Spectroscopy

The script to acquire a target on the slit now allows for an additional step where the user can do a manual telescope offset to fine-tune the centering of the object in the slit. Due to the asymmetric design of ALFOSC, there is some variation in the position of the slits due to flexure, and especially for narrow slits this option is of use.

It was mentioned that regular programs often requested the 5 arcsec slit, while the 10 arcsec slit is part of the fixed set-up for ALFOSC needed for some ToO programs. Also, the 1.2 arcsec slit effectively has the same with as the 1.0 arcsec slit, which is also part of the fixed set-up. Sometimes requests for the 1.2 or 5 arcsec slit generated conflicts between the set-up for the regular program and for ToO programs. There seems no specific difference or advantage for spectroscopic observations in using the 5 arcsec slit instead of the 10 arcsec slit, while there is no real practical difference between the 1.0 and 1.2 arcsec slit, and it was decided to no longer offer these slits. Any mention of the slits was removed from the ALFOSC ``slits'' web-page. In the ``List of available optical elements'' the slit has been labelled as 'decommissioned'. Note that the slits are of course still available if need be.