All arguments for these procedures and functions can be arrays. All require
existence of GeoParms variable. A default can be created by using
`get_geoparms`

`utc2ut1`(*utc*_real)

Function. Returns UT1 in seconds, with UTC input in seconds.

Function. Returns GST in hours, inputs are in seconds.

Function. Return hourangle in hours, with inputs also in hours.

Function. Return zenithangle in degrees with inputshain hours anddecin degrees.

Function. Return mirrorangle in degrees with inputshain hours anddecin degrees.

Function. Return equatorial coordinates for input horizontal coordinates X=east, Y=north, and Z=up.

Function. Return horizon coordinates for input equatorial coordinates X=projection of local meridian on equator, Y=east, and Z=north.

Function. Return horizon coordinates for input azimuth and elevation angle in degrees.No GeoParms required.

Function. Return hour angle in hours and declination in degrees for input equatorial coordinates.No GeoParms required.

Compute apparent declinations and right ascensions for a list of times (in seconds UTC) and corresponding stars. (The arraystimeandstarshave to have the same number of elements therefore.) The startable is a standard STARBASE startable. The geoparms structure has to be loaded.

Procedure. Compute astrometric variables in scans structure.

Procedure. Compute estimated visibilities, i.e. normalized visibilities.

Change reference station for data of specified class (default all classes) tostation.

Precess J2000 position angles (theta) to current Julian Year epoch (jy) for direction=1, from current to J2000 for direction=-1. (see: Heintz, "Double stars", p. 33). Input theta is in radians, dec in degrees, ra in hours; output is in radians.