Sidereal tracking rates for Mauna Kea
In testing the performance of antenna servo systems for low velocity tracking (at the specified minimum smooth velocity), it
is useful to know the directions in the sky where the tracking velocity crosses zero. For elevation this is simple: at transit (az=0 or 180), but
for azimuth it is more complicated. The azimuth tracking rate goes to zero only for objects that transit between the zenith and the celestial pole.
Using the equations from the CBI website
, here are plots of the
locations of zero crossings in the azimuth sidereal tracking velocity from Mauna Kea. Click the image for a larger version.
The following plots show the azimuth tracking rate for 16 minutes centered on the zero crossing for 6 different declinations
between the zenith and the celestial pole:
The following plots show the elevation tracking rate for 16 minutes centered on transit for 15 different declinations.
The associated C programs and python scripts that generated these plots are attached below.