Instrument

The exposure command used with the exposure meter in FIES takes as input the total counts wanted from the meter at which the exposure should stop, and the maximum exposure time where the exposure will be stopped if the total count from the meter has still not been reached. The input value for the total counts for the exposure meter is a very large number typically in the order of 10 million where it is easy to add or forget a digit. To reduce any possible problem the option `-m' was added to the exp-count command which will interpret the number given as millions. A warning is given in the value is not in the range 0 to 300.

The fies.easythar used for standard wavelength calibration exposures with the ThAr lamps was upgrade to allow the user to scale-up the exposure time with respect to the standard exposure time. This allows to overexpose the few bright lines, but bring up a forest of many fainter lines. This is useful for high-precision radial-velocity work.

Often at the start of the night when using FIES one is only waiting for the sky to get dark enough so the autoguider TV camera can be switched-on to start observing. More in general, when observing (very) bright targets the sky background is not really important for observations with FIES, but it can limit the use of the autoguider. Furthermore, as StanCam provides fiber viewing there is no absolute need to be autoguiding to be able to observe with FIES. The plan is to defined what are the precise requirements to allow for observations with FIES without using the autoguide camera. In particular, the target acquisition should also be possible when not guiding, while the system used to position and keep the target in the fiber should also function (properly) when not guiding. Based on the requirements we will consider implementing this option.

We hope to receive and commission the polariser in the coming months.