Esprit 100 & Starizona 0.65 Reducer Sky-Watcher Esprit 100ED · Christian Schulbert · ... · 3 · 335 · 0

Chris_16 0.00
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Hi,
I got a Starizona 0.65 Reducer for my 100 ED. The nominal backfocus distance should be 58 mm. I tested a lot, but I got always elongated stars in the corners, which indicates, the camera (APS-C-IMX571) is too close. I am now at 59.5 mm and still get elongated stars. Has anyone found a working distance with this combo?

Clear skies,
Chris
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Andreas_Kenda 0.00
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Hi Chris,

I am using the same combo and started by accident at 60mm backfocus. I did not like that BFL as I got tangentially deformed stars. I am now at 58.5-59mm which is the nominal 58mm + 0.7mm to account for the 2mm thick filter. I think it is working better in terms of getting small stars round. However, bright stars produce violent bursts: https://www.astrobin.com/full/fq0wcd/0/
Do you see the same effect?

CS, Andy
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janvalphotography 1.81
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Following this as I have been keen to add a smaller FL option, but a working reducer could also be an option. I've always been a bit skeptical towards the Starizona though as I haven't really seen any compelling results or a general consensus considering backfocus.
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Drothgeb 0.00
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Jan Erik V:
Following this as I have been keen to add a smaller FL option, but a working reducer could also be an option. I've always been a bit skeptical I use towards the Starizona though as I haven't really seen any compelling results or a general consensus considering backfocus.

I use the 3” Explore Scientific .7x. It works really well on multiple scopes
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