I own one of those, to use on a TMB 130 f/6 astrograph, but it is at a distant property, and I have yet to make or buy the adapter to mate it with my 3.5" FeatherTouch focuser. So I can't vouch for its quality, other than to note that its designer is well respected, and that it is designed to fill a 52 mm imaging circle. I've attached its nominal spot diagram out to 52 mm diameter. The BFL info is detailed (also attached as an Excel spreadsheet), but it is also a bit confusing, so you might want to double check your spacing. What scope are you pairing it with? That matters a lot in setting the BFL.
All the best,
Apo 130_780+075x reducer.pdf
Riccardi Reducer Info May 2014.xls
May I ask where is the xls coming from? Interesting enough there is a note on TEC140 I'm using and it says BF = 76.96mm.
As per AP documentation (RiccardiAdapation.pdf) and manual calculation the right distance to Atik383L is 73.5mm.
The background of this post is a nuuuumber of nights I spent to determine right BF for Riccardi attached to my TEC140 ( + two cameras ASI071 and Atik383 - both having same BF of 17.5mm).
So far no success for any distance between 69 and 76mm (where 76 distance image is already a disaster and this is probably the only solid conclusion that I have).
Hence, I'm also confused what am i doing wrong or... if there is an issue with the Riccardi M63...
Q1... in the RiccardiAdaptaion.pdf there is no notion of the scope. Out of this thread I understand that actually the distance may differ between the scopes (f-ratio as this determines light cone angle that enters the reducer) so that this 73.5mm is just a theory?. Do I read you Guys right?
Q2. Is there anyone working with TEC140 + small Riccardi 0.75x who could advice your own, well working distance?
Edited by Vaud, 09 September 2020 - 05:01 AM.