Multi-Object Spectroscopy

- MOS masks are now defined using our in-house developed WWW-based mask-design help (since P48), and are cut by the Italians since P49. The slit width is 1.7 arcsec. As the masks are thin, they need to be mounted with a dedicated spacer in the wheel. Pedro made several spacers according to a design by Jacob. A few runs have now been done with the new masks: the mask design and cutting is working fine. There seems a bit more cutting debris in the slits, than with the Copenhaguen setup, but sofar observers are happy.

ALFOSC Multi Object Spectroscopy (MOS) ------------------- The first observing run that used MOS masks manufactored by the TNG was=

in the end of July 2014 (49-034, Dahle). After some adjustments to the manufactoring process, the masks where successfully used for observations. A futher two MOS masks where manufactored for an observing run in early=

November, which also was successfull.

In the past we have relied on the NBI, Copenhagen, Denmark, to assist with software to design MOS masks and manufacture the masks for use with ALFOSC, but it seems clear they will no longer be able and willing to provide masks. For this reason, with have contacted the TNG, and mechanical tests were made from which it was concluded that they can provide MOS masks with well-defined slits with a width of 1.7 arcsec. Furthermore, we have developed software tools to help users design MOS masks, and define a standard way to transform the user's design to the format needed by the cutting machine. In principle, the idea is to offer this as the standard set-up for MOS observations in the future.

A new MOS-mode web page was created with more recent examples, update target acquisition procedure, and the features of the new MOS design software, while removing all references to the now obsolete MOSPLATE program.