Data Reduction Frequently Asked Questions

How good is HAWK-I astrometry and how are PSF variations corrected?

At present the pipeline applies a correction for PSF distortions based on a distortion map derived during HAWK-I commissioning back in 2008. Distortion images are regularly taken, but not processed. At present, the solution is to extract photometry on a chip-by-chip, exposure-by-exposure basis, derive astrometry from 2MASS on each single chip and single exposure, and the merge all the frames together.
Most of the present HAWK-I pipeline limitations will be cured in an upcoming release of the pipeline.