Contents

The grism specification file, grismspec.dat, defines the filters and grisms Calnic C recognizes and the parameters Calnic C assumes for each of them. It is found in the $CALNICC_BASE/calib directory.

The file is read by Calnic C and specifies a keyword to read the name of the filter or grism. For each recognized name, it list then:

1.

whether the image is a direct image or a grism image

2.

in case of a grism image

• the position of the spectrum in dispersion direction
• the dispersion relation of the grism
• the distortion of the spectra
• the offset of the spectrum relative to the direct image
• a 3d flatfield (FITS) file to be used for flatfield correction
• a file which defines the convolution kernel for object detection
• a FITS file containing image background data
• a file which defines the filter response curve

3.

the FITS file with the appropriate PSF for the direct image or grism used to identify objects.