Re: Interactions Between Keypad and APCC Orthogonality Models? #APCC #Mach2GTO #Keypad

Roland Christen

The CP4/5 controllers are totally independent of anything that APCC does. APCC models are not loaded into the CP controllers.

The way it works is like this:

1) if you do NOT create an Ortho model with the keypad, then APCC models will naturally create their own and compensate automatically for any non-orthogonality.

2) if you first create an Ortho model with the keypad, that model will be loaded into the mount's CP servo controller and will therefore be active at all times. If you then create a pointing model with APCC, it will simply respond to the way the mount now points more accurately and will naturally not have an ortho model built into its own model.

An ortho model that is created using the keypad will reside in the mount's controller at all times and be active from then on, regardless of power cycles. If you change the scope to something different that has a different orthogonality error, then you simply run the ortho routine for that setup.

If you first model a new setup with APCC and then create a new ortho model with the keypad, then you will have two orthos that will negate each other.


-----Original Message-----
From: John Upton <upton@...>
Sent: Tue, Sep 14, 2021 9:56 pm
Subject: [ap-gto] Interactions Between Keypad and APCC Orthogonality Models? #Mach2GTO #APCC #Keypad

Hi all,

   I am looking for some clarifications regarding the interactions / interoperability of the Ortho Model performed by the Keypad versus the pointing model created by APCC? The questions I want to understand are:

  1. I assume the APCC model takes precedence when a Keypad Ortho Model has been built. Is that correct?

  2. Does the APCC model erase the results of the Keypad Ortho Model or simply override it?

  3. If the APCC pointing corrections are turned off, does the most recent Keypad Ortho Model once again take effect or does a new one need to be built?
   For some observing and simple single object imaging sessions, I think I would like to just have the orthogonality error corrected without creating / running a normal pointing model. It would simplify / speed up plate solving on both sides of the meridian. Ideally, for a quick portable imaging session, I would prefer not to have to rerun the Keypad Ortho Model at the beginning of each session when I don't want to run APPM. I will be guiding for these sessions and since they involve only a single target, plate solving will suffice for the evening's only target.


Roland Christen

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