There are times when the TCS does not collect information about an image, and hence, your image headers may not have all required information. You can see if your headers have the required information by typing in the iraf terminal:
cl> hsel obj*fits $I,RA,Dec,filter yes
In this example, "obj2251.fits" does not have the RA, Dec, or filter in the header.
Before you do anything, make sure to save a copy of the original image.
You may use the iraf task "hedit" to update the parameters. Make sure to edit every single extension on your image.
You may download the task 'repairhdr' that will fix your headers as well. The advantage with downloading this tasks is that you only have to type one command, and then all 8- or 16-extensions will be updated.
The task "repairhdr" is a general task that can be used to fix any additional header information.
Download repairhdr here
run the task
Place the task in a directory and make note of where you have saved it. (e.g.: /Users/mydownloads/)
Go to the directory that your images are in:
> cd /Users/myname/DATA/
Define the task:
> task repairhdr = /Users/mydownloads/repairhdr.cl
Call the task to update any fields:
> repairhdr obj2251.fits RA 06:45:53.74 ver-
> repairhdr obj2251.fits DEC -45:10:06.70 ver-
> repairhdr obj2251.fits filter "g SDSS c 6017" ver-
Page created: February 2011 by Andrea Kunder