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Other 400C users


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#1 nakbrooks

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Posted 07 September 2016 - 08:35 AM

Is anyone else on the forum operating the 400mm Cassegrain (or 500C/600C - they are much the same) with the 4" corrector?

I have a small problem I would like some help with if possible.

Thanks.
Nigel Brooks
Stratis Observatory, Hautes Pyrénées, France.
http://www.facebook.com/stratisobservatory

#2 lukepower

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Posted 07 September 2016 - 10:37 AM

Nigel,

well, I have my 20" which also uses the 4" reducer/corrector (I have the corrector here as a spare part but never used it). The tube wasn't made by ASA; though


Lukas Demetz
------------
www.skygemsobservatories.com
Astro Dolomites Observatory, Skygems Network
Santa Cristina Valgardena, Italy
20" Cassegrain-Newton on ASA DDM85XL


#3 nakbrooks

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Posted 07 September 2016 - 11:10 AM

Thanks Luke. I'm trying to find someone with the same OTA configuration as me (400C, ASA rotator, 4" corrector) so I can work through some back-focus problems.

I will post more details a bit later.
Nigel Brooks
Stratis Observatory, Hautes Pyrénées, France.
http://www.facebook.com/stratisobservatory

#4 lukepower

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Posted 07 September 2016 - 12:38 PM

Back focus was a pain in the ass for me, a bit due to the tight requirements of the ASA correctors, and even more due to the mechanical construction of my OTA combined with the optics (which were, surprise, a little below the projected f/3 and thus the backfocus was lower than expected).


Lukas Demetz
------------
www.skygemsobservatories.com
Astro Dolomites Observatory, Skygems Network
Santa Cristina Valgardena, Italy
20" Cassegrain-Newton on ASA DDM85XL


#5 nakbrooks

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Posted 07 September 2016 - 02:28 PM

I've moved this to the Correctors section as it is more relevant there.


Nigel Brooks
Stratis Observatory, Hautes Pyrénées, France.
http://www.facebook.com/stratisobservatory




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