approx_altaz2pa

rubin_sim.utils.approx_altaz2pa(alt_deg, az_deg, latitude_deg)

A fast calculation of parallactic angle

Parameters:

alt_radfloat

Altitude (degrees)

az_radfloat

Azimuth (degrees)

latitude_radfloat

The latitude of the observatory (degrees)

Returns:

pafloat

Parallactic angle (degrees)