On Sun, Mar 8, 2020 at 05:31 PM, uncarollo2 <chris1011@...> wrote:
1) Polemaster does not necessarily insure good polar alignment. Only drift alignment can reduce drift.
2) Having perfect polar alignment does not insure zero drift due to atmospheric refraction
3) doing a drift alignment can produce zero drift for both RA and Dec if you use the right method, but this zero drift will only occur in the area around the zenith. In other parts of the sky the stars do not move at sidereal rate, and will also drift slowly in Dec. This is fundamental, and no amount of polar alignment will prevent drift.
4) In our new keypad software we have added the King rate which reduces the RA drift in those parts of the sky where the sidereal rate is incorrect, however the King rate does not address Dec drift. We have modeling software in the new keypad which can be used to compensate for drift in both axes, and can allow unguided imaging. You can also go full model with APCC Pro, but I would recommend using that for permanent setups where you can spend some time getting a really good all-sky model.
In looking at my graph without guiding input, the center of my RA trace drifted around 6.25 arc seconds in 11 minutes (in RA). In DEC, the trace shows only about 3.75 arc seconds of drift in 11 minutes. The peak to peak of the each graph was similar, and more than 2.5 arc seconds P-P. I sent this to you in a screen shot. I expect this is telling me that the seeing was poor at best, based on these values. I was still getting round stars (while actively guiding). Such is life in Vermont under the jet stream!
I'm happy to report that I've successfully installed APCC, and set it up and at least tested it out without any clear sky. Everything connects as it should. Called George today, who was very helpful, to provided guidance on some of the finer points. Now just waiting for clear skies.