The Vatican Observatory Research Group and the Centre for Astronomy, National University of Ireland Galway (NUI Galway), renewed a memo of understanding whereby the Galway Ultra Fast Imager (GUFI) would be located at VATT for another year starting on June 1st, 2010. The installation of this L3CCD instrument, based on a DV887 iXon Camera, with practically zero deadtime between exposures, was described in last year’s Annual Report. Leon Harding (NUI Galway) and Richard Boyle, S.J., have used Camera GUFI extensively in the fall of this year.
This year the VATT engineering staff (Franz, Harvey, Johnson, and Duffek), with input from Corbally, have been finalizing software and hardware on the new Spectrograph. Major challenges were found in modifications needed to the slit design, the grating rotator table, and the camera focus mechanism. The team transported the VATT Spectrograph to the Telescope this summer for trial tests on fitting, using the handling fixture, Derotator balancing, and slit view guiding. We succeeded in mounting the Spectrograph and balancing the Telescope and Derotator.
Problems we encountered there were few but none the less head scratches. The guide box welds interfered with VATT Spectrograph’s mounting flange and the slit stage mirrors were not aligned. A field modification to the Spectrograph mounting flange with a grinder solved the interference problem. The guide camera and VATT 4K-CCD controllers had to be re-located due to the controllers occupying the same mounting location as the Spectrograph. After many discussions the engineering team formulated a cautious plan to move the controllers, keeping in mind balance issues and aligning the guide box mirrors.
Our custom made instrument handling fixture worked great. We were able to hoist the instrument into place with full control over the x, y, and z positions.
At this point we were ready for guiding tests. However, due to weather this summer we were only able to get on the sky for a couple of minutes. This was just enough for a successful guide test. It turned out that the temporary, hand polished slit was sufficient for guiding.
We brought the VATT Spectrograph down for final assembly and alignment. In the final months of the year, we are testing the performance of the Spectrograph in the lab with the science camera before we commit to commissioning the instrument on the Telescope. If all goes according to schedule, we should be in commission mode in January, 2011.
Sloan Filter Set
A significant contribution was made by the Department of Physics at the University of Notre Dame to help observations at VATT. In consultation with Peter Garnavich (UND), a regular user of VATT who had promoted this gift, and Rolf Jansen (ASU) it was decided to put the $10,000 towards the purchase of a set of the Sloan Digital Sky Survey u’, g’, r’, i’, z’ filters. They came from Asahi Spectra Company, Ltd., in Japan and were a special order of 3.48” x 3.48” square filters with a uniform thickness of 5 mm. Corbally conducted the bidding process and purchase, while Franz arranged for holders to mount the filters in the VATT guide box. The Sloan filters were commissioned at VATT by Jonathan Stott, in December 2010.