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AT 0.8X reducer/flattener for AT115 (is this correct ?)

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4 replies to this topic

#1 17.5Dob

17.5Dob

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Posted 13 February 2019 - 10:34 PM

I'm glad I didn't toss away the little box that came inside my FR/FF.

I've only had a chance to use it once, and wondered why mine didn't look the photos.........

It did a "good job" not perfect, but good across  ~85% of the field. Again tonight I was wondering why mine only read "AT 0.8 Reducer/Flattener " on the barrel. I looked at the closeup photos at Astronomic's site and saw a collar that was missing on mine that read "for 115 APO". I went through the box again and noticed something rattling in the little box I thought was just "packing filler".

Inside was a spacer ring with the "For 115 APO" label........I "assume" that I need to thread it on the end of the barrel to get the correct spacing for the 115 as shown in Astronomic's photo.



59a51149-465e-496f-a29b-3d8ec488743a.png


Edited by 17.5Dob, 14 February 2019 - 09:42 PM.


#2 17.5Dob

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Posted 14 February 2019 - 09:41 PM

Is this how AT makes their "dedicated" flatteners ? One body and different width rings for the various radius of curvatures ?



#3 John Miele

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Posted Yesterday, 01:34 PM

wow this has me stumped...if you thread it on the end of the barrel where the picture shows it, how does that change anything about the way the reducer works? Or maybe I'm missing something. I'd like to know as I also have an AT115EDT and plan to buy one of these myself...John



#4 Astrola72

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Posted Yesterday, 03:42 PM

Yes, that's where it goes (only place it will go). I don't know if this same FR is used for other scopes. This piece does seem to be just a spacer, but a very thin one (much thinner than it looks in the pic when you check the thread depth). I haven't yet figured out how to fit in an OAG and FW and the 17mm backfocus of my 383L+, and still keep to 55mm total backfocus, so I haven't used mine yet. I've got some very thin shims on order from Agena.

 

Joe



#5 17.5Dob

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Posted Today, 01:44 AM

This is a full frame photo (uncropped) without the the little AT115 spacer ring. The field curvature is noticeable but "fairly" slight.

 

46076122665_9fcf9d1614_h.jpg




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