Finally all the ALFOSC grisms were marked to specifically indicate the direction in which they should be mounted to avoid mistakes. The staff scripts used to align the slits and grism were converted to sequencer scripts following the general rules for the documentation and implementation of these scripts.

A web page was created which gives some some background info on the fringing in ALFOSC spectra and hints on how to observe and how to reduce the data in order to beat down fringes in red ALFOSC spectra. This can be found at:


As part of the calibration plan, the grisms efficiencies and level of fringing will be measured and the information on the webpages updated.

The procedure to put a star on the slit will be incorporated in to the sequencer system in which it will become a single streamlined target acquisition routine. We are also thinking of including the procedure to align a slit with feature in the field (e.g., 2 stars) into the same routine.

Thomas Augusteijn 2009-01-15