Williams 71 gt with rotator back focus William Optics Gran Turismo 71 / GT71 · Dan Kearl · ... · 5 · 310 · 0

AstroDan500 5.63
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I have my Williams 71 gt scope set up perfectly with back focus of 64mm..
I bought a Rotator because Williams is too cheap to have one and when I put it on it messed up all the focus,
I cannot even polar align now.
Has anyone had this problem? I took to off after screwing around for an hour and it works fine again.
What do I set the Flattener at with the added rotator to get the Scope in focus again.
I have an EAF attached.
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mgermani 5.38
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Where is the rotator attached - between the OTA & flattener, or between the flattener and camera? AFAIK, it should be between the OTA and the flattener, and then you don't need to touch the backspacing between the flattener and the camera.

If you're using an EAF, did you get it roughly in focus before starting your autofocus routine? If it can't identify any stars to use as a reference, the autofocus will fail.

Sorry if these are all things you've considered. CS!
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tarun2030 0.00
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·  1 like
I have a rotator attached to my GT71, it goes on to the scope before the Flattener and you dont have to touch the back focus !!
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jjpoole741 0.00
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Dan Kearl:
I have my Williams 71 gt scope set up perfectly with back focus of 64mm..
I bought a Rotator because Williams is too cheap to have one and when I put it on it messed up all the focus,
I cannot even polar align now.
Has anyone had this problem? I took to off after screwing around for an hour and it works fine again.
What do I set the Flattener at with the added rotator to get the Scope in focus again.
I have an EAF attached.

I have nine set to ~9.5mm on the flattener and it works fine. I think the guide says 9.1mm.
Like
tarun2030 0.00
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Dan Kearl:
I have my Williams 71 gt scope set up perfectly with back focus of 64mm..
I bought a Rotator because Williams is too cheap to have one and when I put it on it messed up all the focus,
I cannot even polar align now.
Has anyone had this problem? I took to off after screwing around for an hour and it works fine again.
What do I set the Flattener at with the added rotator to get the Scope in focus again.
I have an EAF attached.

I have nine set to ~9.5mm on the flattener and it works fine. I think the guide says 9.1mm.

Yes I have a similar setup !! Below is a image of the same !!
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Pariah 0.00
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If you have the 1.0x TS Flat it can cause issues if set up as rotator - flattener - backfocus- camera. The focuser extension is only 10mm with the TS flat so you wont get focus if you add a wo rotator

Which flattener are you using?
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