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Old 11-03-2017, 03:15 PM
Hazza777 (Harry)
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ED Doublet vs WO Triplet

Hey,
Been a long time lurker of these forums over the years and the wealth of knowledge and experience here is great! I've been researching equipment for beginning some more serious Astrophotography with my Nikon D5100 and a little visual viewing for months now and information from this and other forums has been incredibly helpful.

I've finally settled on a mount (SW azeq6) and thought I had narrowed down the scope to one of the 'cheap' but highly recommended ED80 doublet APOs (likely SW f7.5 2"Crayford focuser MHC coatings) and banking the coin saved for a nice EP/flattener set etc or to put towards a larger scope somewhere down the line (after all that's the plan for going so far overboard with the mount). But a couple of nights ago I discovered the Williams Optics A-F81GT-VP20A-AP f5.9 triplet (2" R&P focuser and STM coatings) and thought it looked amazing (for the prices listed ~1900 with Flat6A-81 at F4.7). Is this a worthwhile investment of an extra ~850 considering I plan on keeping this scope likely for my lifetime or should I turn back to my original game plan? It's quality does seem better (although maybe just in my head) I haven't been able to find any back to back comparisons between it and the regular doublets.

Any other suggestions are welcome, thanks for your consideration.

Last edited by Hazza777; 11-03-2017 at 03:33 PM.
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Old 11-03-2017, 04:05 PM
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Camelopardalis (Dunk)
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Welcome to Ice in Space Harry!

For visual, I'd say don't spend the extra money.

But for imaging, a triplet will have better colour correction, that will be more noticeable once you start doing long exposures.

Have you thought about what focal length scope suits your targets best?
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Old 11-03-2017, 04:47 PM
SkyWatch (Dean)
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Will the SW be that much cheaper when you throw in the flattener?

BTW, I noticed a review here: http://www.cloudynights.com/topic/38...d-80mm-f75-ed/ that mentions the author's previous Williams scope...

Personally I think if you are going for a "lifetime" scope then you should get the best you can afford. Williams scopes are very well made, and their service is very good (I have dealt direct with them in the past and they bent over backwards to help). This particular one will give you a wider field than the SW and as a triplet it will probably be better colour corrected and therefore give sharper images for astro photography.

All the best,

Dean
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Old 11-03-2017, 04:49 PM
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dannat (Daniel)
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id wait & try & find one secondhand, a triplet is what most use for photography

also check the 71Fl Borg or the 89ED Borg from tan14.com
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Old 11-03-2017, 05:03 PM
Hazza777 (Harry)
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Quote:
Originally Posted by Camelopardalis View Post
For visual, I'd say don't spend the extra money.

Have you thought about what focal length scope suits your targets best?
Cheers Dunk,

Visual won't be the top priority at first but I do plan on keeping this scope as a primary visual or guide scope after I've out grown it for imaging.

I was looking at the 600mm (618mm for the WO) FL APO's because I figured wide angle shots are a good place to start for imagaing with plenty of targets then I can move onto a longer SCT or MAK in a few years once I've thoroughly exhausted all the bright DSO's and honed processing skills.
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Old 11-03-2017, 07:09 PM
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I'd also suggest the SW Esprit range for consideration. Built well and work well, although a little more than the WO.

Just remember that the GT81 with reducer/flattener as mentioned in your first post will bring the focal length down to about 380mm. If you wanted something around that focal length, I'd suggest the WO Star71-II. Small, light and will cope with a full frame DSLR.
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Old 12-03-2017, 01:33 AM
Hazza777 (Harry)
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Keeping an eye out Daniel, got some holiday time coming up so hopefully something will show up soon!

Quote:
Originally Posted by SkyWatch View Post
Will the SW be that much cheaper when you throw in the flattener?

BTW, I noticed a review here: http://www.cloudynights.com/topic/38...d-80mm-f75-ed/ that mentions the author's previous Williams scope...



Thanks for the input Dean! Hadn't come across that review but it was a good read.

A FF/FR for the SW is only ~$275 so it still comes out much cheaper and the SW also comes with 2" dialectric diagonal w 1.25" adapter, 2"LET 28mm EP, 8x50 finder scope.

The WO 81 has similar options available for 1-200 more, which is getting the to the very limits of my budget unless one of the other vendors I've contacted for prices on this scope get back to me under the current benchmark.


Quote:
Originally Posted by Camelopardalis View Post

Just remember that the GT81 with reducer/flattener as mentioned in your first post will bring the focal length down to about 380mm. If you wanted something around that focal length, I'd suggest the WO Star71-II. Small, light and will cope with a full frame DSLR.

I hadn't even considered the ramifications a FR would have on Focal Length and Image Circle... haha that sent me down a very deep rabbit hole I think I'll need to take some time to get a full working command of.

Gosh the Star71-II looks wonderful, 2.5" focuser, much faster and the photos on astro bin.... WOW! (Though all taken with much better equipment than my humble nikon). but even more pricey than the 81 without any EP and I likely wont be upgrading from my APS-C D5100 to a full frame or CCD for a long time by which hopefully I'll be able to afford a decent reflector. Not sure that extra speed/shorter FL would be worth the money for a beginner but now seriously considering downgrading the AZEQ6 to an AZEQ5 ($400-$500 difference for the tripod/pier models) to accommodate that scope. Luckily its light but I still feel if I couple it with an 8" SCT or MAK as a guide scope later on it will overload the AZEQ5.... Will have to contact a few sellers and see what the best offer for a Star71-II is.

Thanks everyone for the welcome and the input!
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Old 12-03-2017, 03:45 AM
Hazza777 (Harry)
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Not sure how I missed it but just stumbled across this similar and very helpful thread.
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Old 12-03-2017, 07:00 AM
dimithri86 (Dimithri)
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Hey,

Also remember if you are planning on doing narrowband imaging...with a mono camera and filters, then colour correction isnt important.

I have an APO triplet and DSLR. But if I could do it again I would go with a 80ED and a imaging camera with filter set.
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