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OAG in optical train for Refractor

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#1 Tristarcapt

Tristarcapt

    Sputnik

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Posted 11 February 2019 - 08:01 AM

Beginning to transition to OAG. Where in the imaging train should the OAG go? Specifically, should it come before or after my field flattener? Intuitively I’d think after. Since the OAG is probably picking up stars from the edges of the FOV. And, the closer the OAG is to the imaging camera the closer the guide camera can be to the OAG to achieve focus.

Am I on the right track there or way off base??

Scott

#2 RMannix57

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Posted 11 February 2019 - 08:17 AM

FF/OAG/Filter wheel/camera

Spacers as needed between FF/OAG to get correct FF-> camera spacing



#3 Tristarcapt

Tristarcapt

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Posted 11 February 2019 - 08:21 AM

Appreciate that, thank you!

Scott

#4 Astrola72

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Posted 11 February 2019 - 09:59 AM

The problem is that most FF and FF/FR put a tight limit on backfocus. Like 55-60mm. That has to include thickness of OAG, FW and backfocus of camera.

 

Joe



#5 Tristarcapt

Tristarcapt

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Posted 11 February 2019 - 10:55 PM

Hmmm, wonder if there are any field flattener’s that have a bit more generous back focus? I’ll be using a f/7 with a canon dslr. The camera body and t ring take up quite a bit already. Adding the OAG puts it over 60mm.


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