MXU: Wrong number of slitlet keywords for CALIB data

MXU calibration frames can inherit slitlet information from calibration frames taken before for another MXU setup. If the previous setup has more slitlets than the current one, the information for the current setup is correctly written, but the surplus keywords are not deleted. Therefore the header will show a setup with too many slitlets.

Example: The current setup has 45 slitlets, whereas the previously observed setup had 70 slitlets. Then the first 45 slitlet keywords carry the correct information for the current setup, whereas the slit keywords 46 to 70 still have the information from the previous setup.

This problem does not occur for SCIENCE data and has been solved by November 13, 2006.

FORS2 LSS science observations: only 1 chip of spectrophotometric standard star observations associated

During the time August 2005 to Jan 19, 2006 we did not pack both CCD chips of the appropriate spectrophotometric standard star observation (STD_MOS), but only the one closest in time to the respective LSS science observations. Usually this was chip 1, which again usually contains the spectrum of the spectrophotometric standard. If you received instead spectrophotometric standard star observations without a spectrum you can retrieve the missing data from the archive.

LSS science observations: wrong CALIB associated

During the time July to December 2005 some LSS science data had wrong CALIB data (wavelength calibration and/or flat fields with slit widths different from those of the science data) associated to them. Correct CALIB data can be obtained from the archive for FORS1 and FORS2. PIs of affected programs have been notified.

Filename Length Problem

To display or manipulate the FITS files with older versions of IRAF (before 2.11), you can:

1. copy these FITS files to your hard-disk and rename them with filenames <= 32 characters in length,
2. create symbolic links with filenames <= 32 characters in length to your CD-ROM files.

The FITS files use the ESO HIERARCH FITS keyword extensions standard to all ESO telescopes. Note that IRAF treats all ESO HIERARCH header lines as COMMENT lines, i.e. IRAF and IDL cannot automatically interpret the information provided in ESO HIERARCH header lines.

Please note that the RA and DEC keywords are recorded in degrees. To translate these keywords so that they can be used by IRAF you have to use the asthedit task in the noao.astutil package. The help file for this task gives an example of how to translate the ESO format to the IRAF format.

Several keywords have been added to the files to make them understandable for IRAF and IDL. The main keywords are OBJECT, FILTER, GRISM, SLIT, AIRMASS, UT, ST, and IMAGETYP. These are translations from some of the hierarchical keywords. The tasks in ccdred and xccdred understand these keywords if the instrument file is set up correctly. The image sections for 4-port readouts are defined as well in the headers and are understood by the tasks in xccdred.

Data related issues

Problems may also be related to the pipeline processing or may result from features of the instrument.