ABSTRACT:Routines to calculate airmass
C ROUTINE CALLED: atAirmassFind in atAirmass.c
Calculate the airmass at APO given the RA in degrees, the DEC in degrees, a UT timestamp.
TCL SYNTAX: airmassFind "<ra>" "<dec>" "<ut>" TCL HELP STRING: Find the airmass of an object at RA,Dec, at time UT. Finds airmass at epoch of coordinates, at the latitude of APO. TCL ARGUMENTS: : "<ra>" : right ascension in decimal degrees "<dec>" : declination in decimal degrees "<ut>" : tstamp object
C ROUTINE CALLED: atAirmassFromZd in atAirmass.c
Nothing but a wrapper to sla_Airmas which takes a zenith distance. This is specifically for use when one might be tempted to simply use sec(z), which will incur 0.25% errors at the Survey limit without any real good reason for doing so.
TCL SYNTAX: airmassFromZd "<zd>" TCL HELP STRING: Find the airmass of an object at Zd. TCL ARGUMENTS: : "<zd>" : zenith distance in decimal degrees
C ROUTINE CALLED: atMeridianAirmassFind in atAirmass.c
Calculate the meridian airmass at APO the DEC in degrees.
TCL SYNTAX: meridianAirmassFind "<dec>" TCL HELP STRING: Find the meridian airmass of an object at Dec. Finds airmass at epoch of coordinates, at the latitude of APO. TCL ARGUMENTS: : "<dec>" : declination in decimal degrees
C ROUTINE CALLED: atAirmassFindHaDec in atAirmass.c
Calculate the airmass at APO from the HA in hours and the DEC in degrees.
TCL SYNTAX: airmassFindHaDec "<ha>" "<dec>" TCL HELP STRING: Find the airmass of an object at Ha,Dec. Finds airmass at epoch of coordinates, at the latitude of APO. TCL ARGUMENTS: : "<ha>" : hour angle in hours "<dec>" : declination in decimal degrees
C ROUTINE CALLED: atZdDec2Ha in atAirmass.c
Calculate the HA (hours) from the zenith distance (degrees) and dec (degrees).
TCL SYNTAX: zdDec2Ha "<zd>" "<dec>" TCL HELP STRING: Find the HA given ZD and DEC Finds HA at epoch of coordinates, at the latitude of APO. TCL ARGUMENTS: : "<zd>" : zenith distance in degrees "<dec>" : declination in degrees