Data Reduction Frequently Asked Questions

How does the pipeline choose where on the slit to extract the spectrum in long slit mode?

The FORS2 data reduction pipeline extracts a spectrum for each object it detects within the LSS slit. As all spectra will be in a single fits file, the main FITS header does not contain the data for the extraction parameters. The extraction limits are written by the pipeline to a table with type OBJECT_TABLE_SCI_LSS, which contains for each detected objects the start and end rows in the raw frame, which should allow you to identify which is the extracted spectrum for your target.