Variables and Functions

OBS being based on SIC includes Variables and Functions which can be used to tailor observing procedures.

Two important variables exist

• DSUN the distance to sun corresponding the time implied by the last call to function ELEV, or the last OBS $\backslash$SOURCE command. It can be used to check Sun avoidance.

• SCAN the next scan number.

Three functions have been implemented

• ELEV(Dm) Returns the source elevation in degrees Dm minutes from current time (ELEV(0) is the current source elevation). A call to ELEV updates the DSUN variable.

• UT() Returns the current UT in hours.

• LST() Returns the current LST in hours.