Here I describe the formulas that are related to the pointing model implemented in schierd for the ROTSE-III telescope. This is for quick reference only, and details can be found in the Tpoint manual.
Declination index error in an equatorial mount: the zero-point in .
Hour angle index error in an equatorial mount: the zero-point of .
In an equatorial mount, if the polar axis and declination axis are not exactly at right angles, east-west shifts of the image occur that are proportional to .
In an equatorial mount, the collimation error is the non-perpendicularity between the nominated pointing direction and the declination axis. It produces an east-west shift that is constant for all declinations.
Vertical misalignment of the polar axis of an equatorial mount: a rotation about an east-west axis equal to coefficient ME.
Misalignment of the polar axis of an equatorial mount to the left or right of the true pole: a rotation about an axis through ( ) equal to coefficient MA.