approx_ra_dec2_alt_az

rubin_sim.utils.approx_ra_dec2_alt_az(ra, dec, lat, lon, mjd, lmst=None)

Convert Ra,Dec to Altitude and Azimuth.

Coordinate transformation is killing performance. Just use simple equations to speed it up and ignore aberration, precession, nutation, nutrition, etc.

Parameters:

raarray_like

RA, in degrees.

decarray_like

Dec, in degrees. Must be same length as ra.

latfloat

Latitude of the observatory in degrees.

lonfloat

Longitude of the observatory in degrees.

mjdfloat

Modified Julian Date.

lmstfloat (None)

The local mean sidereal time (computed if not given). (hours)

Returns:

altnumpy.array

Altitude, same length as ra and dec. degrees.

aznumpy.array

Azimuth, same length as ra and dec. degrees.