magore However there are positions on the sky that give more optimal results mathematically speaking for this initial calibration to be most accurate.
Calibrating close to the celestial equator makes it easier to adapt to other declination angles. Calibrating close to the pole creates large errors (reciprocal of cosine of an angle close to 90º) when used for other declinations. Notice too that it will take forever to move 25 pixels when calibrating in the East-West direction when calibrating near the pole.
Calibrating close to the meridian minimizes the error from atmospheric refraction.
So, the best place to calibrate is at declination = 0º (i.e., celestial equator) and RA = LST + a little bit, so that the mount doesn't stop when tracking reaches the Meridian limit. (RA = LST when the OTA points to the Meridian).
Just look at the Local Sidereal Time (LST) clock, add 15 minutes to an hour to it, and use that as the RA for a GOTO, with declination set to 0º. Takes well less than a minute to do that with ASIAIR -- no need for automation.
ASIAIR does not understand the horizon based coordinate system, otherwise it is simple to set up a "Favorite" position to slew to. For now, just use the LST to determine the calibration location, using the equatorial coordinate system.
Chen
