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ccdhedit noao.imred.ccdred



ccdhedit -- CCD image header editor


ccdhedit images parameter value


List of CCD images to be edited.
Image header parameter. The image header parameter will be translated by the header translation file for the images.
The parameter value. If the null string ("") is specified then the parameter is deleted from the image header, otherwise it is added or modified. If the parameter is "imagetyp" then the value string giving the CCD image type is translated from the package CCD type to the instrument specific string.
type = "string"
The parameter type. The parameter types are "string", "real", or "integer".


The image headers of the specified CCD images are edited to add, modify, or delete a parameter. The parameters may be those used by the ccdred package. The parameter name is translated to an image header parameter by the instrument translation file (see instruments ) if a translation is given. Otherwise the parameter is that in the image header. If the parameter is "imagetyp" the parameter value for the CCD image type may be that used by the package; i.e. dark, object, flat, etc. The value string will be translated to the instrument image string in this case. The translation facility allows use of this task in an instrument independent way.

The value string is used to determine whether to delete or modify the image parameter. If the null string, "", is given the specified parameter is deleted. If parameters are added the header type must be specified as a string, real, or integer parameter. The numeric types convert the value string to a number.


The ccdred package is usable even with little image header information. However, if desired the header information can be added to images which lack it. In all the examples the parameters used are those of the package and apply equally well to any image header format provided there is an instrument translation file.

1.   cl> ccdhedit obj* imagetyp object
2.   cl> ccdhedit flat* imagetyp flat
3.   cl> ccdhedit zero* imagetyp zero
4.   cl> ccdhedit obj0![1-3]* subset "V filter"
5.   cl> ccdhedit obj0![45]* subset "R filter"
6.   cl> ccdhedit flat001 subset "R filter"
7.   cl> ccdhedit obj* exptime 500 type=integer

8. The following is an example of a CL script which sets the CCD image type, the subset, and the exposure time simultaneously. The user may expand on this example to include other parameters or other initialization operations.

    cl> edit

    # Program to set CCD header parameters.

    procedure ccdheader (images)

    string	images			{prompt="CCD images"}
    string	imagetyp		{prompt="CCD image type"}
    string	subset			{prompt="CCD subset"}
    string	exptime			{prompt="CCD exposure time"}

	    string	ims

	    ims = images
	    ccdhedit (ims, "imagetyp", imagetyp, type="string")
	    ccdhedit (ims, "subset", subset, type="string")
	    ccdhedit (ims, "exptime", exptime, type="real")

    cl> task
    cl> ccdheader obj* imagetyp=object subset="V" exptime=500

9. The image header may be changed to force processing a calibration image as an object. For example to flatten a flat field:

    cl> ccdhedit testflat imagetyp other
    cl> ccdproc testflat

10. To delete processing flags:

cl> ccdhedit obj042 flatcor ""


hedit, instruments, ccdtypes, subsets

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