Target acquisition

FIES acquisition (StanCam)

- We experienced an unscheduled StanCam warmup in May. CP: Stancam got done alcohol 96 flushing in the cool head. Used vacuum pump to suck it, later nitrogen gas to dry. The supply hose was changed to avoid contamination after the head was cleaned.

However, another warmup occured in August. Well, two warmups per semester is not so bad, given the history.

With the new Tiger installed Oct 2013 we still have had 2 'emergency' pumpings in the two following semesters.

- The adapter pick-off mirrors were cleaned during aluminisation: guider, STANCAM, FIES

- added SDSS g' to the standard set for fiber viewing, as the Bessel B throughput is affected by the blue-less transmission of the re-imaging optics. SDSS g' is a good filter for faint blue targets, and the Bessel B remains for very bright stars that would overexpose in all other filters.

StanCam is used to image and center targets to be observed with FIES. Depending on the colour and faintness of the target, different filters or a clear filter can be used. For faint blue sources there is a bit of a problem. The Bessel B filter that is used largely overlaps with the cut-on of the glass used for the optics to re-image the fiber head on to the StanCam detector. For bright stars this combination gives an excellent attenuation, but for faint stars it is less optimal. To remedy this, a SDSS g-filter was tested and found to give better results. This filter is now added to the filter set that is permanently installed in StanCam.