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Flattener for Explore Scientific 152CF scope?

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#1 Peter in Reno

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Posted 19 July 2013 - 11:12 PM

Anyone that owns Explore Scientific 152 Carbon Fiber Apo scope use flattener for imaging? Since this scope has not so small or fast focal ratio of F/8, is flattener necessary for imaging with large format CCDs like Kodak KAI-11002 CCD or equivalent?

I have seen few wonderful images taken with this scope and flatteners were not mentioned. It would be nice if flattener is not necessary, then I wouldn't have to worry about short back focus which can be typically at 100mm or less.

If flattener is recommended for imaging with this scope, what brand and model would you suggest?

Thanks,
Peter

#2 dsnope

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Posted 20 July 2013 - 01:20 AM

Perhaps the flattener for the APM 152/1200?

#3 orion69

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Posted 20 July 2013 - 02:09 AM

I don't think there are refractors that don't need FF for AP (except for Petzvals).
I'm waiting for TS 150 APO which I ordered with Riccardi 0.75x FF/FR, I hope it will be a good match.
Also, while I have no experience with Explore Scientific 152 Carbon Fiber Apo (and don't question its quality), I should mention that generally speaking, CF tube for refractors is not recommended for AP.

#4 vi100

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Posted 20 July 2013 - 05:22 AM

Hello Peter,

I own a ES ED127CF and I'm very satisfied with it.

I use it for imaging and, of couse, I use a Flattener. In this case, I use the TS Flat2 that give me a very nice flat field on my QHY9 CCD chip.

You can read (in spanish) this quick review. I wish this can help you:

http://buscandocomet...-flattener-p...

#5 vpcirc

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Posted 20 July 2013 - 06:39 AM

Peter I think Stellarvue's will work. Check with Vic Maris. He builds refractors there and can tell you

#6 Peter in Reno

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Posted 20 July 2013 - 06:53 PM

Thanks for your responses. I search for every possible flatteners for refractors and their back focus seem quite short. I like Stellarvue flatteners due to their large size for large format CCD cameras but their back focus is about 55mm which is quite short. I prefer to autoguide with OAG/ONAG instead of using guide scopes and having OAG can add some back focus. QSI seems to be the best camera for this because it has built-in OAG and reasonably short back focus of around 50mm.

Thanks for your inputs.

Peter

#7 dsnope

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Posted 20 July 2013 - 08:29 PM

This one has 70.4 mm backfocus:
http://www.apm-teles...ducer-/-Corr...

#8 Peter in Reno

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Posted 21 July 2013 - 06:43 PM

I was exchanging PM messages with a fellow CN'er who also owns ES152CF. He use this Flattener with great success. The back focus varies between 91mm and 101mm depending on focal ratio of refractors. They have an adapter you can purchase to thread the flattener directly to the 3" Feathertouch focuser which ES152CF uses. The flattener claims to illuminate a full-size sensors.

Peter

#9 vi100

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Posted 22 July 2013 - 12:38 AM

I was exchanging PM messages with a fellow CN'er who also owns ES152CF. He use this Flattener with great success. The back focus varies between 91mm and 101mm depending on focal ratio of refractors. They have an adapter you can purchase to thread the flattener directly to the 3" Feathertouch focuser which ES152CF uses. The flattener claims to illuminate a full-size sensors.

Peter


This is the big bross of my TSFlat2 that works fine as I said a few post ago. ;)

#10 Mike Wiles

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Posted 22 July 2013 - 01:15 PM

I was exchanging PM messages with a fellow CN'er who also owns ES152CF. He use this Flattener with great success. The back focus varies between 91mm and 101mm depending on focal ratio of refractors. They have an adapter you can purchase to thread the flattener directly to the 3" Feathertouch focuser which ES152CF uses. The flattener claims to illuminate a full-size sensors.

Peter


Here is my complete imaging train:

Explore Scientific ED152CF f/8 Triplet
Teleskop Service Adapter to attach flattener to a 3" Feathertouch focuser
Teleskop Service 2.5" Field Flattener (91 mm backfocus)
Precise Parts custom adapter to attach flattener to SBIG off axis guider (35mm in length)
ST-L threaded faceplate for the OAG-8300 to maximize the clear aperture...this was ordered directly from SBIG.
SBIG OAG-8300 off axis guider.
SBIG FW8-8300 8 position filter wheel
SBIG ST-8300m CCD camera (no longer manufactured).

This setup provides a fully threaded/bolted imaging train from camera to objetive. There is 91mm of backfocus between the flattener and the CCD chip. I've been very happy with the results that I've gotten so far. When I switched to this flattener from the Hotech SCA flattener, I saw a noticeable difference in the end result. I attribute this to the threaded/bolted connections of the current image train. My camera/filter/oag setup is just shy of 5 pounds...too much weight for the compression ring connection of the old flattener.

Here's a few links to full resolution images shot with this combo. Star profiles in all four corners are as good as I expected. Granted, it's not a huge chip by any means....but I've been happy with the results.

M16 Hubble Palette (full resolution)

M101 LRGB w/H-Alpha (full resolution)

IC443 HaRGB (full resolution)

I can scare up and post original FITS files for any of these images if there's interest in seeing the raw data for your own analysis. I couldn't be happier with the results that I've been getting so far with this scope and setup. Any complaints that I have are attributed directly to some image processing skills that I still lack....


Mike

#11 Peter in Reno

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Posted 22 July 2013 - 02:03 PM

Mike,

Thank very much for your time writing your report. Your images are excellent and show very nice stars.

Peter






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