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Old 12-02-2019, 02:34 PM
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Ed80 ff/fr

Hi everyone,


I like to get a FF/FR for my ED80 F7.5 refractor with Canon's 1100D.


Google search come up with Orion's 0.8x.. Bintel has this and cheaper.

But the better one is SW 0.85X .... can't find it in AU.


https://optcorp.com/products/sky-wat...ro-ed80-s20200


The SW 0.85 screw directly to the focuser.

I want to use this with the Celestron OAG ... have lots of adapter, hope one of them will match the SW thread.


My question is, would this set-up reach focus? OTA>FOCUSER>OAG>0.85>T>1100D


Thanks for any help.
Mick
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Old 12-02-2019, 03:25 PM
JA
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At the risk of a curve ball....

That 0.8-0.85x reducer is about $US 249 = $AU 351.

For around two times that price or below, say $600 to $700 (if you're a good wheeler-dealer) you could have a used Canon 6D fullframe camera, which would yield a far cleaner image and give you a much wider field of view. It would be the equivalent of 1/1.6 ~= 0.625x reducer AND you will not have added any additional optics in to the optical path, which can degrade contrast and add abberations.

Best
JA
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Old 12-02-2019, 03:34 PM
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Hi JA,


Using a full-frame 6D without a field-flattener... well, it's not pretty.
The 1100D I use is full-spectrum and cooled, modified by me. Not going to do that to my 6D


But to the point, a simple doublet has a field curvature and that is need to be corrected even for a APS-C size sensor... let alone a 6D full frame.
So the FF/FR has dual function. An Astrograph corrected for full-frame is beyond my $$$



Cheers,
Mick
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Old 12-02-2019, 03:44 PM
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^ Ok - Rock on Mick.

Best
JA
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Old 12-02-2019, 04:51 PM
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that_guy (Tony)
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is this what you're looking for? http://www.astroanarchy.com.au/Acces...ucer_ED80.html
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Old 12-02-2019, 05:04 PM
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Yes, thnx Tony
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Old 14-02-2019, 12:36 PM
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Thanks again Tony for the tip, and to Astro Pete.



Placed an order yesterday, got it today in Adelaide.
Excellent costumer service


Now, I need clear sky to try and see how much in-focus need.

Hope enough left for the big Celestron OAG.


Cheers,
Mick
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Old 17-02-2019, 08:16 PM
kon1966 (Kon)
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Fr

Hi guys,
i just use a 6.3 reducer with 1100d.
Kon
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Old 21-02-2019, 10:44 AM
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Hello everyone,


A quick test of the SW FF/FR 0.85x
It works, no distortion in the APS-C DSLR corner. Hope the uploaded pic will show the difference.


I needed to get a 56M TO 48M adapter to attache to the OAG, and have to use the thin OAG to get to focus with on the 80ED. My preferred OAG is the more solid Celestron... have to work on that. Shorten the OTA or buy a 2" helical focuser and make an adapter.


Mick
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