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Old 09-03-2021, 01:14 PM
evltoy (Wayne)
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Hi Paul,

If you have the STD 925 OTA, you might be in the same boat as me but not as bad. If this is the case you may want to look at this adjustable T-Adaptor to solve your issue instead of custom fab $$$.


For me this works well as I have many different size M42 spaces to make the correct backspace for my camera. Another bonus now is I will have clearance between my C8 with reducer and DSLR on the evolution mount.
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Old 09-03-2021, 01:24 PM
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The_bluester (Paul)
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I tend to go for custom bits once I have everything well sorted as I prefer to have as few individual parts as I can get away with in the image train, and I have bits from different manufacturers cobbled together too so the spacings often don't add up to simple ones in whole milliemeters.

I have a spare 5mm M42 spacer I can add to the train in front of the guider (In front of it to keep the guide camera parfocal with the main one) just to confirm that I flip the error from too close to too far. Assuming that then I will hopefully be able to fiddle in small increments with the spacers I have on hand to get it just right.

And after all that, I will probably change to a Newt next year anyway!
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Old 19-03-2021, 01:14 PM
evltoy (Wayne)
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Originally Posted by The_bluester View Post
Aha, wrong assumption on my part on what scope you were using.

As far as I know, if you are using the F6.3 reducer/corrector on an SCT, the warp speed versus fishbowl effect is reversed compared to a traditional refractor and reducer/flattener combination, so fishbowl equals too close, warp speed too far. I have to play a little with my C925 soon so I will be able to confirm that. It is very slightly a fishbowl effect and I was going to add 5mm to see if I can flip it to warp speed to confirm. Once I am sure of my spacing I was going to get a custom spacer done up.
ok.. bring this up again. Can some one confirm if the below is correct and would a spacer 5mm or under make a difference?

For my SCT
Fishbowl image means back focus is too close
warp speed image means back focus is too far

For my Refractor
Fishbowl image means back focus is too far
warp speed image means back focus is too close

by the way.. I just bought SharpCap pro. will give the PL a crack tonight on the SCT with NEQ6 mount

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