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Old 26-05-2022, 01:32 PM
JA
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Join Date: Oct 2016
Location: Melbourne, Australia
Posts: 2,976
Quote:
Originally Posted by bojan View Post
With the help of Astrometry.net, I calculated the actual focal reduction (standard SC-T2 camera adapter, backfocus 105~114 mm ) to be 0.589 (F/5.9).
So - next attempt will be with 85 mm backfocus.
Hi Bojan,

Also that reduction ratio of 0.589 you determined is very consistent with the ratio I would expect from the reported image circle diameter of the Celestron Reducer ( assuming it to be the same/similar to your Meade reducer). i.e: As per my previous post quoting a "24mm fully corrected image circle" with the Reducer versus presumably (Celestron don't say) a Full Frame Image Circle of the native C11 Telescope making the reduction ratio something like Full Frame (42 to 42.3mm) down to the 24mm stated or ....

24/42 ~= 0.57 (Close enough for Government Work )

Best
JA
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