Re: APCC move axis question

Ray Gralak

Hi Linwood and Andy,

I took a quick look at this issue, and I don't believe there is a problem with APCC. APCC is properly adding the rate supplied to it whether or not pointing and/or tracking rate correction is enabled.

However, the ASCOM driver is sending an RA movement relative to zero, which is maybe the problem. The ASCOM definition for this method is unclear if the rate should be relative to sidereal or not. It only states that the previous tracking rate should be restored when the move axis rate is set back to zero.


-----Original Message-----
From: [] On Behalf Of
Sent: Sunday, August 29, 2021 8:59 AM
Subject: Re: [ap-gto] APCC move axis question

Ray said:

You should disable tracking/pointing correction during polar alignment routines, or you may get a bad polar
alignment result.

That's a fair point, but really steps around the core issue.

As a simple example, the NINA control panel has simple N/S/E/W controls. These stop working when pointing
corrections are active. I have no idea if there are other places in other programs that also use move-axis.

Should these in fact be failing when pointing corrections are active?

I just tried a trivial example:

- Opened APCC, initialized (tracking = 0), pointing corrections disabled
- Opened NINA, connected
- Using NINA control slewed N, then S - worked fine, fast (APCC showed it slewing)
- Checked pointing corrections
- Slewed N, S - no motion. Only thing I saw on APCC (or maybe ASCOM V2) was flickering from custom to
sidereal rates as I pushed the button

This itself is hardly an earthshaking issue since I can just use the APCC controls to slew (if my sleep deprived
brain can remember in the wee house), but it does bring with it a concern that other features of NINA or other
software connecting via ASCOM my not work.

Or is everyone pretty sure this is a very isolated case and nothing else uses move axis?

Or are you saying that Move Axis itself, if allowed, would break the pointing model?


PS. Logs available if desired from that brief test.

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