And the more you look, the less you notice the purple haze. Alas, it's always there, and always degrading the image.

I remember one week a couple of years ago when a nice omega block moved in over the NE region. PERFECT skies for almost an entire week! The 6" achro was showing a beautiful image of Jupiter. One night, I decided to drag the 10" out as well since the views were so nice. That's when I realized how much was actually missing in the view from the 6". The CA was horrendous by comparison and there was so much more fine detail in the 10".

I guess that's the point of comparisons. Any well produced scope should perform great relative to what IT is supposed to do. But that doesn't tell you much until you look at it in context relative to what others do. I'm sure these fast achros do very nicely for what they were intended to do. They can do other things too, but planetary scopes they are not.

Clear skies,


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Gord
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Gord]
      #5474066 - 10/16/12 09:23 PM

Jim,

That's an interesting observation relative to the C6. I expect that your C6 is one of the more recent ones with Starbright XLT coatings?

Celestron's SCT's with that seem to be extremely bright I find. This is based on my own 3 samples with this. I expect the very good performance of these coupled with a slight loss of contrast due to CA at the very limit of detectability is what makes the little SCT edge out the fast achro.

I suppose there could be some kind of internal vignetting going on as well that you could check.

Clear skies,


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stevew
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Reged: 03/03/06

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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: jrbarnett]
      #5474077 - 10/16/12 09:29 PM

Quote:


My goal is to pick up Hubble cheap, given it's mounting maintenance costs and planned deactivation, and then use my X Prize competition entry to get up there and do a little cleaning and collimating and such.

- Jim



We will all be looking forward to your review.
Make sure your review includes a test without the COSTAR

Steve


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stevew
Now I've done it


Reged: 03/03/06

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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: doctordub]
      #5474079 - 10/16/12 09:30 PM

Johnathan, thats a great Moon shot, even with out the Chromacor.

Steve


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stevew
Now I've done it


Reged: 03/03/06

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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: jrbarnett]
      #5474090 - 10/16/12 09:39 PM

A review by Terence Dickinson of the Canadian Telescope labeled version can be read here.
www.skynews.ca/PDFs/BigGlass_6inch-refractor.pdf


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John Miele
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: jrbarnett]
      #5474182 - 10/16/12 11:11 PM

Quote:

...I felt that the Double Cluster wasn't showing as many stars as it should (i.e., looked surprisingly under-resolved for the aperture.






Jim, could you please explain in a little more detail just why you said this? Did you compare the view to another 6" scope and see more stars? Was there a certain magnitude you were trying to drill down to but could not see? I only ask because I also own the AT152 and just got done with three nights of viewing a variety of targets including the double cluster and this is the LAST thing I would have said. I felt like the tiny faint stars just went on forever in this cluster with a 17mm Nagler. I am very surprised at your statement. Please elaborate on how you drew that conclusion...thanks...John

Edited by John Miele (10/16/12 11:17 PM)


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jrbarnett
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: John Miele]
      #5474210 - 10/16/12 11:31 PM

Howdy John.

First off, I was observing from suburban Sonoma county; a little farm owned by CNer cuzimthedad. NELM at zenith during the earlier parts of the session was ~5, with a fair amount of glow nearer the horizons. Transparency was average at the beginning of the session and got worse toward the end of the session.

It's possible that the cluster was nested in slightly lower contrast eastern horizon skies when I observed it in the AT152 and was higher and in less washed out skies when I observed it from home after unloading the car and setting up the C6. But countering that theory are the facts that my home site is a half magnitude brighter on average than the farm, and transparency was a lot worse after I got home.

But be that as it may, when I observed the cluster in the AT152 using a 27mm Panoptic (33x; 2 degree TFOV) and a 14mm Meade S2K UWA (64x; 1.3 degree TFOV), the star count seemed pretty low. That is, I'm used to saturation for the two clusters in 6" and above and the view through the AT152 looked more akin to what a 4-incher shows under suburban skies with dark lanes and gaps between stars.

The C6 from home showed the old Double Cluster that I know and love; which in a 6-incher hints at myriad stars within those gaps and channels between the brighter members.

Regards,

Jim


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dakota
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: jrbarnett]
      #5474531 - 10/17/12 06:40 AM

Quote:

"Well I guess us folks in South Dakota didn't know that."

That explains a lot. I'll be giving charitable donations to SD public schools next year. Anything to help. Thanks!

- Jim




Don't look now but your immaturity is showing.


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johnnyha
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: dakota]
      #5474564 - 10/17/12 07:22 AM



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t.r.
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: johnnyha]
      #5474643 - 10/17/12 08:39 AM

Quote:

This sounds like exactly the thing that Jim was commenting on earlier about people's comments about CA in scopes, especially ones that are for sure going to have boatloads of it. You may feel that there was no CA present, but there certainly was.



I think this is the reason Jim bought the scope and posted a review here. Many people were touting this scope as a planetary/lunar performer with little to no CA. The design facts didn't fit the claims and if Jim didn't buy one I was going to (they were sold out at the time). I thank Jim for purchasing the scope and taking the time to give his impressions providing another data point that people can use. I'm also happy that he saved me some money that I can spend on other gear! Hey, we all want a scope that is Da Bomb for the Buck...although a nice scope and quite capable, this one isn't all that! And this review or comments shouldn't be taken personally...which happens all too frequently here. The hardest thing for a reviewer to do is to seperate themselves from emotion and remain objective.


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johnnyha
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: t.r.]
      #5474660 - 10/17/12 08:57 AM

Personally, I have never looked through a 6" f6 Chinese achro but I have looked through many 6" f8 achros and the chromatic aberration for me is intolerable - I'd much rather have a decent 6"" f8 dob. But then I'm a planetary/lunar guy, I'm sure the f6 achro is fine for deep sky as Jim and all the other reviewers have said.

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t.r.
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: johnnyha]
      #5474708 - 10/17/12 09:27 AM

This scope may be Da Real Bomb...

http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Board/vendorann/Number/5463445/page/0/view/collapsed/sb/5/o/all/fpart/1


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doctordub
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Reged: 01/11/06

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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: t.r.]
      #5474731 - 10/17/12 09:42 AM

I have noted that the double cluster while slightly brighter in the 8" sct than my IM703 and AT152, more stars were resolved in the IM703, I need to do a side by side tonight with the AT152 and the 8" Meade sct.
CS
Jonathan


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Mark Costello
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: jrbarnett]
      #5474763 - 10/17/12 09:57 AM

Quote:

Howdy John.

First off, I was observing from suburban Sonoma county; a little farm owned by CNer cuzimthedad. NELM at zenith during the earlier parts of the session was ~5, with a fair amount of glow nearer the horizons. Transparency was average at the beginning of the session and got worse toward the end of the session.

It's possible that the cluster was nested in slightly lower contrast eastern horizon skies when I observed it in the AT152 and was higher and in less washed out skies when I observed it from home after unloading the car and setting up the C6. But countering that theory are the facts that my home site is a half magnitude brighter on average than the farm, and transparency was a lot worse after I got home.

But be that as it may, when I observed the cluster in the AT152 using a 27mm Panoptic (33x; 2 degree TFOV) and a 14mm Meade S2K UWA (64x; 1.3 degree TFOV), the star count seemed pretty low. That is, I'm used to saturation for the two clusters in 6" and above and the view through the AT152 looked more akin to what a 4-incher shows under suburban skies with dark lanes and gaps between stars.

The C6 from home showed the old Double Cluster that I know and love; which in a 6-incher hints at myriad stars within those gaps and channels between the brighter members.

Regards,

Jim





FWIW, I've counted about 100 stars in the Pleiades several times using a 4"F6.5 achromat (95-110 on individual counts). According to a 80s vintage edition of Telescope Handbook and Star Atlas, one should be able to see 105 stars (presumably with something like a 6" Newtonian)....

M45 is on its way to prime time location for evening observation. When it gets there, I'll have to do this with my 5" F6.5 achro....


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maknewtnut
Member
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Reged: 10/08/06

Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: dakota]
      #5474809 - 10/17/12 10:24 AM

Quote:

Jupiter showed no CA whatsoever with my Pentax 8.5mm XF's.





Opinions can tend to defy the laws of physics.


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dakota
sage
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Loc: SD (God's Country)
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: maknewtnut]
      #5474858 - 10/17/12 11:07 AM

Quote:

Quote:

Jupiter showed no CA whatsoever with my Pentax 8.5mm XF's.





Opinions can tend to defy the laws of physics.




Whatever you say lol


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jrbarnett
Eyepiece Hooligan
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Loc: Petaluma, CA
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: dakota]
      #5474891 - 10/17/12 11:30 AM

Correction: my "precious, erudite immaturity," if you please. I am only 11 years old, after all. That's how we grow 'em out left...er...west, pahtnah.

- Jim


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doctordub
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: dakota]
      #5474896 - 10/17/12 11:32 AM

You have seen the well defined CA on my Lunar images, but yet I have seen haze and thin clouds compleatly remove CA from the Moons Limb!
PS
Laws can be bent just like light.
CS
Jonathan


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dakota
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: doctordub]
      #5474907 - 10/17/12 11:42 AM

To be honest I've seen your pictures and perhaps the monitors I'm viewing them on are not up to par. I have not had a chance to view the moon thru this scope but plan on doing so at the earliest opportunity.

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Eric Gage
Pooh-Bah
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Reged: 12/13/05

Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: jrbarnett]
      #5475035 - 10/17/12 12:53 PM

Quote:

It's not a bad unit, Eric, but there is a little rocking/twisting on my unit during focus adjustment, which might not be so great for an imager. For visual, though, it works pretty well, even with decent sized eyepieces. The Long Pern on the AT scopes and others is a little bit smoother, but the SV might have a slight edge in load capacity. Pretty much a toss-up between the two.

I think the focuser is a good match for the scope and in fact has fit and finish a cut above the rest of the OTA. On the other hand, I think the $300+ Stellarvue is asking for these focusers standalone is ridiculous. For that money, a Moonlite or Feathertouch are a much better choice, but bundled in with a scope, it's a fine visual use focuser. I'm happy with it.

Regards,

Jim




Thanks. I'm glad I went the route I did (although Jonathan has me Jonesing for the SV scope bag now), but it's nice to know that there is a lower cost R & P alternative on the market.


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bobhen
professor emeritus


Reged: 06/25/05

Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: doctordub]
      #5475057 - 10/17/12 01:06 PM

Quote:

You have seen the well defined CA on my Lunar images, but yet I have seen haze and thin clouds compleatly remove CA from the Moons Limb!
PS
Laws can be bent just like light.
CS
Jonathan




Clouds, filters, or one’s imagination, CANNOT remove CA from a standard 150mm F6 lens. Only adding exotic glass or additional lens elements to the lens farther down the tube can remove CA.

Bob


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t.r.
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: bobhen]
      #5475214 - 10/17/12 02:28 PM

A filter most certainly removes CA! Look through a red,blue or green filter and all the detail available in that respective channel will be there just like it is in an apo. Bringing them together to common focus is the real trick of apo refractors or mirrored scopes. In the "Introduction to Observing and Photographing the Solar System", Dobbins,Parker and Capen state that Achro users should be employing colored filters to cancel the CA. Used as such achros are indeed fine planetary scopes while still having an edge on low contrast planetary detail. In addition, binoviewing is purported to reduce the amount of CA seen in achros, perhaps due to the reduction in brightness...kinda like a cloud does!

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nirvanix
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: t.r.]
      #5475236 - 10/17/12 02:44 PM

I've read from reputable sources that some people's optical/brain system removes the violet as it processes the image. I seem to have that ability as I hardly notice it at all, but when I want to notice it, I can by simply concentrating on looking for it.

PS about the Canadian Telescopes version of this scope:
"I was surprised by the sharpness of the optics. In fact, this is the best f/6-class achromatic refractor I have ever looked through." - Terence Dickinson (Editor in Chief) in SkyNews Magazine


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DarkStar1984
member


Reged: 07/10/12

Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: dakota]
      #5475250 - 10/17/12 02:54 PM

I have been following this thread because I was interested in buying a large aperture refractor. I was wondering if any one has heard anything or has any experience using a TS Individual Rich Field Refractor 152/900mm f/5.9? Thanks!

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t.r.
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: nirvanix]
      #5475255 - 10/17/12 02:59 PM

Well, he is Canadian, isn't he? I bet he only drinks Molson's Golden too!

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Tank
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: nirvanix]
      #5475266 - 10/17/12 03:05 PM

Put the big Achro up against a pure CA free image and then you will see the diffence!
I have run across a few people recently at a star party looking thru a big Archo
152 F5.9 on the moon about 150x
The topic of CA came up and here how it played out:
I was fourth in line to view thru this scope
-Owner said there is no CA at all that he can detect thru the scope.
-His buddy agreed with them and said there was no CA
-Third was a newbie and said he agrees
-I came to the scope and saw loads of CA, moon was cover in a purple haze.

Three against one i guess i was wrong
The problem is i dont think any one of them ever looked thru another scope and or a few didnt know and the owner was in denial.
Moral of the story you can run into 10 people and 9 might not know what there talking about so the incorrect answer is correct

Anyhow these moster Short tube achros are made for a WF sweeper/panner yes they can be used for planetary but i would rather looked thru a CA free 80-100mm, views are more pleasing.


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Tank
Carpal Tunnel
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: DarkStar1984]
      #5475275 - 10/17/12 03:09 PM

Quote:

I have been following this thread because I was interested in buying a large aperture refractor. I was wondering if any one has heard anything or has any experience using a TS Individual Rich Field Refractor 152/900mm f/5.9? Thanks!




Should be about the same as the other scopes we are talking about here.
It a depends on what your expectations are for this scope!


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Gord
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Tank]
      #5475337 - 10/17/12 03:50 PM

Here's an interesting note on these fast achro's:

IStar makes quite a few varieties of achro's, including some fast ones up to pretty big sizes (there's a few 8" F6's out now...). The design parameters for these fast scopes are for a max magnification of 0.25D in mm.

For a 6" like this one, that's 38x. Yes they can be used at higher powers than that of course, but it's outside the design spec and quality of the image isn't guaranteed to be good.

From everything I have seen with fast achros (I had an 80mmF5 for a long time) and heard, they do very nicely in that 0.25D range. But by the time you hit even 1D on them, things aren't looking so hot (pretty terrible actually...).

If you look at any of those numbers (150x in this case if pushed to 1D), they are just barely entering planetary performance arena in terms of what is needed for details. But certainly a fun specialized second (or third, or fourth, or ...) scope!

Clear skies,


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johnnyha
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: dakota]
      #5475456 - 10/17/12 04:55 PM

Quote:

Quote:

Quote:

Jupiter showed no CA whatsoever with my Pentax 8.5mm XF's.





Opinions can tend to defy the laws of physics.




Whatever you say lol




Excuse me, aren't you the same guy who accused 11 year old Jim of immaturity?


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Mark Costello
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Tank]
      #5475513 - 10/17/12 05:27 PM

Quote:

Put the big Achro up against a pure CA free image and then you will see the diffence!
I have run across a few people recently at a star party looking thru a big Archo
152 F5.9 on the moon about 150x
The topic of CA came up and here how it played out:
I was fourth in line to view thru this scope
-Owner said there is no CA at all that he can detect thru the scope.
-His buddy agreed with them and said there was no CA
-Third was a newbie and said he agrees
-I came to the scope and saw loads of CA, moon was cover in a purple haze.

Three against one i guess i was wrong
The problem is i dont think any one of them ever looked thru another scope and or a few didnt know and the owner was in denial.
Moral of the story you can run into 10 people and 9 might not know what there talking about so the incorrect answer is correct

Anyhow these moster Short tube achros are made for a WF sweeper/panner yes they can be used for planetary but i would rather looked thru a CA free 80-100mm, views are more pleasing.




Based on my experience with a 4"F6.5 achro and now a 5"F6.5 achro, the moon is not that tough a test for an achromatic refractor. I've spent hours viewing and drawing lunar features and I never have seen evidence of chromatic aberration by looking DIRECTLY at the lunar surface features. I see it when I look at the lunar rim.

My experience is that the planets make for sterner tests for achromats. The false color is easier to spot on Jupiter and Saturn when I have magnification turned up to about 200X (236X with my 5", a 7mm TMB, and a 2X TV Barlows). That's because I can still see the entire disc in a jet deep purple background. But if I look at the moon at that power, I'm just looking at a small portion of the disc and so unless it includes the rim I just don't see the purple there. So frankly, I'm not surprised by the reactions evidenced in the note here.

When it's at its closest, Mars is tougher or at least seems that way than Jupiter and Saturn. A while back I estimated that its intensity would be a little higher (light output per cross section area) which might be a reason for this. I don't do Venus and won't until I get one of those inexpensive apos, you know, the ones that work with mirrors.


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jrbarnett
Eyepiece Hooligan
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Reged: 02/28/06

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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: johnnyha]
      #5475514 - 10/17/12 05:27 PM

Ahem, "Little Jimmy" please.

- Jim


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Agatha
Pooh-Bah


Reged: 06/04/12

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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: johnnyha]
      #5475518 - 10/17/12 05:33 PM

I must be missing something.

Linda B.


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johnnyha
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Agatha]
      #5475541 - 10/17/12 05:42 PM

Quote:

I must be missing something.

Linda B.




Yes, page 4 near the bottom. Jim, er, Little Jimmy is only 11 years old. Which makes his "Eyepiece Resolution World Cup" from 2009 even more impressive.


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bobhen
professor emeritus


Reged: 06/25/05

Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: t.r.]
      #5475543 - 10/17/12 05:43 PM

Quote:

A filter most certainly removes CA! Look through a red,blue or green filter and all the detail available in those channels will be there. Bringing them together to common focus is the real trick. In the "Introduction to Observing and Photographing the Solar System", Dobbins,Parker and Capen state that Achro users should be employing colored filters to cancel the CA. Used as such achros are indeed fine planetary scopes while still having an edge on low contrast planetary detail. In addition, binoviewing is purported to reduce the amount of CA seen in achros, perhaps due to the reduction in brightness...kinda like a cloud does!




Filters just block the unfocused CA light from reaching your eye. They DO NOT correct CA. The problem with CA is that part of the information in the spectrum is never delivered to the viewer because it is out of focus – filters do not bring the lost light back into focus. Only additional lenses or exotic glass can do that.

Here are 2 comments by Roland Christen…

“Chromatic aberration in a doublet achromat does not vary with design, glass type, aperture, focal length, uneven lens spacing, SA, turned edge, pinching, zones, etc. Chromatic aberration is essentially constant because the non-linear characteristics of crown and flint are fixed values. They do vary from one glass to another, but only by very tiny amounts. A typical achromat will have 1 part in 1750 C-F at worst to perhaps 1 part in 2000 C-F at best. That would include thousands of glasses that are available to make an achromat”.

“One saving grace for achromats is a set of filters. It does not "fix" the chromatic aberration, rather it lets you see the image in one color in monchrome very sharply.”

Bob


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jrbarnett
Eyepiece Hooligan
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Reged: 02/28/06

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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: bobhen]
      #5475620 - 10/17/12 06:13 PM

Good post, though I'm not sure what Roland means by "monochrome" views with filters. A modern minus violet filter seems to work a lot like a modern broadband filter in that it suppresses only certain unwanted visual wavelengths, passing the rest. The resulting view is polychrome, not monochrome, though it lacks certain filtered bandwidths.

In turn I really wish the purveyors of achromats would include with their products a color crossing graph and MV filter makers would provide passband data like narrow and boradband filter makers do. To the extent that achromats (particularly those using glasses other than standard crowns), can "skew" the color error in different directions along the spectrum. That being the case, it seems to me that with those data sets one could select a minus violet filter that suppresses the specific color error peak for your particular achromat.

The Sirius MV-20 I used on the scope I tested made a world of difference cleaning up high power images of double stars. The MV-20 was an alternate design to the original MV-1. I assume other minus violet filters differ maker to maker and model to model too.

- Jim


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jrbarnett
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: jrbarnett]
      #5475637 - 10/17/12 06:20 PM

It looks like lighting umbrella and tripod bags, with padding, are a lot cheaper for these than the SV case linked earlier ($199 for the SV case versus $25-$45 for a similarly sized padded lighting/tripod bag). FYI.

Regards,

Jim


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t.r.
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: jrbarnett]
      #5475744 - 10/17/12 07:42 PM

Really Bob, you didn't understand my post?!?! You view in a single monochrome color...RED, Blue, green or whatever. That single color will block ALL other colors of the rainbow to include that defocused red/blue combo called CA! Bam, CA gone!!! I never said it refocused or corrected CA. When I wrote "Bringing them together to common focus" I was talking about what triplet apo's do or of course a mirror! WOW, I know I don't articulate well, but come on... I've gone back an edited it for clarity.

Jim, Roland means this very thing...viewing through ONE color filter at a time, not a minus violet, planetary observers of old would simply cycle through the colors sketching various details that each individual color would show. Certain colors were prefered for certain planets, light yellow for Saturn, light red for Mars, light green for Jupiter if it was the only filter to be used. Now, the minus violet filter has changed the game allowing more wavelengths to pass through attempting to deliver a more naturally "colored" image.


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Eric Gage
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: jrbarnett]
      #5475752 - 10/17/12 07:46 PM

I'll have to take a run over to National Camera, but I haven't seen anything particularly comparable on their website.

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Mike4242
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: drollere]
      #5475801 - 10/17/12 08:19 PM

https://www.youtube.com/watch?v=5DmYLrxR0Y8

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Cotts
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: bobhen]
      #5475868 - 10/17/12 09:03 PM

I have no problem reporting the excessive, debilitating CA of the AT 152 f/5.9 and have done so. On Jupiter, Venus, Saturn, Mars, the Moon and stars like Vega, Sirius, and on down to 3rd magnitude or so. I have said this repeatedly when describing the performance of this scope based on my 18 months' ownership of one. I have also repeatedly reported another aspect of the performance of the scope but it seems to be ignored or even discounted by some here.

The CA visible is proportional to the magnitude of the object being viewed. At a certain magnitude the CA disappears. This threshold differs for each person - for me the borderline was magnitude 3.5. Stars fainter than this, no matter how much magnification was put in place, (and, as a dedicated double star observer, I'm no stranger to pouring on the x's...) showed only a perfect diffraction pattern. For some others here that threshold might be mag 4.5. No matter. The CA becomes invisible at some point. . I doubt anyone here could see any CA on any of the stars in M11 at 250x - in fact I will flat out declare that no one can.

Many here say the AT 152 is great for deep sky sweeping at 28x and they are right. But it is equally great for deep sky sweeping at 200x or whatever. I found and observed nearly half of the Herschel 400 with this scope with no trace of CA to hamper the observation.

Any achromat is essentially APOchromatic below a certain magnitude threshold which is dependent on f/ratio, aperture and the vagaries of the human eye. The out of focus red + blue light disappears and you're left with the in-focus green/yellow light that the lens is corrected for.

I will grant another knock against the achromat - limiting magnitude. I have no doubt at all that the limiting magnitude of the AT 152 is not as good as an equal aperture APO. A star only puts out so much light and if you're 'tossing out' the red and blue because it is not at the same focus as the green/yellow then you won't see as faint objects in the Achro.

And, yes, I do know what CA 'looks like', having owned achromatic CA monsters like the AT 152, Celestron 6" f/8 and the APM 8" f/9 in the past. Each of these scopes were CA free below a certain magnitude. IIRC the Celestron lost the CA around mag 3 and the APM showed it down to mag 5.5 or so.

I highly recommend the AT 152 for deep sky at any magnification you care to use and for double star work - especially going deep into the Struve list at 6 -11 magnitude. On the other hand, planetary performance is not good at all due to the CA reducing contrast drastically, the very faintest threshold galaxies and other faint fuzzies may be missed and you'd have to be out of your mind to try long exposure astrophotography with one...

Dave


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Jan Owen
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Cotts]
      #5476013 - 10/17/12 10:36 PM

Thanks, Dave!

How sharp are field stars in the f/5.9 achro, extreme edge to extreme edge with low power (such as 16, 20, 24, 26, 31 mm), Nagler type eyepieces on objects like the Double Cluster? I particularly like clusters like the DC, when ALL the stars are in sharp focus...

This scope is sounding better and better all the time.

Edited by Jan Owen (10/17/12 10:40 PM)


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jrbarnett
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Jan Owen]
      #5476030 - 10/17/12 10:45 PM

Jan:

Moving back and forth between an Astro-Tech Titan II ED 30mm and Panoptic 27mm, the Panoptic was much, much better corrected at the edges than the Titan. From this I'd extrapolate that the scope benefits from eyepieces corrected for astigmatism in fast scopes. There is also a bit more field curvature visually than I'm used to in refractors but other than finder scopes this is the fastest refractor I own. It's not as bad as the FC in the typical f/10 standard SCT, though, so not a biggie.

Regards,

Jim


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maknewtnut
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Jan Owen]
      #5476095 - 10/17/12 11:31 PM

Jan,
Petzval refractors and Mak-Newts might be the prescription you're looking for. Both have the common trait of providing wide, flat fields. A Schmidt-Newt might fit the bill very well too.


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Cotts
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Jan Owen]
      #5476507 - 10/18/12 08:08 AM

Quote:

Thanks, Dave!

How sharp are field stars in the f/5.9 achro, extreme edge to extreme edge with low power (such as 16, 20, 24, 26, 31 mm), Nagler type eyepieces on objects like the Double Cluster? I particularly like clusters like the DC, when ALL the stars are in sharp focus...

This scope is sounding better and better all the time.




The field was slightly soft on the outer edge with 31 Nagler. With the 17 Ethos I'd have to really concentrate on the edge to see a problem.

I imagine you might find eyepieces whose focal plane curvature matches the curved focal plane of the telescope but it would involve some experimentation and the borrowing of a lot of eyepieces.

Dave


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t.r.
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Cotts]
      #5476568 - 10/18/12 09:10 AM

Quote:

I highly recommend the AT 152 for deep sky at any magnification you care to use and for double star work - especially going deep into the Struve list at 6 -11 magnitude. On the other hand, planetary performance is not good at all due to the CA reducing contrast drastically




I just read through Terence Dickinson's review of the CT version of this scope. He states that it showed slightly more detail than a 5" apochromat on Saturn! He also states that at 180x, Saturn was sharp and contrasty and that the fringing was barely noticable. If so, I would have to say that this is indeed a planetary scope if it can keep with or surpass, as Dickinson claims, a 5" apo... However,I gotta go with Dave on this one. I will say that Barry at D & G told me that a 1" larger achromat will match a 1" smaller apochromat on planetary detail. I guess I would have to see for myself...


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chboss
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: t.r.]
      #5476710 - 10/18/12 10:54 AM

Quote:

I will say that Barry at D & G told me that a 1" larger achromat will match a 1" smaller apochromat on planetary detail. I guess I would have to see for myself...




D&G makes long focal length achromats that is a whole different story....
And even then the achromat would have to be perfect to do so.

regards
Chris


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johnnyha
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: t.r.]
      #5476828 - 10/18/12 12:09 PM

I read that Terence Dickinson CT152 review as well t.r. I take those claims with a grain of salt. CT appears to be one of the leading advertisers in his magazine, in fact they have a prominent ad on the Sky News main web page. So Terence Dickinson receives advertising dollars from CT = by definition, not a 100% unbiased review.

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bobhen
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: johnnyha]
      #5476859 - 10/18/12 12:24 PM

“Maybe” at 180x, but try 480x. A high-end 6-inch Apo will easily deliver 80x per inch (or more) on Saturn (480x) and remain razor sharp in good conditions - a 5-inch 400x. Just as at low powers, the “effects” of CA are perceived to be lessoned when deep sky viewing, the same is true when planetary viewing. Testing planetary performance at higher powers will separate the men from the boys - as it does with any optical system.

Bob


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Jan Owen
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: bobhen]
      #5477468 - 10/18/12 05:47 PM

I don't know of anyone who is thinking this is a lunar/planetary scope...

With minus violet filter, it may be capable of showing an acceptable lunar/planetary image, but that's not the real purpose of this scope... It's a deep sky/wide field scope, and is capable of quite good performance in that mode, with magnifications below 100X (yes, I know, it may be capable of performance well above this level, but that's not it's intended niche)...

The concerns that bubble forth about CA, and so on, are mostly because some folks don't seem to understand the primary purpose of the scope, or who are being needlessly concerned that is is somehow a threat to their apo...

This scope was never designed to threaten apos, or to go head to head with them, so folks should quit being nervous!

Edited by Jan Owen (10/18/12 10:12 PM)


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johnnyha
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Jan Owen]
      #5477534 - 10/18/12 06:29 PM

Quote:

All the rest of the histrionics that bubble forth about CA, and so on, are just folks who either don't understand the purpose of the scope, or who are somewhat psychotic about it somehow being a threat to their beloved APOs...

This scope was NEVER designed to threaten APOs, so folks need to quit wetting their pants!



Nah, I'm pretty sure that's not it Jan. This scope is NOT a threat to any real APO - and I doubt any experienced astronomer thinks so. It fits a niche. I believe the discussion is more about setting the record straight on what even the finest made 6" f6 achro physically can and cannot do.

The psychotic ones, the threatened ones, and I thought it was clear from this thread , are the ones who are insisting over and over that this scope has no CA and being darn silly about it.


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chboss
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Jan Owen]
      #5477571 - 10/18/12 07:05 PM

Exactly right Jan, this is a scope that fills its nice nicely, which is widefield deepsky sweeping. No more, no less so I wonder where other claims come from...

best regards
Chris


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Jan Owen
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: johnnyha]
      #5477572 - 10/18/12 07:05 PM

...and my point is, that, for it's primary task, CA isn't even an issue, so why do we spend so much time discussing it???

There will be none (ZERO) visible on virtually any object that I'd be using it on...

The meaningful acceptance criteria for me isn't about CA; it's about how it presents the deep sky objects it'll be used on... And those objects, in my case, won't display any CA with this scope.

I know that's not the criterion many folks seem driven to apply to any scope, but that's what's applicable to this scope for my purposes...

Folks who want apochromatic performance shouldn't even be thinking about achromats. They should be doing critiques on apos... A discussion about a fast achromatic refractor isn't a place to be posturing about how much CA there will be on the moon or Jupiter at 400X... There'll be plenty. But I wouldn't be pointing it at the moon or planets. I have other scopes much better suited for that.

Edited by Jan Owen (10/18/12 10:19 PM)


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t.r.
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Jan Owen]
      #5477601 - 10/18/12 07:18 PM

Quote:

It fits a niche. I believe the discussion is more about setting the record straight on what even the finest made 6" f6 achro physically can and cannot do.



Bingo!


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johnnyha
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Jan Owen]
      #5477604 - 10/18/12 07:19 PM

Jan I read back through the entire thread.. There is an organic side conversation going on about CA within a discussion about the RFT qualities of this scope... and absolutley no bedwetting or "endless discussions" of CA that I can find?

OTOH I have to admit - - I misremembered it, I could not find anyone insisting over and over that there was absolutely no CA at all...

As I see it there were a few threatened by the honesty of Jim's review and that's about it, seems like a perfectly normal CN discussion to me.


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Rich
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: johnnyha]
      #5478099 - 10/19/12 12:55 AM

There have been recent threads claiming minimal CA for this scope, and getting excited when anyone challenged it, so I appreciate this review.

It does seem there are not enough ways to describe deep sky qualities of a scope as there are for planetary, or perhaps the descriptions don't come through as clearly as a declaration of CA level.


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Rich
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Mark Costello]
      #5478110 - 10/19/12 01:02 AM

Quote:


When it's at its closest, Mars is tougher or at least seems that way than Jupiter and Saturn. A while back I estimated that its intensity would be a little higher (light output per cross section area) which might be a reason for this.




Thanks for mentioning this. I've always been bothered more by CA on Mars than any other planet even though it is not the brightest. I've always assumed it was due to the color fringing being a bad color combination with the planet, and perhaps that still is true, but the intensity (surface brightness?) never came to mind. Probably a big factor.


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doctordub
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Rich]
      #5478412 - 10/19/12 09:01 AM

With a Baader semi Apo filter Jupiter was sharper at 450X than at 400X in my 8" Meade SCT. With a Chromacor 450X is sharp when viewing Saturn, Mars, and the Moon. I am anxious to try the Chromacor on Jupiter. This is definitely a Planetary Scope even without the Chromacor if you get one with excellent correction like mine, and there seems to be many good samples out there. When I get a chance I will be shooting some lunar shots with my TV Big Barlow.
CS
Jonathan


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Jim Romanski
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: jrbarnett]
      #5479060 - 10/19/12 03:50 PM

Jim

Thanks for the honest and entertaining review.

I’ve been looking at the AT 152 and the ES 152 scope and wondering just how good such inexpensive 6” refractors can be.

I’ve got an NP127 which I bought for its versatility. It’s a true rich field scope effectively free of CA that works just as well at high power and is great for imaging.

But aperture fever is not limited to the world of reflectors and the lure of a 6” refractor pulls on me.

I read the reviews from Terence Dickinson and the two in ATT and while false color is mentioned it seems to get brushed aside by all three reviewers quite easily. I believe one of the reviews didn’t even think the scope had much field curvature (how can that be?).

I’ve spent a lot of time looking through some older quality achromatic scopes specifically a 10” F/13 Clark and an 8” F/15 Grubb/Parsons. The Clark has noticeably more CA than the Grubb but at F/13 it’s quite tolerable and the views through both scopes are fantastic. But Crown and Flint can only do what Crown and Flint can do. Accordingly, the laws of physics tell me that a 6” F/5.9 scope should have LOTS of CA and I don’t see that this will vary from one scope to another by much. What is more likely to vary are people’s perceptions of CA and their tolerance of it.

How about field curvature? I don’t see how such a scope would not also have noticeable field curvature which is pretty easy to test for.

Terence Dickinson compares the aesthetics of the view of Saturn between the AT152 and his Astro-Physics 155. He doesn’t mention how they compare in detail but rather mentions that the 6” Achro had more detail than an unidentified 5” Apo he looked through. I sure wish he would have written more about the optical comparison. How did the views compare optically off axis? How did the views compare optically with the Astro-Physics?

Your review sounds more along the lines of my expectations and I find myself taking the other reviews with a large grain of salt in terms of CA.

And while using color blocking filters can improve the views through an achromatic refractor it is not the same as color correction.

I suppose this all gives me pause as to whether I’d really use such a scope when I have a nearly color free 5” scope already. But oh that aperture fever…


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Mark Costello
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Jim Romanski]
      #5479165 - 10/19/12 05:26 PM

Hi Jim. Speaking just from my own personality (use what I have) and not being experinced in either the NP127 or any 6" achro, if I had the NP127, I'd resist the urge to get a 6" achro, no matter how strong the urge or how good the achro (CA notwithstanding)....

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jrbarnett
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Jan Owen]
      #5479284 - 10/19/12 06:41 PM

"...and my point is, that, for it's primary task, CA isn't even an issue, so why do we spend so much time discussing it???"

Perhaps because reviews and forum posts indicating otherwise (i.e., that the scope is relatively or entirely color free on bright targets and at higher magnifications) are so plentiful and perhaps, even, predominant?

In line with your expectations and my original conclusion, this scope has plentiful false color and is better used for low power wide field DSO observing than for targets that typically receive higher magnifications.

I'll add, though, that a minus violet filter works well on this scope if you plan on using it on bright targets at higher magnifications. So even then, it's got utility and the capacity to deliver some pleasure.

But you're right - if you use it as you suggest, I think you'd like it. If we lived closer together I'd let you borrow mine for a few nights to see what you think.

Regards,

Jim


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Lane
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Mark Costello]
      #5479299 - 10/19/12 06:52 PM

If you want to use this scope on Planets I suggest the Baader Semi Apo filter. I have found that it knocks out about 50% of the CA and increases contrast much better than any other filter I have used so far. The remaining CA does not wash out planetary features at all, in fact I like the view better than my C8 because it seems to be sharper.

But as others have pointed out, this is not really meant to be a planetary scope, it is a widefield scope that you would use along side your main telescope. This is not a good scope to use under light polluted skies either, you should be prepared to take it to the dark where its puts up some very impressive views of nebula, galaxies, and clusters. Bright stars do show CA but I don't spend a huge amount of my time viewing bright stars and I don't think many other people do either. I do like to view double stars sometimes and most of the ones I have viewed so far with this scope were not bright enough to show any CA at all, plus they are much prettier in here than in my C6, C8, or C11.

Having also used the ES 6" scope I can say I definitely prefer this one optically but that one for its build quality. As far as the C6 SCT goes, that is a fantastic little scope, but I have put them side by side in a dark location more than once now and this achro to my eyes is brighter and the field of view is gigantic compared to the C6. The colors of double stars look more accurate to me in this achro as well and they appear to be sharper.

If you are looking for your first scope, this is not it. I would recommend an 8" SCT or one of the new HD or ACF versions that have the flatter field of view. That is a better choice for a lot of reasons including the fact that it will work on a small mount and this achro with not. I got this scope mainly to have a wide field of view with more light gathering and resolution than my other short focal length scopes. Plus I did not want to spend a small fortune for a 6" APO.

Knowing what I know now, would I still buy this scope? Even after I had to spend hours removing and redoing the felt on the dew shield to get it to fit and work correctly.
The answer is yes, I would buy it again, because it does the job I bought it to do.


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Mike4242
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Lane]
      #5479551 - 10/19/12 09:45 PM

Here's a pic of the moon I took about 30 minutes ago through my ES AR152 by holding my cell phone up to the EP. It was an ES 82 6.7mm yielding 147x. The CA seen on the limb of the moon in this picture looks a little more intense than it looked when actually looking through the EP; probably because the picture blows up the scale a little. Also, the pic is a little out of focus because I was having a hard time holding the phone still.



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johnnyha
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Mike4242]
      #5479568 - 10/19/12 09:56 PM

Thanks. The phone lens could also be responsible for a bit of it. There is quite a bit of CA along the terminator as well and in fact the entire surface shows purplish CA to my eyes, it's clear compared to the white space in the address window of my web browser.

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Mike4242
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: johnnyha]
      #5479575 - 10/19/12 10:02 PM

Other than the limb, the only CA I can see is in a few craters along the terminator. Doesn't bother me at all when at the EP. My actual target for tonight was Jupiter, but the darn clouds rolled in on me. I got a Baader Semi-apo in the mail today, but I haven't tried it yet. I wanted to compare Jupe with and without the filter. Maybe tomorrow tonight.

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Mike4242
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Mike4242]
      #5479583 - 10/19/12 10:08 PM

After closer inspection, it does look like some of the maria may have a little bit of violet hue. I think the camera being out of focus may be contributing a little.

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Tank
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Mike4242]
      #5479604 - 10/19/12 10:22 PM

Compared to a CA free scope the ACHRO will show the moon in a purple haze

Mine 150mm F5 at 75x the moon starts to show CA
Bright star show CA at 26x slightly


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johnnyha
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Tank]
      #5479649 - 10/19/12 10:51 PM Attachment (52 downloads)

If you scale it down a bit it's not that bad. Here it is side-by-side with the same shot but the color removed by the computer

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Mike4242
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: johnnyha]
      #5479666 - 10/19/12 11:00 PM

It definitely doesn't look as bad scaled down. The purplish tint in the maria and on the crater rims is more obvious comparing it to the processed image.

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doctordub
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Mike4242]
      #5480123 - 10/20/12 10:18 AM

Looks like about the same amount of CA as my image. Maybe you should start looking for a Chromacor, because the Raycor from Istar keeps getting delayed.
CS
Jonathan


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doctordub
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Tank]
      #5480141 - 10/20/12 10:28 AM Attachment (37 downloads)

Quote:

Compared to a CA free scope the ACHRO will show the moon in a purple haze

Mine 150mm F5 at 75x the moon starts to show CA
Bright star show CA at 26x slightly




Unless you use a Chromacor.
CS
Jonathan


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doctordub
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: doctordub]
      #5480142 - 10/20/12 10:30 AM

You will get a little less off axis color than above image this was spaced at 121mm, visually I use about 140mm.
Cs
Jonathan

Edited by doctordub (10/20/12 10:31 AM)


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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: doctordub]
      #5480144 - 10/20/12 10:34 AM Attachment (53 downloads)

Another image the same night.
CS
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Eric Gage
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: doctordub]
      #5480410 - 10/20/12 01:33 PM

I do see a little yellow/green on the limb in your pictures, Jonathan, but it is definitely an improvement.

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idealistic
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Eric Gage]
      #5480478 - 10/20/12 02:13 PM

Thats the moons atmosphere.

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johnnyha
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: idealistic]
      #5480695 - 10/20/12 04:54 PM

The Moon's atmosphere, or the Earth's?

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doctordub
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: johnnyha]
      #5480701 - 10/20/12 05:07 PM

You will see some blue in the crater shadows of the lower part of the image. The Moon is 0.5 degrees TFOV and you will see some off axis CA visually as well. The Chromacor spacing was at 121mm which is not the optimal spacing as well.
CS
Jonathan


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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: jrbarnett]
      #5480717 - 10/20/12 05:22 PM

Cavalry, Jim, not calvary. Calvary is some hill in Jerusalem.

Good review though. Anyone not expecting a ton of false color in a 6" f/6 achromat either inhabits a dream world or has a pair of those old man yellow filters installed in his eyes.


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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: jrbarnett]
      #5480728 - 10/20/12 05:29 PM

Your comments are appreciated and true, basically.

Where I diverge is, that, in my use of this scope, I'd virtually never go above 60X. I'd never look at a lunar landscape or a planetary image at any magnification... And I spend little time splitting double stars.

I'd be using it almost purely for star clusters, and other dim fuzzies within it's light grasp (I have other scopes that can deal with any unlikely urge to look at the moon or planets, and if I want to look at distant galaxies, and other equally dim stuff, I have other scopes capable of doing a better job there, too).

For the objects I'd be looking at, there's not going to be any CA. None.

There may be some field curvature, but I can't seem to get anyone to deliver any specific data about that. I even tried to pin Ed Ting down on that one in direct correspondence, given his review of this same basic scope, but he was reluctant to talk details about the edge performance... And many others who mention edge performance discuss it in terms similar to many who grew up not paying attention to edge performance, mostly because it wasn't AVAILABLE, so they quit looking for it... That seems to be where way too many folks are, whose experience I would expect more from... They haven't seen great edge performance because, for the most part, it hasn't been there, and so they don't even talk about it...

This has become so prevalent that Celestron is in the driver's seat now with the EDGE series. But I don't even think most folks fully appreciate what the EDGE delivers...

Thanks to the Paracorr, I can see this kind of edge performance in my Newtonians, yet others talk about not being bothered with coma in f/4.5 Newtonians... It isn't because coma isn't there; they've quit LOOKING for it (so it isn't there - fail).

We're probably not going to see perfection in a telescope anytime soon; and certainly at a reasonably low price... Top quality apos get awfully close from a performance standpoint. So does the EDGE. What *I'm* looking for is a low power refractor with some of the same characteristics as these other scopes, at an affordable price... If none appears, I'll just grab an EDGE...


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doctordub
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Jan Owen]
      #5480784 - 10/20/12 06:19 PM

Jan,
my eyes accomidate well so I don't notice field curvature in this scope with a 21mm Ethos.
CS
Jonathan


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Jan Owen
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: doctordub]
      #5480868 - 10/20/12 07:26 PM

I don't doubt that; but I'm an old fart. My eyes aren't able to deal with accomodation as well as they did back in the last century... So, I'm always looking to see how new scopes do in this regard... We humans, even old ones, manage it better than a camera does. But the older we get, the worse it becomes... Heheheh!!!

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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Joe Bergeron]
      #5480895 - 10/20/12 07:48 PM

Joe, I'm sorry if I wasn't clear, but I meant that the Savior intervened and sent bugle-blowing cherubim to intercede on my behalf with a minus violet filter in tow. In fact, given that divine provenance of this particular filter, I fully anticipate that it will be come the object of epic quests for ages to come.

- Jim


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galaxyman
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: stevew]
      #5481257 - 10/21/12 12:38 AM

Quote:

Quote:

Here's a dirty little secret - the C6's images are actually a little brighter and on clusters and at like magnification (~88x in each) it goes a little deeper to boot.

Regards,

Jim



Very curious.....




That is interesting, though side by side DSO observing between my ES 6" f/6.5 and a high quality 6" APO showed DSO's (planetary nebula, galaxies, and globs) in image brightness fairly close with the APO presenting (as it should) the better overall view per the review. The owner of the APO (very green observer) thought much of the time the views were nearly identical.

The CAS seasoned observers that were there saw what I was seeing. The APO as the superior scope, though at nearly 10 times the cost it better be.

I guess my point would be that a C6 would not be the equal of a high end 6" APO in image brightness. The other possibility is my particular ES 6" is a bit better than Jim's AT 6" example?

From very good dark sites my current 6" refractor has caught galaxies near 13.5 mag., so a good 6" achro can go deep when pushed.

Would like to hear from other owners of the AT 6" f/5.9 on pushing the scope on DSO's as in planetary nebula and galaxies.



Clear Dark Skies


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Chesmont Astronomical Society - www.chesmontastro.org
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TMB/APM 8" f/9 Refractor”The Beast”. One great DEEP SKY achro
ES 6" f/6.5 achro. Good one
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: galaxyman]
      #5481647 - 10/21/12 09:53 AM

Got a chance to view Jupiter last night with the AR152 and a Baader Semi-Apo filter. I was at our club's dark site and the guy that set up next to me had an EON. All I can say is that with a good CA filter these scopes can indeed be used as planetary scopes. The owner of the EON actually said he thought he was seeing more detail on Jupiter in the AR152. I disagreed though. While it did look much much better than I had ever hoped for in the AR152, the EON was putting up a more contrasty image with richer colors. There was one smaller thin belt south of the main SEB that I could see a little bit easier in the EON. I could see the same belt in the AR152, but it was a little more washed out looking. However, there were a few festoons in the NEB and SEB that were easier to see in the AR152. The color in the AR152 was more of a cooler whitish color while the EON showed nice rich warm color tones. The purple fringe was there in the AR152, even with the semi-apo filter, but it did not intrude onto the planet's disk to my eye.

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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: galaxyman]
      #5481715 - 10/21/12 10:47 AM

Yeah. Or it could be that I didn't roll out the C6 until after I got home, and the targets compared were higher and therefore embedded in less atmospheric glow, as I suggested earlier when asked about the apparent brightness difference mentioned originally.

I will put them side-by-side at some point, and throw in a C8 ($799 new as an OTA) for giggles, too. The optics on the AT152 aren't its problem. They are quite good, also as I reported in the original post. It's the physics that limit its potential, I suspect, as it is with any scope design really.

Regards,

Jim

Edited by jrbarnett (10/21/12 10:48 AM)


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galaxyman
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: jrbarnett]
      #5481868 - 10/21/12 12:21 PM

Quote:

Yeah. Or it could be that I didn't roll out the C6 until after I got home, and the targets compared were higher and therefore embedded in less atmospheric glow, as I suggested earlier when asked about the apparent brightness difference mentioned originally.

I will put them side-by-side at some point, and throw in a C8 ($799 new as an OTA) for giggles, too. The optics on the AT152 aren't its problem. They are quite good, also as I reported in the original post. It's the physics that limit its potential, I suspect, as it is with any scope design really.

Regards,

Jim




Hi Jim

Understand.

I'm guessing an estimate of overall light loss in the C6 is around 25% with coatings (though good), CO, and slight loss of aperture (150mm to 152mm).

I do think for the money it's a crapshoot, and though for some they like the AT over the ES with the shorter 6" achros. I personally wouldn't trade my particular ES 6" for the AT 6", for cost it wouldn't make sense, and my ES just may be a particular good one. Hard to say without seeing through say five or more for comparison. We do have another in the CAS, but we haven't had them side by side.

I will admit that down the road I will upgrade to a 6" ED (like the new APM). The other two achros ( APM 8" and the Celestron 4") are staying in my collection, with the 8" for certain


Clear Dark Skies


Karl
E.O.H.


Chesmont Astronomical Society - www.chesmontastro.org
Galaxy Log - http://www.youtube.com/user/GalaxyLog4565?feature=mhee
Telekit (Swayze optics) 22" F/4.5 Dob
Homemade (Parks Optics) 12.5" F/4.8 Dob
TMB/APM 8" f/9 Refractor”The Beast”. One great DEEP SKY achro
ES 6" f/6.5 achro. Good one
Celestron Omni XLT 102 refractor.
Celestron 10x60mm Binos


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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: galaxyman]
      #5484670 - 10/23/12 01:17 AM Attachment (64 downloads)

This has been a very interesting thread, given that I am receiving day after tomorrow my Teleskop Service 152mm (another variant of the Kumming Optics unit).

I am on a strict diet of DSO hence not worried about chromatic aberrations.

Jim, I read many reviews of the 152mm scope on this forum and yours appears to be the least biased of all, highlighting both the positive and negative attributes of this scope.

To claim (as done on other posts) that a Fraunhofer Achromat is color free on planets and moon is pushing into the realm of SF.

An extract from “Choosing and using a Refracting Telescope” by Dr Neil English (Part of Sir Patrick Moore’s Practical Astronomy Series)sums it up pretty nicely in 3 short paragraphs why color will always be evident in an achro:

"Modern achromatic doublet objectives are designed to bring two precise wavelengths (colors) of light to a common focus – red (656 nm corresponding to the Fraunhofer C spectral line) and blue green (486 nm corresponding to the Fraunhofer F spectral line).

In a contemporary C-F corrected achromat, colors lying outside this range of wavelengths (called the C-F focus) remain unfocused. These include deep red at one end of the spectrum and violet at the other. But that’s not a big problem. Fortunately, the human eye is not terribly sensitive to either of these radiations, and for the most part the position of C-F focus imparts a very natural color to the image.

In an ideal objective, all wavelengths between the C (red) and F (blue-green) Fraunhofer lines ought to be brought to a single focus, but in practice there is some color spread in the final image. This is what opticians call secondary spectrum and is the origin of the false color (chromatic aberration) seen in almost all achromatic refractors".

But, for my meatetarian diet of DSO, I say bring it on!

For those interested, I attach the bench test of the scope (Ronchi & diffraction rings).


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Cotts
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Mike4242]
      #5484927 - 10/23/12 09:22 AM

Quote:

Got a chance to view Jupiter last night with the AR152 and a Baader Semi-Apo filter. I was at our club's dark site and the guy that set up next to me had an EON. All I can say is that with a good CA filter these scopes can indeed be used as planetary scopes. The owner of the EON actually said he thought he was seeing more detail on Jupiter in the AR152. I disagreed though. While it did look much much better than I had ever hoped for in the AR152, the EON was putting up a more contrasty image with richer colors. There was one smaller thin belt south of the main SEB that I could see a little bit easier in the EON. I could see the same belt in the AR152, but it was a little more washed out looking. However, there were a few festoons in the NEB and SEB that were easier to see in the AR152. The color in the AR152 was more of a cooler whitish color while the EON showed nice rich warm color tones. The purple fringe was there in the AR152, even with the semi-apo filter, but it did not intrude onto the planet's disk to my eye.




About the purple fringe 'not intruding onto the planet's disk': The purple fringe does intrude and that is whole problem. Every part of the disk is producing its own little diffraction pattern, complete with purple fringe. The diffraction patterns collectively form the image you see and the purple is right there with them. The purple is only bright enough to see against a black background so the planet seems to be 'surrounded' by a purple ring when, in fact, it is completely covered with it, reducing contrast.

Dave


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dlapoint
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Cotts]
      #5485009 - 10/23/12 10:26 AM

excellent review. I was wondering how the ca compared to a 5" f6.5 ar?

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jrbarnett
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: dlapoint]
      #5485068 - 10/23/12 11:09 AM

I have me a good buddy, CNer cuzimthedad, who has an Antares 6" f/6.5. Mayhaps he and I will get the Astrotelescopes f/5.9 and Antares f/6.5 out at the same time, and see for ourselves how the two compare.

I wanted an excuse to go bug Dan and borrow his field on December 21st, anyway, weather permitting. It's only fitting that I use a big, fast crown & flint achro to observe the approaching cosmic doom on Mayan Apocalypse night. An odd scope on an odd night. But then again, we are the "Off Fisher Lane IRREGULARS" after all.

Regards,

Jim


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Mike4242
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: dlapoint]
      #5485244 - 10/23/12 01:02 PM

Quote:

About the purple fringe 'not intruding onto the planet's disk': The purple fringe does intrude and that is whole problem.




Good point. I'm sure it's reducing the contrast, but to the eye the planet itself doesn't look purple, which would be really annoying. I've seen photos of Jupiter through achros and the planet itself looks purple in the photos.

However, even though the CA does reduce contrast, and you may be missing some planetary detail in the achro, that doesn't mean you can't enjoy what is visible. If you're primary interest is seeing the maximum amount of low contrast planetary detail, then an ED or apo is definitely the way to go. But I don't think it makes sense to say flat out that these scopes can't produce nice views of planets. Not apo nice, but not that bad either.

After reading all of the forum posts about how these scopes are terrible at planets, I expected a horrible view when I looked through the EP, but was greeted instead by a pretty darn nice view of Jupiter.


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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Cotts]
      #5485387 - 10/23/12 02:23 PM

Quote:

About the purple fringe 'not intruding onto the planet's disk': The purple fringe does intrude and that is whole problem. Every part of the disk is producing its own little diffraction pattern, complete with purple fringe. The diffraction patterns collectively form the image you see and the purple is right there with them. The purple is only bright enough to see against a black background so the planet seems to be 'surrounded' by a purple ring when, in fact, it is completely covered with it, reducing contrast.




a little context is perhaps needed here. neil is correct that in normal situations the eye is relatively insensitive to spectral wavelengths below ~460nm. however light in that region is very potent. the filtering is mostly due to the atmosphere and yellow pigmentation in the lens and retina, yet violet light has over 30 times the impact on color perception as an an equal quantity (irradiance) of red or green light. and violet or purple mixtures are among the most chromatic (saturated, intense) colors we experience -- they "jump out" far more than a yellow or green hue. it is deceptive to downplay the importance of violet light in color vision.

in addition, both lightness contrast and edge detail are perceived through the R and G cones exclusively. to the extent that planetary detail is perceptible at all, the B cones have no part in it. since violet light is not focused on the retina when a yellow light image is in focus, it seems to detach from and hover around the in focus image. this effect is just as distracting when seen against a bright background, for example by looking at the sidewalk through a prism. and note that the eye adds its own violet defocus to the defocus native to an achromat.

light wavelengths outside the sensitivity range of a receptor cannot "obscure" the receptor response, no more than xrays or microwaves can obscure your perception of sunlight. however the R and G cones respond to wavelengths across almost the entire visible spectrum, so defocus in extreme wavelengths would have some (very small) effect on image clarity, separate from a perceptible "violet" tint. this is different from the question whether a defocused violet tint is perceptible at all and whether it is distracting.


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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: drollere]
      #5485700 - 10/23/12 05:20 PM

Great points, Bruce.

There's no coincidence that the Emperors of Rome chose purple for their state raiment (the "trabea"). Needless to say, they wanted to be noticed, no "shrinking violets" that lot (yeah, sorry, bad pun).

- Jim


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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: nicknacknock]
      #5491629 - 10/27/12 12:22 PM

Quote:

This has been a very interesting thread, given that I am receiving day after tomorrow my Teleskop Service 152mm (another variant of the Kumming Optics unit).

I am on a strict diet of DSO hence not worried about chromatic aberrations.

Jim, I read many reviews of the 152mm scope on this forum and yours appears to be the least biased of all, highlighting both the positive and negative attributes of this scope.

To claim (as done on other posts) that a Fraunhofer Achromat is color free on planets and moon is pushing into the realm of SF.

An extract from “Choosing and using a Refracting Telescope” by Dr Neil English (Part of Sir Patrick Moore’s Practical Astronomy Series)sums it up pretty nicely in 3 short paragraphs why color will always be evident in an achro:

"Modern achromatic doublet objectives are designed to bring two precise wavelengths (colors) of light to a common focus – red (656 nm corresponding to the Fraunhofer C spectral line) and blue green (486 nm corresponding to the Fraunhofer F spectral line).

In a contemporary C-F corrected achromat, colors lying outside this range of wavelengths (called the C-F focus) remain unfocused. These include deep red at one end of the spectrum and violet at the other. But that’s not a big problem. Fortunately, the human eye is not terribly sensitive to either of these radiations, and for the most part the position of C-F focus imparts a very natural color to the image.

In an ideal objective, all wavelengths between the C (red) and F (blue-green) Fraunhofer lines ought to be brought to a single focus, but in practice there is some color spread in the final image. This is what opticians call secondary spectrum and is the origin of the false color (chromatic aberration) seen in almost all achromatic refractors".

But, for my meatetarian diet of DSO, I say bring it on!

For those interested, I attach the bench test of the scope (Ronchi & diffraction rings).




I would love to see that done with a green filter or OIII
CS
Jonathan


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stevew
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: nicknacknock]
      #5491806 - 10/27/12 02:53 PM

Nicos, thanks for showing the test for your scope.
I'm not sure why anyone would think a large fast achromat would not have any chromatic aberration.
However your test does show the real strength of this scope, a smooth and well polished figure that helps it produce the sharp images that most owners rave about.

Steve


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doctordub
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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Cotts]
      #5492804 - 10/28/12 09:38 AM

Quote:

Quote:

Got a chance to view Jupiter last night with the AR152 and a Baader Semi-Apo filter. I was at our club's dark site and the guy that set up next to me had an EON. All I can say is that with a good CA filter these scopes can indeed be used as planetary scopes. The owner of the EON actually said he thought he was seeing more detail on Jupiter in the AR152. I disagreed though. While it did look much much better than I had ever hoped for in the AR152, the EON was putting up a more contrasty image with richer colors. There was one smaller thin belt south of the main SEB that I could see a little bit easier in the EON. I could see the same belt in the AR152, but it was a little more washed out looking. However, there were a few festoons in the NEB and SEB that were easier to see in the AR152. The color in the AR152 was more of a cooler whitish color while the EON showed nice rich warm color tones. The purple fringe was there in the AR152, even with the semi-apo filter, but it did not intrude onto the planet's disk to my eye.




About the purple fringe 'not intruding onto the planet's disk': The purple fringe does intrude and that is whole problem. Every part of the disk is producing its own little diffraction pattern, complete with purple fringe. The diffraction patterns collectively form the image you see and the purple is right there with them. The purple is only bright enough to see against a black background so the planet seems to be 'surrounded' by a purple ring when, in fact, it is completely covered with it, reducing contrast.

Dave




I agree Dave, which is why I believe the scope snaps to focun with my Chromacor.
CS
Jonathan


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Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: dakota]
      #5494835 - 10/29/12 03:28 PM

I still maintain that this is a fantastic telescope for the money.

Enjoy Hans!


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Jan Owen
Pooh-Bah


Reged: 02/12/06

Loc: Sun City West, Arizona
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: thesubwaypusher]
      #5494847 - 10/29/12 03:34 PM

Hope you're riding out the storm (Sandy) safely... Take care!!!

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Jan Owen
Pooh-Bah


Reged: 02/12/06

Loc: Sun City West, Arizona
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: doctordub]
      #5494852 - 10/29/12 03:36 PM

Hope you're safe & on relatively high ground out of harm's way, while you ride out Sandy!!! Take care!!!

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dakota
sage
*****

Reged: 12/11/11

Loc: SD (God's Country)
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: thesubwaypusher]
      #5495110 - 10/29/12 06:23 PM

Quote:

I still maintain that this is a fantastic telescope for the money.

Enjoy Hans!



I'm just going to stay out of the bickering and negativity surrounding this scope. I love mine and couldn't be happier. While everyone is debating this and that I'm busy enjoying mine.


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johnnyha
Postmaster
*****

Reged: 11/12/06

Loc: Sherman Oaks, CA
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: dakota]
      #5495238 - 10/29/12 08:04 PM

It's nice to know these are very well made and have a nice figure and coatings on the optics, I think that's what is most important. The important thing should be how the Double Cluster looks, or M45 or M42, or globs like M13. In that regard it seems this scope is a winner!

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doctordub
Pooh-Bah


Reged: 01/11/06

Loc: New Rochelle, New York
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Jan Owen]
      #5496225 - 10/30/12 01:50 PM

Thanks Jan,
I just got my Internet back but I never lost power. I had a large branch break in my front yard, but there was almost no damage. I live on high ground, if my house floods its time to build an Ark!
CS
Jonathan


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Sean Puett
Carpal Tunnel
*****

Reged: 09/06/10

Loc: always cloudy, washington
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: dakota]
      #5496390 - 10/30/12 03:36 PM

Quote:

I don't recall accusing you of saying the dew shield was plastic. I don't recall the other reviewers saying the was no CA. Seems like you are the one twisting the facts mister.

Reread your initial review. Came out pretty strong with negatives. I didn't take anything personally. So no need to throw that barb into the discussion.

I have no problem with the balance. My lowly CG-5 handles this scope quite well. Just balance it properly and one is all set.

Again, this is your opinion which you are entitled to. So don't take it personally when someone doesn't agree with you.




Actually there have been many claims on cn that the CA was " minimal" or "better than expected". I am glad I didn't buy one myself but, I waited for Jim's review anyway. I had a 90mm f6.1 achro and the CA was horrible on bright objects and it just didn't make sense that a 6" f5.9 would be better, it should be worse. So I am glad I decided to wait. I really don't need another telescope anyway.

I took a break from CN so your review seemed very prompt to me Jim. Thanks for the honest kool aid free review.


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Sean Puett
Carpal Tunnel
*****

Reged: 09/06/10

Loc: always cloudy, washington
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Sean Puett]
      #5496444 - 10/30/12 04:18 PM

I forgot to add that you can keep your c6! I am a newt and refractor snob. I don't need perfect color correction but, purple Jupiter is no bueno.

I, if I decide to get a bigger refractor, am leaning more toward a vixen NA 140. I really need to try one first though. I am the guy who would have been upset when i bought the Astro telescope 6"f5.9 and saw the color i expected to be there because so many reviews minimized the CA reports. $1000 isn't the end of the world but, it is enough to make me unhappy with less than accurate reviews.


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dakota
sage
*****

Reged: 12/11/11

Loc: SD (God's Country)
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Sean Puett]
      #5496911 - 10/30/12 09:18 PM

Quote:

Quote:

I don't recall accusing you of saying the dew shield was plastic. I don't recall the other reviewers saying the was no CA. Seems like you are the one twisting the facts mister.

Reread your initial review. Came out pretty strong with negatives. I didn't take anything personally. So no need to throw that barb into the discussion.

I have no problem with the balance. My lowly CG-5 handles this scope quite well. Just balance it properly and one is all set.

Again, this is your opinion which you are entitled to. So don't take it personally when someone doesn't agree with you.




Actually there have been many claims on cn that the CA was " minimal" or "better than expected". I am glad I didn't buy one myself but, I waited for Jim's review anyway. I had a 90mm f6.1 achro and the CA was horrible on bright objects and it just didn't make sense that a 6" f5.9 would be better, it should be worse. So I am glad I decided to wait. I really don't need another telescope anyway.

I took a break from CN so your review seemed very prompt to me Jim. Thanks for the honest kool aid free review.




So what point are you trying to make?


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dlapoint
scholastic sledgehammer


Reged: 08/18/03

Loc: Moncton NB Canada
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: dakota]
      #5497048 - 10/30/12 10:57 PM

I just ordered the Canadian telescopes version of this scope, and was told they are going to be discontinued. I wonder if the same is true of the astrotelescope?

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thesubwaypusher
scholastic sledgehammer
*****

Reged: 07/08/04

Loc: New York City
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Jan Owen]
      #5497256 - 10/31/12 03:04 AM

Quote:

Hope you're riding out the storm (Sandy) safely... Take care!!!




Thank you Jan.

We were just hiding trains and buses. Now were just taking them out of their hiding spots.


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doctordub
Pooh-Bah


Reged: 01/11/06

Loc: New Rochelle, New York
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Sean Puett]
      #5497893 - 10/31/12 02:52 PM

Sean,
With CN and other AA websites I do not see where anyone would need to drink the “Kool Aid”, one can look at Nikos Star Test for SA and Polish, and my unprocessed single shot Lunar Image without Chromacor to see the Level of CA .
The only mention I have heard of no CA was for stars with Mag 3.5 or lower. When adjectives such as “better than expected” were mostly from individuals comparing Meade, Celestron and Synta 6” F8 Achros to one of the 152-F5.9 Kumming Scopes.
I agree with you on skipping the C6. If you want Planetary and Lunar performance in a smaller Cat get an Intes M703, or M715.
If I were you I would skip the Vixen 140 NA, it is more expensive than the AT 152 and not as sharp.
You could always wait for the Raycorr to be available and choise between Istar, D&G, and a Kumming Clone.
CS
Jonathan


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Lane
Post Laureate


Reged: 11/19/07

Loc: Frisco, Texas
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: doctordub]
      #5497953 - 10/31/12 03:24 PM

Or you could just pony up about 9 grand for a TEC 160, that will certainly eliminate the CA for you and it only cost 9 times as much as the AT152.

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doctordub
Pooh-Bah


Reged: 01/11/06

Loc: New Rochelle, New York
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: thesubwaypusher]
      #5498111 - 10/31/12 05:09 PM

Chris,
Be careful, those are subway cars not submarines. It is starting to feel like 2012, wait a minute, it is!
It’s like Florida without the Alligators, wait a minute I take that back to. Just be careful Chris.
CS
Jonathan


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Rich
member


Reged: 01/21/06

Loc: Seattle
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: doctordub]
      #5498822 - 11/01/12 01:13 AM

Quote:


If I were you I would skip the Vixen 140 NA, it is more expensive than the AT 152 and not as sharp.





Have you compared these two? What did you find in terms of the NA 140 not being as sharp? I've used an NA 120 a lot and found the images to be excellent, but perhaps there is something about the 140 that you found different?


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nicknacknock
professor emeritus
*****

Reged: 02/20/12

Loc: In a galaxy far far away...
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Rich]
      #5498975 - 11/01/12 07:27 AM

Well, I will wait for dark skies (when the moon gets out of the way) and try it out. I will come back with some honest feedback. Will spend some time on Jupiter, see how the Pleiades show up and then it's DSO for me. If you folks have a specific target you want me to report on, bring it on.

Location coordinates Latitude 34.815607, Longitude 33.321533 (give or take a few kilometers). Planning to be out hopefully 8th and 9th of November.

BUT...

Set up the scope a couple of times (practice for when I go to my preferred dark site) and took a peak at the moon (which was full).

Disgusting I tell you! Got blinded and the moon oh-so-big and purple-ish. So, I tossed in the minus fringe filter with my Ethos 13mm. very minor difference. Took the sucker out. Used a variable polarising filter. Major improvement. Double stacked polarising filter with minus violet filter. No improvement over just the polarising filter. Double stacked with a yellow filter and then a green filter. Mucho improvement in contrast (but only if you have a fetish for cheese / broccoli).

To cut a long story short. This scope ain't for planets, moon and bright targets. It is a short focal ratio wide field achro refractor. Get another scope if you want to optimize your viewing experience for such targets.


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doctordub
Pooh-Bah


Reged: 01/11/06

Loc: New Rochelle, New York
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: nicknacknock]
      #5499015 - 11/01/12 08:36 AM

Nicos,
one word "Chromacor". If you can't get one wait for the Raycorr from Istar. The Chromacor at a non optimal setting shows about the same CA as your SV102ED.
CS
Jonathan


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doctordub
Pooh-Bah


Reged: 01/11/06

Loc: New Rochelle, New York
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Rich]
      #5499021 - 11/01/12 08:43 AM

Rich,
I was going to purchase a Vixen NA140 about two years ago when I compared one to my TV102. I was not pleased with Lunar or Planetary views and the images just were not as sharp as I expected. I had a chance to compare it to an ES152 and the ES152 was much sharper.
CS
Jonathan


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jrbarnett
Eyepiece Hooligan
*****

Reged: 02/28/06

Loc: Petaluma, CA
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: nicknacknock]
      #5499298 - 11/01/12 11:58 AM

Nicos:

I wouldn't rule out all minus violet filters on the basis of trying just one.

The MV-20 from Sirius (no longer made) aggressively suppressed much of the false color on double stars at high magnification. I didn't try it on Luna, though, but will.

I think you have to look at the bandpass data for the MV filter in question (they differ model to model) and then the color crossings of this scope, in order to predict what MV filter would be optimal for the optic.

But as you say, if you plan on using it for DSOs and wide fields, I suggest M42 at ~100x, and reporting back on whether you could easily pick up Trapezium E and F. Context and resolution all at once. Should be sweet on that target.

Regards,

Jim


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nicknacknock
professor emeritus
*****

Reged: 02/20/12

Loc: In a galaxy far far away...
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: jrbarnett]
      #5500344 - 11/02/12 02:08 AM

@ Jonathan: Impossible to find a Chromacor and on the list for Raycorr since like 3 months ago.

@ Jim: Like the Chromacor, the MV-20 is one of those really hard to find items. I used a Baader minus fringe filter to see how it does on the moon. Will get back to you on M42 when the Gods of weather cooperate and someone shoots the moon out of the sky.

Clear skies,

Nicos


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RolandosCY
super member


Reged: 01/02/09

Loc: Nicosia, Cyprus
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: nicknacknock]
      #5500545 - 11/02/12 08:40 AM

Quote:

Location coordinates Latitude 34.815607, Longitude 33.321533 (give or take a few kilometers). Planning to be out hopefully 8th and 9th of November.



You think I will be waiting THAT long for setting up the 152 in between the FS102 and the 18"??? You must be kidding... Monday moonrise 10pm, good conditions expected!


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doctordub
Pooh-Bah


Reged: 01/11/06

Loc: New Rochelle, New York
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: nicknacknock]
      #5500652 - 11/02/12 10:14 AM

Nicos,
I understand your frustration. It took me 13 months to get a Chromacor. I am waiting like you to see what happens with the Raycorr.
CS
Jonathan


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jrbarnett
Eyepiece Hooligan
*****

Reged: 02/28/06

Loc: Petaluma, CA
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: nicknacknock]
      #5500730 - 11/02/12 11:15 AM

Nicos, I thought the sun always shined on Cyprus.

Just teasing you. I last visited in 1985 - in the summer - so my view is biased, I'm sure.

I worked for a year on a wheat farm outside of Thessaloniki, and took time off farming to travel Greece, Turkey, Crete, Cyprus, other minor islands, Lebanon and northern Egypt.

I'm sure Cyprus has changed a lot, but in 1985 it was pretty sleepy and very quaint. I think the holiday condo boom for Brits was a few years away at that time.

I have many happy memories from that part of the world.

Regards,

Jim


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nicknacknock
professor emeritus
*****

Reged: 02/20/12

Loc: In a galaxy far far away...
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: jrbarnett]
      #5500765 - 11/02/12 11:34 AM

@ Jim: Come over any time. No need to bring astrogear, I have enough for two!

@ Rolandos: Monday it is!

@ Jonathan: This Raycorr saga is never ending. I hope they release the dang thingies soon!


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RolandosCY
super member


Reged: 01/02/09

Loc: Nicosia, Cyprus
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: jrbarnett]
      #5501026 - 11/02/12 02:06 PM

Quote:

Nicos, I thought the sun always shined on Cyprus.

Just teasing you. I last visited in 1985 - in the summer - so my view is biased, I'm sure...
Regards,

Jim




Hi Jim, good to know that some Americans do visit our little corner of the world

Cyprus did change a lot, the last few years have seen a steady influx of wealthy Russians replacing the Britons. Unfortunately, more development means more light pollution. But there are positive changes: there are people now eith 16 and 18 inch dobs (three years ago a 12" was spectacular!), lots of refractor guys, some crazy people who test equipment all the time, and yes, the sun still shines a lot!

As Nicos said, you are welcome any time to visit again with astronomy in mind! And, by the way, congratulations on your reviews - the one on the AT 152 made me more anxious to test it than even Nicos who bought it!

Best regards from the island of Venus!

Rolandos


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nicknacknock
professor emeritus
*****

Reged: 02/20/12

Loc: In a galaxy far far away...
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: RolandosCY]
      #5506250 - 11/06/12 01:22 AM

OK folks, had some fun with the scope last night. To cut a long story short, only point this scope on Jupiter if it's Halloween and you are dressed the part.

@ Jim: Orion wasn't high enough by the time the moon reared its ugly head up last night to make a fair assessment on Trapezium E & F. Next time tho!

To add some gravy: The scope performs beautifully on DSO. Veil Nebula, North American Nebula and Orion Nebula show lovely textured structure.

NGC 253 and NGC 288, Double Cluster are quite enhanced vs my 4". Not that I expected any different of course.

At f5.9 field curvature makes itself apparent as with the Nagler 31 and with Ethos 21, there was a need for a touch of refocusing on the edge of the field vs center.

Pleiades: Jaw dropping. Nebulosity around the sisters clearly visible. Always envied what I saw in photos but it took Pig to show me in real time. Now I understand why people love the Pleiades. Sisters got a lot of character if you can see that beautiful ethereal texture around them. They are jewels indeed!

But back to the Halloween comment: Jupiter is fugly in this scope. Pardon my French but even though there is a lot of detail coming out, chromatic aberration clearly robs contrast and becomes annoying.

As the moon reared its ugly head, in one corner weighting 24 pounds was my TS152AR with a 8mm Ethos @ 113x. In the other corner weighting 6 pounds was my AT72ED with a 3.7mm Ethos @ 116x. Tiny Tim KO'd Pig in 2 seconds flat. No false color on the ED but with the AR, the moon resembled a nice piece of cheese both in color and texture.

The Achromat was also unable to compensate for the fact that the moon was low over the horizon, tossing in hues of green and blue and (insert favorite color) as the seeing wavered a lot. The ED scope was unaffected. Turbulence was evident due to the mon's position, but no false color and a more contrasty view.

Summary:

Buy this if you want an el-cheapo 6" refractor with fantastic contrast on DSO, nice sharp images for your choice of faint fuzzies, in a manageable package (manageable depends on many factors, but Pig is not that hard to set up).

Don't buy this if you want a planetary scope. ED or APO or SCT or MCT or Reflector will serve you better.

Me, I am happy overall. I got exactly what I wanted and exactly what I expected.


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RolandosCY
super member


Reged: 01/02/09

Loc: Nicosia, Cyprus
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: nicknacknock]
      #5506341 - 11/06/12 05:15 AM

I was with Nick last night. I had a high anticipation on observing through the 152 myself, no doubt one reason being this whole thread!

I have been using steadily two refractors in my astro career, a Tak FS102 and a Synta ED80. I have observed all planets (including the moon) and many of the best / brighest deep sky objects through both of these refractors, as well as through many reflectors from 4.5 to 18 inches.

Well...
M31 at the zenith was great. Quite bright, lots of low contrast detail with the dark lanes and faint outer regions of the arms well defined. Impressive.

Pleiades: Excellent framing with the 31 Nagler. The nebulosity around Merope was nothing sort of amazing. I would buy the scope just for this picture. But (yes, there is a "but"): I could detect easily purple around the brighest stars. I did not look for it. The color just showed itself. Obvious. Not detracting from the beauty of the image, but IT WAS THERE.

NGC 253 was detailed, quite bright, showing mottling on the core.

NGC 247 was visible with direct vision, and despite its faintness, some structure could be made out...

Gamma Andromedae: Nice double, but the fgaint companion was a bit "drawn" in the violet haze around the yellowish primary.

Jupiter: Man, the scope is not intented for planetary viewing. There was a lot of violet around the planet. The planet itself had a strange light yellow - lime cast on it without any filters. Low contrast. I had spent two hours observing Jupiter with the FS102 the previous night, and there was simply no comparison between the two - in the Tak Jupiter appeared with the same pure colors that were evident in my color-free 18" dob. Adding filters did diminish the violet, but it also enhanced the yellowish cast. Not for my taste.

The Moon: Although low, the color was again very evident. A major violet wash. The low altitude of the moon meant a lot of trembling of the image, and you could see craters immersed in violet and greenish color, especially at the shadow edges. Nothing of that sort was visible through the other scopes.

So, what do I think? The scope should not be on the list of anybody seriously considering a planetary scope. Also, people thinking about an "all-around" scope should be prepared that the 152 will not perform well on the moon and planets, or even on the brightest double stars. But, I did like its performance on most deep sky objects. Even the violet around the brighest Pleiads was not enough to detract from the beauty of the scene. North America nebula, Pelican, the area around Gamma Cygni, the Veil, M42 (even at its very low altitude) all were very very pleasing and beautiful in this scope. Being a deep-sky observer, had I had enough storage space at home, I would consider such a scope as a "grab and go" alternative for my 18" dob for shorter sessions. But for the moon / planets I would stick to my other two refractors...

Edited by RolandosCY (11/06/12 05:18 AM)


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Jan Owen
Pooh-Bah


Reged: 02/12/06

Loc: Sun City West, Arizona
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: RolandosCY]
      #5507311 - 11/06/12 05:59 PM

Thanks to both of you for taking the time to report your observations. Both were interesting and informative reports, and will be helpful to me as I continue to try to make a decision between several options in this aperture...

I'm sure these reports will be helpful to others, as well, adding to the value of this thread!

Sounds like you both had a good time, too!!! THANKS!!!


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jrbarnett
Eyepiece Hooligan
*****

Reged: 02/28/06

Loc: Petaluma, CA
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: Jan Owen]
      #5507406 - 11/06/12 07:05 PM

Jan:

If you haven't pulled the trigger before the Tucson show, and get a chance to look through that new APM 6" ED doublet, I'd love to hear your impressions of the scope.

Regards,

Jim


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jrbarnett
Eyepiece Hooligan
*****

Reged: 02/28/06

Loc: Petaluma, CA
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: RolandosCY]
      #5507458 - 11/06/12 07:45 PM

Are there any Aegean isles that are well-suited to astronomy from a light pollution perspective?

- Jim


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RolandosCY
super member


Reged: 01/02/09

Loc: Nicosia, Cyprus
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: jrbarnett]
      #5507874 - 11/07/12 02:57 AM

Quote:

Are there any Aegean isles that are well-suited to astronomy from a light pollution perspective?

- Jim



Jim, most of the smaller Aegean islands, and especially those away from the mainland coasts (whether to the east or west) should still be free of light pollution. But you should avoid islands that have become famous as tourist destinations (such as Kos, Santorini, Mykonos, Naxos). The Mediterranean is still acceptable as far as light pollution is concerned. Even on mainland Greece around the Pindus mts area you can get very dark skies. On our own island (Cyprus) we still get 21.3 sqm readings on "average" nights at sites within 40 minutes drive... Let us know if you think of coming over this area again...


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doctordub
Pooh-Bah


Reged: 01/11/06

Loc: New Rochelle, New York
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: RolandosCY]
      #5511907 - 11/09/12 03:57 PM

The sky has cleared up, I will get to use my Chromacor + AT152 vs Intes M703 on Jupiter!
CS
Jonathan


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fuzzystuff4ever
member


Reged: 11/26/12

Loc: Micco, FL
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: doctordub]
      #5552127 - 12/03/12 02:13 PM

The AT152 is a wonderful scope within it's limitations. My favorite pastime is to cruise the Milky Way with it and a Tak 50mm LE eyepiece.

Brian


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jrbarnett
Eyepiece Hooligan
*****

Reged: 02/28/06

Loc: Petaluma, CA
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: fuzzystuff4ever]
      #5552211 - 12/03/12 03:02 PM

"My favorite pastime is to cruise the Milky Way with it and a Tak 50mm LE eyepiece."

And that is a near perfect use of a richest field telescope (RFT). My favorite use is similar, though given that my maximum pupil dilation these days is just about 6mm, I tend to top out with a 34-35mm 68-70 degree eyepiece. Because the Astrotelescopes 152 is so fast, I find that well corrected wide fields like ES 68s and 82 and Naglers and Panoptics help maximize the well-corrected true field.

But yeah, it's a nice cruiser; like a 6" monocular.

- Jim


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fuzzystuff4ever
member


Reged: 11/26/12

Loc: Micco, FL
Re: Overdue First Light: Astrotelescopes 152 f/5.9 new [Re: jrbarnett]
      #5552400 - 12/03/12 04:54 PM

I don't have any wide-field long FL eyepieces, so have to use a (nice) 32mm Plossl or the 50 Tak. I almost fell off my chair the first time I "discovered" Kemble's Cascade; such an unbelievable sight.

Brian


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