NAME
skyflat
SYNOPSIS
skyflat tarid= logid= [optimum=]
DESCRIPTION
This procedure does the special things needed to
create a sky flat field image.
- runs openup
- If at dusk, it points telescope 10 degrees east of zenith
- If at dawn, it points telescope 10 degrees west of zenith
- turns off telescope tracking
- For each PictureID it takes an image
- With specified Filter
- Uses ExposureTime, Binning, and Amplifier
- Repeats Picture.Count time jogging telescope a degree or so
- Writes FITS file with detailed header
canonical name
- sets IMAGETYP to 'FLAT'
The program attempts to adjusts the exposure time so that
the mean signal level (above bias) is OPTIMUM.
The value of OPTIMUM can be optionally set on the command line
or the default viewed in the code below.
If the exposure is too short, the program exits.
If the exposure is too long, the program exits.
An earlier version of this procedure waited for it to get dark.
See the source code for the definitions of MAXTIME and MINTIME.
The XVista routines of sub and
mn are used to perform image
arithmetic.
INPUTS
Observer.Name
Picture.ExposureTime
Picture.Binning
Picture.Amplifier
Picture.FilterID
Picture.Count
Procedure Index