Re: Understanding automation-based corrections/sync #Mach2GTO #Keypad


Dale Ghent
 

On Jun 19, 2021, at 22:18, deonb <deonb@outlook.com> wrote:

Thanks Dale,

I'll try tonight with the 'prevent syncing' on in N.I.N.A. I figured N.I.N.A does something simple like this - and that does seem to me that it could cause cumulative errors - through no fault of NINA.

Out of curiosity - if sync is turned off, how does NINA center after plate-solve? Does it then just slew to offset coordinates instead? (And will those thus instead be reflected in the FITS file?)

Either way, I'm looking more for an overall safety from the APCC side here. Even if the 'prevent syncing' solves the specific NINA case, I still want APCC to prevent NINA, Stellarium, PHD2 or whatever from deviating the overall correction to more than e.g. 0.5 degree from the A.E.
I'm confused by what your goal is here - it sounds like you still want centering in some form, but on the other hand you want the mount to be authoritative, which means the centering operation becomes superfluous and should be removed or turned off entirely.

I think the main question here is why or how is this gross deviation working its way into the system in the first place. Normally a centering operation will plate solve and check the solved coordinates against the target's coordinates and sync+reslew to the target coordinates if they are outside your Pointing Tolerance, which is configured under Options > Plate Solving in NINA. In other apps this is referred to as a "close loop slew."

With an encoder mount and especially with a pointing model, this centering check should essentially be a no-op as your mount ought to be spot on at any given time and certainly within NINA's default pointing tolerance, which I think is 1 arcmin. The only time when this isn't the case is if your model is screwed up, your Observing Conditions temperature measurements are in F instead of C like with Wade's recent experience, or your polar alignment is off. There are probably some other perturbations to the system that can throw things off, but APCC logs would probably help sort that out.

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