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Equipment Discussions >> Refractors

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Pete-LH
sage
*****

Reged: 03/25/09

Loc: Wilmington, DE
"Planet Killer"
      #5943354 - 06/27/13 04:07 PM

Not crazy about this term but I see they have a $499 version of the SV 4" f11 with a single speed crayford and a $699 version still with the dual speed R&P. Are there any updated reviews on this refractor? I am tempted but already have four in the 90 to 102mm range.

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Binojunky
Carpal Tunnel
*****

Reged: 12/25/10

Re: "Planet Killer" new [Re: Pete-LH]
      #5943428 - 06/27/13 04:57 PM

Quote:

Not crazy about this term but I see they have a $499 version of the SV 4" f11 with a single speed crayford and a $699 version still with the dual speed R&P. Are there any updated reviews on this refractor? I am tempted but already have four in the 90 to 102mm range.




I know the feeling, been looking at that myself, also the single speed ED 80,DA.


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johnnyha
Postmaster
*****

Reged: 11/12/06

Loc: Sherman Oaks, CA
Re: "Planet Killer" new [Re: Binojunky]
      #5943439 - 06/27/13 05:04 PM

For the price you could kill planets lots better with a 10"-12" dob... I say this only because you already have four 4" class refractors and f11 isn't going to significantly change the planet destruction.

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KerryR
Post Laureate
*****

Reged: 12/05/07

Loc: SW Michigan
Re: "Planet Killer" new [Re: Binojunky]
      #5943450 - 06/27/13 05:10 PM

Personally, I consider 4" a little small for dedicated planetary observation.

On the other hand, seeing is far more likely to play nicely with a 4" than it is, say, an 8 or 10", which makes the 4"ers pretty ideal scopes for "average" conditions.

Sounds to me like you're already pretty well covered at that aperture, unless you feel the others have comparatively inferior optics.


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BillP
Postmaster
*****

Reged: 11/26/06

Loc: Vienna, VA
Re: "Planet Killer" new [Re: Pete-LH]
      #5943466 - 06/27/13 05:16 PM

One of the Celestron 6" f/8 Achromats likely a better choice as when you stop it down to 4" it is actually slightly better at f/11.9, and then when you open it to full aperture it of course is much better for DSO.

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belgrade
sage


Reged: 10/05/07

Loc: Frisco, TX
Re: "Planet Killer" new [Re: KerryR]
      #5943481 - 06/27/13 05:24 PM

Anyone knows what's difference between the SV's version for $499 and AT's version for $599 by Hands On Optics? It seems to me the AT's version is the same as the one by SV for $699? And btw, I can't believe that the price of AT's version keeps going up and up... I mean, we're still talking an achro here, either by SV or AT. Or they are really worth that much?! Please advise, I never used either. Thx.

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AstroSteve
scholastic sledgehammer


Reged: 08/17/04

Loc: Kissimmee, Florida
Re: "Planet Killer" new [Re: belgrade]
      #5943516 - 06/27/13 05:49 PM

"Planter Killer" I thought that was the Death Star in the Star Wars movies. Haha!

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Astrojensen
Post Laureate
*****

Reged: 10/05/08

Loc: Bornholm, Denmark
Re: "Planet Killer" new [Re: BillP]
      #5943528 - 06/27/13 05:54 PM

Quote:

One of the Celestron 6" f/8 Achromats likely a better choice as when you stop it down to 4" it is actually slightly better at f/11.9, and then when you open it to full aperture it of course is much better for DSO.




Not a bad suggestion. I use a 6" f/8 Sky-Watcher myself, which has a dustcap with a smaller aperture stop in the middle with its own cap. It has 4.5" free aperture and an f/ratio of 10.7, when used with the dust cap stop. Planetary performance is quite darn good and false color is very well controlled. Deep-sky is very impressive for a 6", when used at full aperture. Especially at low magnifications with modern 82° eyepieces.

But it is a big and heavy scope. An EQ-6 or similar mount, preferably larger, is almost mandatory. I've tried it on a Vixen GP and can't recommend it. It's fine on an EQ-6 with Baader tripod.

If a 4" refractor is needed, because a lightweight and quick setup is required, then a 6" f/8 achro is definitely not the way to go. Just sayin'.


Clear skies!
Thomas, Denmark


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Pete-LH
sage
*****

Reged: 03/25/09

Loc: Wilmington, DE
Re: "Planet Killer" new [Re: BillP]
      #5943542 - 06/27/13 05:59 PM

Actually, I try not to reveal my insanity ... But I also use a C9.25, C-8, 5" f/12 Superplanetary, 100mm f/13 Carton, 102mm Tak FS-102, 90mm FL90S, 90mm 90M f/11(also Vixen).

I guess in looking for sanity, my plan is to someday just have a 4" refractor and the C-8 which will be easy to set up in my olde age.

As I said I don't like the term "Planet Killer". On good seeing nights I may use the C9.25 or SP, and on nights when the seeing is not so good and I don't have much time to sit and ponder the wonders of the universe at leasure I set up a small scope and get some quick quality time in. And usually I waste too much time deciding which one to set up. And double stars and star clusters are typically my target although planets and DSO's are on the card as well.

Still I feel the refractor force.


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Pete-LH
sage
*****

Reged: 03/25/09

Loc: Wilmington, DE
Re: "Planet Killer" new [Re: belgrade]
      #5943550 - 06/27/13 06:04 PM

[Regarding the difference]

Probably should not have started another thread but the SV has a better focuser I believe, one or two speed now, the ability to shorten the tube for binoviewers and the "StellarVue" brand. I'm not sure $200 is warranted in going from 1 to 2 speed but I do prefer an R&P focuser.

There is a thread in April that describes all this.


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BigC
Carpal Tunnel
*****

Reged: 09/29/10

Loc: SE Indiana
Re: "Planet Killer" new [Re: Pete-LH]
      #5943573 - 06/27/13 06:19 PM

I suggest you consider a 120 f8.3 for your "olde age".

Keep the goto 8" SCT of course.


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Don Taylor
professor emeritus


Reged: 07/12/09

Loc: South TEXAS
Re: "Planet Killer" new [Re: belgrade]
      #5943961 - 06/27/13 10:55 PM

From what I can see on SV's website the $699 scope uses the Stellarview 2 speed r&p focuser which is a bit different than the long-perng r&p used on the hands on optics version, which is the version I have.

Originally the HOO version and the original Stellarview versions used the Kunming 2 speed Crayford, as some other versions of this scope still appear to. The original version of the HOO scope was $499 before the focuser was upgraded.

If its of any value, the long-perng rack and pinion works very well although I have not been able to compare to the 2.5" Stellarview focuser. There has also been some variation in the length of dew shield between the various versions available.

The scope is excellent btw.


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Mark Harry
Vendor
*****

Reged: 09/05/05

Loc: Northeast USA
Re: "Planet Killer" new [Re: BillP]
      #5944241 - 06/28/13 05:33 AM

Had the exact same idea with my 'in the works' 8" achro.(!)
Working on the crown lens now. Masked down, it'll be a 5" F/12.5~. A bit more ap than a 4; should make things interesting on planets, yet still has 8" of glass for DSOs.


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Niklo
professor emeritus


Reged: 03/29/13

Loc: Bavaria
Re: "Planet Killer" new [Re: Mark Harry]
      #5944318 - 06/28/13 07:17 AM

Hello Pete,
so you already have a 100mm f/13 Carton and a 102 Tak FS-102 so you have two very good 4" refractors.
The 4" f/11 really looks interesting and seems to be a good refractor but I expect that both the Tak and the Cartoon or at least the Tak is better.
So you needn't buy it but I can understand you. It's nice to compare telescopes, play with different ones and if it looks nice .... I feel that I tend to collect telescopes for that reason too.
Cheers,
Roland


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stanislas-jean
Carpal Tunnel


Reged: 10/22/08

Re: "Planet Killer" new [Re: Niklo]
      #5944328 - 06/28/13 07:29 AM

Personally I had now the RS100 Tal, last model, and the 120ED SW in hands, owned the vixen 100F10.
Lastly on saturn the 120ED and the tal 100 exhibited fine results but with actually no significant different results about the accessible features.
I have to compare this also on venus where the 100RS shows already fine banding structure on the atmosphere.
I donot agree with forumers here about the fact that 100mm aperture is confidential or too small.
This is with these kind of apertures that visual observers may train their vision with acurate optics in order to go deeper and deeper on a planet image.
I donot know what is this "planet killer" 100F11 but surely not outperforming what I tested already.
Stanislas-Jean


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Niklo
professor emeritus


Reged: 03/29/13

Loc: Bavaria
Re: "Planet Killer" new [Re: stanislas-jean]
      #5944397 - 06/28/13 08:40 AM

Hi Stanislas-Jean,
the Tal 100 RS is a nice and interesting 4" refractor, too. I was curious and started a thread. Comparing Tal 100 RS with TS 102 f/11.
It seems that have similar performance and it seems that the f/11 is a little bit better (probably a little bit less chromatic aberration) but the Tal 100 has a smaller focal length that helps to get an larger angle of view. So both have their advantages.
After short time I was told that the ED refractors are much better although I haven't asked for that comparison
The name "planet killer" is a little bit weird but OK.
Clear sky,
Roland

Quote:

Personally I had now the RS100 Tal, last model, and the 120ED SW in hands, owned the vixen 100F10.
Lastly on saturn the 120ED and the tal 100 exhibited fine results but with actually no significant different results about the accessible features.
I have to compare this also on venus where the 100RS shows already fine banding structure on the atmosphere.
I donot agree with forumers here about the fact that 100mm aperture is confidential or too small.
This is with these kind of apertures that visual observers may train their vision with acurate optics in order to go deeper and deeper on a planet image.
I donot know what is this "planet killer" 100F11 but surely not outperforming what I tested already.
Stanislas-Jean




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stanislas-jean
Carpal Tunnel


Reged: 10/22/08

Re: "Planet Killer" new [Re: Niklo]
      #5944432 - 06/28/13 09:17 AM

From my comparisons with the said scopes, the ED brings in fact nothing more consistent about the acquisition of data, but with a more pleasant view only.
The 100RS has already a confidential CA level that can be annealed by the use of the MV Lumicon filter (that cut the violet halo under 410-415nm).
Now the ED (chineese) should do better that is not effectively and there are reasons for that are subtil.
It would be interresting to see the Arcturus star for example at high power in each case and to study their diffraction patterns.
The Tal involves a pattern very clean (circular airy disk with say max 2 rings appearing and some other so faint despicted on a light violet halo, discret), the ED involves a strange pattern consisting in an airy disk circular surounded by a first ring not strongly lighted and others, a dozen of distinct rings having a light degradation in intensity low. The rocnchi pattern has black lines straight (grid of 10 lp/mm) with no appearing curvatures that mean faint readable spherical aberration 1st order, but the other orders? The ED at 300x shows a coloured halo around Arcturus.
This is the fifth ED that I had in hands with similar effect (100mm, 110 and 120mm). Consequence is that small contrasts of fine details are washed.
The achromats (100mm and 150mm) didn't exhibit this effect, but low contrasted fine details were present visually.
This is my observations about sothat when the quality is actually here at a high level a 100mm even achromat gives excellent results and enough for making acurate and useful results at the level of an almost perfect aperture.
At present with the experience of ED scopes, they disapointed me a lot.
If somebody expect a 100mm achromat he can go to the vixen 100mm achromat that is without surprise about the quality level which is extra-fine.
Stanislas-Jean


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GOLGO13
Carpal Tunnel


Reged: 11/05/05

Loc: St. Louis area
Re: "Planet Killer" new [Re: Pete-LH]
      #5944740 - 06/28/13 12:49 PM

Certainly this is a marketing ploy more than anything. It's not much longer than the Celestron 102mm F9.8 scopes. Now, those do very well on planets (had one back in the day), but I can't say they are planet killers. Quite frankly I'd say you would need at least one more inch in aperture to get into a more serious planetary killing scenario. A few more inches would really help there.

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PJ Anway
Double-Star Observer
*****

Reged: 06/04/03

Loc: North Coast
Re: "Planet Killer" new [Re: GOLGO13]
      #5945108 - 06/28/13 04:06 PM

IMO aperture size is only one factor in planetary observing. There are certainly other factors that can determine choice. For instance, because I live under very dark yet often turbulent skies, a 4" long-focus refractor makes a lot of sense for me for use on planets.
Those factors (in contrast to a large scope)are:
(1) the convenience of setting up a small refractor,
(2) the forgiveness of a long focal length when it comes to less-glass eyepieces,
(3) lower irradiation of the eye enhances contrast,
(4) less turbulent air to deal with.

Of course when it comes to faint "fuzzies" the light-grasp of a larger scope wins.


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Pete-LH
sage
*****

Reged: 03/25/09

Loc: Wilmington, DE
Re: "Planet Killer" new [Re: stanislas-jean]
      #5945242 - 06/28/13 05:30 PM

Stanislas-Jean,
Totally understand your "the acquisition of data" reference verses more expensive scope designs. There is a good article in a recent Astronomy League "Reflector" on how some young attendees to star parties/outreach gatherings may be scared away by the expense of some equipment. Personally when considering the "the acquisition of data" aspect, I get as almost all visual data with my simple 90mm Vixen 90M (probably can get for less than $300 used) as with any of my other telescopes. I have found that with 80 and 60mm scopes as well. Can't argue though that when conditions are good the views with my C9.25 or 5" refractor are just wonderful.


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