Commissioning report for ESO

Vik Dhillon, version: 19 December 2006

ULTRASPEC was awarded 4 nights of technical time by the Director of La Silla-Paranal Observatory for use on the EFOSC2 spectrograph mounted at the Cassegrain focus of the ESO 3.6-m telescope. The time was scheduled from Dec 1-4, 2006. This document presents a brief report on the commissioning run and describes how we used the telescope time. For an overview of ULTRASPEC and how its hardware and software work, please consult the commissioning plan.


  1. A photo diary
  2. Observations
  3. Summary

A photo diary


We were awarded 4 nights of technical time by the Director of La Silla-Paranal Observatory. One of these (2006 December 1) was used for setting up EFOSC2 and has been described in the photo diary above. In this section, we report on the 3 nights of observations, 2006 December 2-4.


The ULTRASPEC commissioning run was a great success. Installation, integration and alignment proceeded without problems, no telescope time was lost due to technical problems with ULTRASPEC, and we completed the characterisation of the EMCCD chip with a spectrograph on the sky. This latter task was the main aim of our run and is a deliverable for OPTICON, who funded the ULTRASPEC project. As an added bonus, we were also able to observe two demonstration science objects, which will serve as useful examples to the community on the power of EMCCD's for astronomical spectroscopy. The results, which show that EMCCD's are likely to revolutionise certain types of (i.e. readout-noise limited) astronomical spectroscopy, will shortly be submitted for publication in both the ESO Messenger and a major research journal.

With ULTRASPEC successfully commissioned, we are now keen to start using it to do science. There is little additional work to be done on ULTRASPEC in preparation for this, although we would like to investigate the purchase of one or two new grisms for EFOSC2, with higher resolution and/or better-matched central wavelengths for ULTRASPEC's smaller CCD. We would also request that, if successful in winning science time, ULTRASPEC is scheduled at the start of an EFOSC run. This would give us much more (day) time to install and align the instrument and hence save up to a night of observing time for setup.