Parameters for "chkhead"

An epar to the task chkhead will look like this:

Parameters for chkhead

The task "chkhead" will simply use hselect to extract some critical
parameters from the image headers and list the results on the screen.

Make sure that the various task parameters ("ut", "date-obs",
"exposure", "ra", "dec", "ha", "st", "epoch", "filter", "aperture",
"grism", "tel") are set to the header keywords of the images
that you want to reduce.

The task will check that the headers contain all the data that
are needed for subsequent reductions, and present you with a
listing of the relevant parameters. Check that all the parameters
make sense.