ALT-AZIMUTAL Telescope concepts

This page aims at reviewing the 3 fondamental motions of an Alt-Azimutal telescope : Altitude, Azimutal and Paralactic motions.
These three motion are not constant like the sidereal rate, because the sidereal motion is splitted into three motion of the Alt-Az base that implies non linear trigonometrics transformations. Hereafter are the plots of the meridian angle (hours) versus Alt, Az and parallactic angle. To get the speeds, you have ethier to take the slope of the curves or to have a look to the speed curves (done later).

Altitude versus Meridian angle (in hour), 0h is the meridian. Plots according to declinaison from DEC= -45 to +82.

Azimuth versus Meridian angle (in hour), 0h is the meridian. Plots according to declinaison from DEC= -45 to +82.

The parallactic angle defines the angle between the Celestial pole, the star and the zenith.

Paralactic angle versus Meridian angle (in hour), 0h is the meridian. Plots according to declinaison from DEC= -45 to +82.

For a DEC=Latitude, this is a singular case nearby the Zenith, here it involves high speeds of Azimuth and Parallactic angle.