Instrument

In the coming period we plan to make baffles around the Halogen lamp vent in the calibration unit at the telescope to block light pollution of the dome. We also plan to test and install an exposure meter inside FIES which is being developed and build by people in Aarhus.

One thing that was noted is that when using the simultaneous-ThAr mode there is an issue of contamination of the stellar spectrum by the (strong) arc lines when the star is not very bright. It should be investigated what is the optimal solution as a function of the signal in the stellar spectrum and the arc spectrum, the stellar spectral type (e.g., early type stars have very few lines), and the required accuracy.