Re: TPoint vs. APPM -- Translation Possible?


T-point cannot provide dual-axis tracking with AP mounts…only APCC can do that.






George Whitney

Astro-Physics, Inc.

Phone:  815-222-6538 (direct line)

Phone:  815-282-1513 (office)

Email:  george@...


From: <> On Behalf Of mjb87 via
Sent: Tuesday, November 2, 2021 8:28 AM
Subject: [ap-gto] TPoint vs. APPM -- Translation Possible?


I use APPM with great results on my Mach2 with the 130mm refractor. I have been unable, after a year of effort, to build a APPM model on my 1100 with the 300mm f/15 Cassegrain. The FOV and the pixel size is just too small to get plate-solving to work reliably. Yes, I've tried focal reducers, different databases, different cameras, etc., etc. When I do get solutions they don't make sense,e.g., 7 degree orthogonality difference whereas ConeSharp says it is about 10 arc-minutes.

I can easily build a TPoint model using TSX for that setup by visually aligning the stars selected. Took me 40 minutes last night to build a 24-point model.  However, that locks me into using TSX, with the tracking/pointing in APCC turned off. There are time I may want to taker TSX out of the loop. Note: I am looking primarily for pointing accuracy as opposed to tracking accuracy with this setup since I do not do long-duration unguided imaging. It is mainly planetary and visual work.

So the question: is there any way to translate the TPoint results into an APPM model?  I suspect not, but had to ask. Alternatively, is there any way to to manual star alignments in APPM instead of using plate-solving?


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