#1  
Old 03-07-2015, 01:45 PM
HarryD (Greg)
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William Optics AFR-IV problem

Hi to you all.

I have a Williams Optics FLT 132 and a WO AFR-IV adjustable flattener reducer to which I have attached my QSI 683wsg. The focuser is a FeatherTouch FTF3545B.
So far so good......... however. Is there always a however with astrophotography? Never mind.
Nice scope, camera and focuser but I am not sure about the AFR-IV.

So, a question for anyone with the WO AFR-IV adjustable flattener reducer and an FLT 132.
Try as I might I still have coma at the edges of my QSI 683with the AFR-IV. I had a spacer (21mm approx) made by Precise Parts and focus is no problem. Stars in the centre are nice and round as one would expect. I get my best results (still have coma) when the AFR-IV is adjusted to the 66 mark and no more room to adjust. Should be at 72 or so according to WO.
Anyone out there had similar problems or indeed had success?

As a general question, what is the best way to attach the camera, reducer etc to the focuser? I am placing it into the focuser just like an eyepiece and tightening the two screws on the focuser at this time. It is very tight and doesn't flop around but is it all aligned etc.

Is there a better way?

Thanks in advance, Greg.
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  #2  
Old 04-07-2015, 09:35 AM
cfranks (Charles)
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Hi Greg,
If I get a clear sky soon, I might be able to help. I have the exact same setup except with a home made spacer. I managed to get the FLT132 collimated a couple of months ago, indoors, but have been clouded out since. It certainly sounds like you have Field Curvature and if that is symmetrical around the image you should (?) be able to adjust the FF. Do you have any analysis software to show the curvature? I use CCDInspector but I'm sure there are others.
Cheers
Charles
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Old 04-07-2015, 11:57 AM
cfranks (Charles)
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Another thought. The spacer I made is 27 mm long but that is bolted directly to the WSG plate. Yours sounds correct if you are screwing it to a T-Mount adapter. Is that the case?
Charles
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Old 04-07-2015, 04:09 PM
HarryD (Greg)
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Hi Charles

Thanks for your response.

Yep, attached to the T mount.

I don't have any software to measure field curvature. Maybe I should find something I can use.

I do have some different spacers so I will give them a try and see what happens.

It's all a learning experience, along with plate solving, meridian flips etc and that's just getting the images.

Cheers
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  #5  
Old 04-07-2015, 06:30 PM
cfranks (Charles)
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Hi Greg,
If you have a DropBox account or similar, you can upload an original image and I could check it for curvature etc. I'm not sure when I am going to get a clear sky again, so I'm looking forward to you getting a good result, then you can tell me how you did it!
Cheers
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  #6  
Old 14-07-2015, 08:04 PM
HarryD (Greg)
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Hi to you all.

Thank you for your input.

Problem solved. I spent $46 on a set of Orion T thread spacers. The 12.5mm spacer works a treat. Even round stars on the OAG guide camera.

Go figure.

Cheers

Greg
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  #7  
Old 14-07-2015, 09:09 PM
cfranks (Charles)
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Thanks for letting me know. That is your Flattener setting now? Do you get the #72 as WO suggest?

Charles
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  #8  
Old 15-07-2015, 02:06 PM
HarryD (Greg)
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Hi Charles

It's about one third of the distance between 66 and 76 on the WO flattener.
It's all a bit hit and miss. But with some playing around it all works.

Re the other "problem". I've ordered a new end cap from Starlight so I can screw the WO flattener on to my focuser. Good thing I have 4.5" of focuser travel as the new end cap has a much lower profile than the one I have.

Cheers
Greg
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  #9  
Old 23-07-2015, 09:16 AM
cfranks (Charles)
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Hi Greg,
One more question. Are you adding the Orion spacer to you Precise Parts spacer or using it instead of the PP?
Charles

Last edited by cfranks; 23-07-2015 at 09:17 AM. Reason: Spelling
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  #10  
Old 24-07-2015, 01:37 PM
HarryD (Greg)
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Instead of the PP spacer.
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