geometric correction

Forums Spectroscopy Unable to calibrate a spectrum in ISIS geometric correction

Robin Leadbeater

Hi John,

See answer #9 above for the source of the problem.  Actually, I see now that the slant of the lamp  lines is partly because the dispersion is not exactly horizontal, as seen in the star image.  If next time you rotate the camera to make the star spectrum horizontal, the calibration might run ok without needing to change the X position entered or adjust the grism.