On the first night, we take a direct image of the field in 2 or more filters. Meanwhile, we keep observing other fields. An aperture mask is designed from a priority list of objects based on magnitude, color, and position. The mask is fabricated real-time at the telescope using a laser. Our nights are usually scheduled in advance to the minute, and we strive for the most efficient use of telescope time possible.
C lick here for some pictures from our last run.
Back home, the imaging data are used to create final multi-color catalogs across many individual CCD fields. Spectroscopic observations are reduced and cross-correlation techniques are used to determine redshift and spectral type identifications. Further analysis yields line spectreal line indices for a more detaile d look at the star formation histories in the galaxies. You can find out more about some of our reductions software here . Click on the images to see legible, full-resolution versions.