OBJRATIO

Name

objratio

Purpose

Ratio object spectra to one or more comp star spectra.

Description

Ratio object spectra to comp stars, combined appropriately to
match object airmasses. For a single comp star, obviously you
just get a simple ratio - no real airmass correction. For two
or more comp stars, an extinction is derived, and used to correct
each comp star spectrum to the object airmass, prior to averaging
the comp stars and performing the ratio. If the /NOEXT keyword
is set, no extinction correction is derived or applied.

Calling Sequence

objratio, calib, object, o_am, o_times, comps, c_am, c_times, ratio

Required Inputs

object: Array of object spectra [spectrum number, pixel number].
o_am: Array of object airmasses.
o_times: Array of object mid-point exposure times.
comps: Array of comp star spectra [spectrum number, pixel number].
c_am: Array of comp star airmasses.
c_times: Array of comp star mid-point exposure times.

Optional Input Parameters

Keyword Input Parameters

O_BAD: Array of badflags for the object spectra.
C_BAD: Array of badflags for the comp star spectra.
NOEXT: Force simple averaging (disable airmass correction).

Outputs

ratio: Array of ratioed object spectra, same size as object array.

Keyword Output Parameters

R_BAD: The resulting badflags in the ratio spectra.

Optional Output Parameters

Common Blocks

None.

Side Effects

Extinction plot is plotted to window 0.

Restrictions

Procedure

Currently, the times are ignored, but including them gives us the
option of later doing an elaborate solution for extinction changing
as a function of time, with a whole slew of comp stars, by changing
only this single routine. Otherwise we'd later have to track down
and change all the instances where this routine is invoked.

Modification History

1998/07/12 WG Created by Will Grundy, Lowell Observatory
1998/07/15 CDP Changed program to accept the spectra as [pixel number,
spectrum number]
1998/07/17 CDP Added badflag filtering and creation for ratios
1998/08, MWB, Rewrote extinction calculation.
1998/09/08 WG Generalized so that more than 2 comp stars can be
used and added /NOEXT keyword.
1998/09/09, MWB, Rewrote error checking and changed calling sequence.