### astSetRefPos

Set the reference position in a specified celestial coordinate system

#### Description:

This function sets the reference position (see attributes RefRA and RefDec) using axis values (in radians) supplied within the celestial coordinate system represented by a supplied SkyFrame.

#### Synopsis

void astSetRefPos( AstSpecFrame $\ast$this, AstSkyFrame $\ast$frm, double lon, double lat )

#### Parameters:

##### this
Pointer to the SpecFrame.
##### frm
Pointer to the SkyFrame which defines the celestial coordinate system in which the longitude and latitude values are supplied. If NULL is supplied, then the supplied longitude and latitude values are assumed to be FK5 J2000 RA and Dec values.
##### lon
The longitude of the reference point, in the coordinate system represented by the supplied SkyFrame (radians).
##### lat
The latitude of the reference point, in the coordinate system represented by the supplied SkyFrame (radians).