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Why would you want a 6 inch Achromat?

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#26 Gofr

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Posted 07 January 2018 - 11:15 AM

I was looking at the Starwave 152mm myself and seems excellent. I would love one, but new the run a cool $1200 CAD. I can get a new 6 inch F8 at $700 CAD new. Not sure I'd be willing to spend an extra $500 on it. Then ofc there's the used market.

#27 russell23

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Posted 07 January 2018 - 11:16 AM

I think a 6" achromat makes a lot of sense for someone that prefers refractors and also wants enough aperture for deep sky.  You can clean up the views of a 6" achromat significantly with a filter and you will have the sharp images a refractor provides at a significantly lower cost than a 6" APO. 


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#28 VNA

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Posted 07 January 2018 - 01:00 PM

A 6" achromat such as my CR6 is hard to beat for performance and particularly for its price.

Using a fringe filter helps a great deal and if not enough there is an aperture  reducer.

The CG5 mount is somewhat wobbly unfortunately.

With 2" eyepiece it gives really nice and sharp views. 

Could not spend 10 times for an APO because it does not give a 10 times better image! (not even close)


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#29 Crow Haven

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Posted 07 January 2018 - 01:28 PM

 

I have the Celestron Omni XLT 6" f/5 (and also the CR6 f/8 currently stored away) and love it for the wide-field low mag. views.  At 16 lbs.+whatever accessories you choose it's not a big deal to mount.  I prefer using it on my Twilight II alt/az mt. either alone with a counterweight on the other saddle or use another ota -- even a 6 to 7" Mak for planetary or other apo refractor at the same observing session.  Works for me! grin.gif  YMMV.

If you don't mind me asking, have you ever mounted or run the 6" f/8 on your Twilight II?  If so, how well does the mount perform on high power planetary viewing, and also on changing eyepieces from heavy to light?  I've often considered moving my 6" to a Twilight II and mounting an Orion 180 Mak-Cass on the other side for planetary viewing.

 

No, I haven't tried it on the Twilight II so I can't say if it works.  Because of its length I would think the Twilight II (I have the pier extension already on it) would benefit from the pier extension...but maybe sitting close to the ground would work even without it.  I just can't say, so I'm sorry this isn't helpful to you.  I do use the 180 Mak as well as other otas and it works well up to your ability to track manually at whatever high mag. you can.  For planetary sketching and longer study/higher mag. sessions I'll use a tracking mt. as it's more convenient.  While the Twilight II mt. by itself isn't super- light weight for grab-n-go it's still pretty easy, in my case, to carry it outside plop it down and then go get the scopes to put on it = a quick setup -- the 6" f/5 and the 180 Mak are fun partners of similar wts. allowing for casual sessions of whatever the seeing allows.  I start out on the wide-field views and try out the Mak later if conditions are good for it.  I also have smaller Maks and apos which can quickly be switched out on the Twilight II.


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#30 junomike

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Posted 07 January 2018 - 05:00 PM

Why?  Best bang for you buck on a "Yard Canon".  Also, there's a ton of DSO's that look real nice through it despite it's poor color correction.


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#31 ValeryD

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Posted 08 January 2018 - 12:35 AM

Could not spend 10 times for an APO because it does not give a 10 times better image! (not even close)


A 5x priced car is not necessary 5x faster and 5x more comfortable. But you takes this easily.
Why not take the same logic with achromats and apochromats?

Edited by ValeryD, 08 January 2018 - 12:36 AM.

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#32 Ziggy943

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Posted 08 January 2018 - 11:53 AM

In their long version they make an awesome telescope.

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#33 Peter Besenbruch

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Posted 08 January 2018 - 12:55 PM

In their long version they make an awesome telescope.

Longest 6", f8 I've ever seen. ;)


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#34 Dave Ponder

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Posted 08 January 2018 - 01:19 PM

Thanks guys for the comments, much appreciated.  I just ordered the ES AR152 version and an extra 12lb counterweight for the AVX.  Will let you know how it goes!

Clear Skies!

Dave


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#35 gustavo_sanchez

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Posted 10 January 2018 - 03:09 PM

 

I have the Celestron Omni XLT 6" f/5 (and also the CR6 f/8 currently stored away) and love it for the wide-field low mag. views.  At 16 lbs.+whatever accessories you choose it's not a big deal to mount.  I prefer using it on my Twilight II alt/az mt. either alone with a counterweight on the other saddle or use another ota -- even a 6 to 7" Mak for planetary or other apo refractor at the same observing session.  Works for me! grin.gif  YMMV.

If you don't mind me asking, have you ever mounted or run the 6" f/8 on your Twilight II?  If so, how well does the mount perform on high power planetary viewing, and also on changing eyepieces from heavy to light?  I've often considered moving my 6" to a Twilight II and mounting an Orion 180 Mak-Cass on the other side for planetary viewing.

 

I do have my AR152 mounted in a Twilight II and use it occasionally for lunar viewing. Mount is stable enough for it when I use a CW on the other saddle. At least I didn't notice major vibrations while observing, just when I touch the focuser but they die off rather quickly, less than two seconds.



#36 tomwall

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Posted 10 January 2018 - 03:35 PM

Hi Dave,

How are the views?

The views are very good.

 

However... The set up and tear down for the AVX mount takes some time. The 152 doesn't get to see as much sky is time as it deserves because it is just SO much faster to use my c102mm (f9.8) or my c8/SE. It's a trade off. One of those T-mount adaptors might be fun and simple.



#37 lulz

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Posted 11 January 2018 - 05:25 AM

I'd want one for DSOs and/or building a solar scope
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#38 tomwall

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Posted 11 January 2018 - 09:32 AM

Just for background, I built a Badar solar filter for my 152 at my local club. It works quite well. However, I get as good an image from my c102 (f9.8) and ETX90 (f13.5) when I use the same filter. Thanks to my wife for holding the filter so I didn't go blind. :-)


Edited by tomwall, 11 January 2018 - 10:16 AM.

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#39 rogeriomagellan

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Posted 11 January 2018 - 11:50 AM

Hi, everyone.

 

It is hard to believe that the ES AR152 is not among the best achromats available out there. However, there are two other options that appeal to me as well. The TS 6" f/5.9 with a fine 2.5" rack-and-pinion focuser and the red Starwave with the same specifications from Altairastro are two of them:

 

https://www.teleskop...-Objective.html

 

https://www.altairas...rd-focuser.html

 

Bresser has a 6" achromat but it is f/5. However, it is not a simple doublet. It is a 4-lens telescope. For more info, click on the link below:

 

https://www.teleskop...60-mm--OTA.html

 

For those interested in a 6" f/7.9 achromatic refractor, the Bresser Messier below may fit the bill:

 

https://www.teleskop...00-mm--OTA.html

 

I hope that my comments were of some help.

 

Clear skies.


Edited by rogeriomagellan, 11 January 2018 - 11:52 AM.


#40 Mikefp

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Posted 12 January 2018 - 10:25 AM

Thumbs up on the Jaegers 6" f15 yard canon. I do enjoy when I use it for planetary viewing. I set up at public viewing and enjoy peoples comments about the scope.

DSC01304.JPG
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#41 daquad

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Posted 12 January 2018 - 11:20 AM

Hi, everyone.

 

It is hard to believe that the ES AR152 is not among the best achromats available out there. However, there are two other options that appeal to me as well. The TS 6" f/5.9 with a fine 2.5" rack-and-pinion focuser and the red Starwave with the same specifications from Altairastro are two of them:

 

https://www.teleskop...-Objective.html

 

https://www.altairas...rd-focuser.html

 

Bresser has a 6" achromat but it is f/5. However, it is not a simple doublet. It is a 4-lens telescope. For more info, click on the link below:

 

https://www.teleskop...60-mm--OTA.html

 

For those interested in a 6" f/7.9 achromatic refractor, the Bresser Messier below may fit the bill:

 

https://www.teleskop...00-mm--OTA.html

 

I hope that my comments were of some help.

 

Clear skies.

Looks like the Starwave and TS do have the 2.5" R&P focusers, an excellent upgrade from the Crayford, IMO and both look like Kunming beauties.  


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#42 Phillip Creed

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Posted 12 January 2018 - 03:40 PM

I've heard good things about the 152 Starwave and other 6" f/5.9 Kunmings, but I'm still quite skeptical about its performance due to being screaming-fast for an achro.  But I've never looked through one.

One thing I'd like to see (translation--it'll never happen) is a 6" f/6 ED doublet.  "But...but...it'll have false color!!"  Duly noted.  Don't care.  I'm a visual observer, and I found a non-SDF Genesis (more or less same CA as a 4" f/12 FH doublet) more than good enough.  Even a 6" f/6 FPL-51 would have way, WAY better color correction than any 6" f/6-f/8 FH doublet out there.

But I can't fathom any commercial firm making one; imaging nowadays is the acid test.

Clear Skies,

Phil


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#43 Gofr

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Posted 12 January 2018 - 05:42 PM

I've heard good things about the 152 Starwave and other 6" f/5.9 Kunmings, but I'm still quite skeptical about its performance due to being screaming-fast for an achro.  But I've never looked through one.

One thing I'd like to see (translation--it'll never happen) is a 6" f/6 ED doublet.  "But...but...it'll have false color!!"  Duly noted.  Don't care.  I'm a visual observer, and I found a non-SDF Genesis (more or less same CA as a 4" f/12 FH doublet) more than good enough.  Even a 6" f/6 FPL-51 would have way, WAY better color correction than any 6" f/6-f/8 FH doublet out there.

But I can't fathom any commercial firm making one; imaging nowadays is the acid test.

Clear Skies,

Phil

Well, they do make 'em at F8, but that seems to be the best we'll get.



#44 Planethunter80

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Posted 12 January 2018 - 07:44 PM

In their long version they make an awesome telescope.

That is utterly beautiful. Thanks for sharing that incredible image  bow.gif 



#45 stevew

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Posted 13 January 2018 - 02:51 PM

As long as the lens has a good figure and is well corrected for c/a and s/a, a well made six inch achromat can be a lifetime scope.

 

Steve

 

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#46 John O'Hara

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Posted 13 January 2018 - 05:55 PM

I've heard good things about the 152 Starwave and other 6" f/5.9 Kunmings, but I'm still quite skeptical about its performance due to being screaming-fast for an achro.  But I've never looked through one.

One thing I'd like to see (translation--it'll never happen) is a 6" f/6 ED doublet.  "But...but...it'll have false color!!"  Duly noted.  Don't care.  I'm a visual observer, and I found a non-SDF Genesis (more or less same CA as a 4" f/12 FH doublet) more than good enough.  Even a 6" f/6 FPL-51 would have way, WAY better color correction than any 6" f/6-f/8 FH doublet out there.

But I can't fathom any commercial firm making one; imaging nowadays is the acid test.

Clear Skies,

Phil

I'd think that a 6" f/6 ED doublet would be at least as well corrected for chroma as my 1986 6" f/8 Astro-Physics refractor, which was a "standard" glass triplet corrected for visual use.  That scope is a killer visual instrument, even though the chroma correction is not as good as today's triplets with exotic glass.


Edited by John O'Hara, 13 January 2018 - 05:56 PM.

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#47 CHASLX200

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Posted 13 January 2018 - 06:23 PM

I know the older CG5 is way too small for a 6" F/8.  I would say a G11 would be much better.



#48 Planethunter80

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Posted 13 January 2018 - 06:26 PM

Thumbs up on the Jaegers 6" f15 yard canon. I do enjoy when I use it for planetary viewing. I set up at public viewing and enjoy peoples comments about the scope.

attachicon.gifDSC01304.JPG

There is just something about long focal length refractors that make me smile. If I had the space and the funds a scope like this would be my ultimate instrument of choice.

Thanks for the outstanding image. waytogo.gif 


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#49 Planethunter80

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Posted 13 January 2018 - 06:28 PM

As long as the lens has a good figure and is well corrected for c/a and s/a, a well made six inch achromat can be a lifetime scope.

 

Steve

 

Steve is that a Losmandy mount your long and luscious refractor is riding on?



#50 Steve Cox

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Posted 13 January 2018 - 06:33 PM

I know the older CG5 is way too small for a 6" F/8.  I would say a G11 would be much better.

If you're talking the older mounts prior to the CG-5A with the upgraded 2" stainless steel legs and upgraded ball bearing axes I agree.  But the CG-5A and ASGT (same mount just different electronics) handle the 6" f/8 just fine for visual, especially if you add the Orion 16" pier extension.




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