Spectroscopy

With the help of Michael Andersen some investigations were made in the possibility of acquiring other high-efficiency VPH grisms. According to estimates by Michael, new VPH grisms with a peak efficiency of $\sim$85% can be purchased for about 2000 Euro a piece. It would be possible to replace the R$\sim$700-1000 grism set (#7,#8,#14 and #16) and the current Echelle mode (R$\sim$2000) but it is not yet clear how the efficiency (and therefore the relative gain) of these grisms vary as a function of wavelength.

The VPH grism that was purchased is square and needs a special holder. Discussion have been going on with CUO about the design.

Various parts of the spectroscopic calibration plan have been implemented during the semester to monitor the instrument and help with setting-up the instrument. Part of these results will also be used to improve the quick-look reduction provided at the telescope. Related to the monitoring of the instrument, a new automated interactive data reduction for spectroscopic flux-standards was made.

Instructions on balancing the grism wheel when mounting grisms were made to avoid possible problems with the wheel.