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Old 15-11-2021, 10:52 AM
bluesilver (Peter)
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bluesilver is offline
Join Date: Jul 2018
Location: Australia, Tasmania
Posts: 319
Thanks for the replies and advice, appreciated.
Yes, i have measured up everything and the total amount of spacers come to
So i might be actually 2mm too long in my case as you mentioned, 78.5mm is the number i would be looking for then.

Will it make any noticeable difference being 2mm too long?
I have tried doing a bit of a search to find out what happens if you are too long or too short from the optimal back focus, and all i get is that you won't reach optimal back focus.

So not sure what actually happens there, will the stars be out of focus or something? as you can adjust focus via the focuser itself, a tad confusing there.

If i am the fore 2mm too long, i think the best option would be to shorten the spacers made by ZWO as they appear to be a common size, so either go for a M42-M48 14.5mm extender or a M42-M42 19mm extender, just finding then at this size could be a challenge though.
The Flattener has a 68mm thread, so finding something to fit that would be much more of a challenge.
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