Spectroscopy

A basic design will be made for a script that automatically takes properly exposed arc and flat field exposure similar to the existing FIES scripts. This design should form the basis to provide these kind of scripts for the most often used spectroscopic set-ups with ALFOSC.

When acquiring a target on the slit the first step typically involves an offset in the order of 10-20 arcsec as the center of the slits do not coincide with the pointing center. As the resulting offset typically has an error of a few percent (a few 0.1 arcsecs) a second iteration is needed in basically all cases. We plan to analyse the data collected over the last few months to see if there is any systematics in the offsets so a first automated telescope offset can be done at the start of the acquisition, speeding up the process.

To avoid an imbalance of the grism wheel in ALFOSC the weight was measured for all grism-wheel items and the corresponding list on the web was updated.

To avoid having calibrations lamps being left on by accident there is a time-out which automatic switches them off after 1200 sec. However, if the lamp is switched-on again (e.g., from a script) during this time the time-out is not reset and it can occur that the lamp switches off during an exposure. This was corrected such that the time-out is reset independent on if if is already switched-on or not.

A fault occurred in which a text string was entered in the file containing the slit positions causing the alfosc.acquisition script to fail. A wrapper script was made that allows you to use a regular editor and which analyses the contents of the file when finishing editing, letting you know if everything is OK or not, and correcting some errors automatically. The script still needs to be fully checked, while it is also being expanded to include editing other set-up files.