THE UNITED KINGDOM INFRARED TELESCOPE
ANNUAL REPORT
1995 AND 1996

4. Report on Operations

4.4. Instruments

4.4.3. IRCAM3 (1-5m camera with 256256 array)

IRCAM3 was used for nearly half of the nights assigned to common user instrumentation during 1995 and 1996 and served as UKIRT's workhorse instrument during a few lengthy periods of CGS4 engineering, most notably in spring 1995. IRCAM3 observing modes used during 1995 and 1996 were direct imaging, Fabry-Perot imaging, imaging polarimetry, and Snapshot. The 2 and 5 magnifiers were used occasionally, although their usage results in excess background radiation on the array, particularly in the thermal infrared.

Overall reliability of the IRCAM3 was remarkably high with only a period of electronic pickup and striping in early 1995, non-fatal mechanical problems with the filter wheel in early 1996, one failure of the closed cycle cooler in late 1996, and occasional data transfer errors, causing significant amounts of lost time. The latter appear to be a feature of the transputer-based ALICE system and are manifested mainly when the frequency of array readout is high, as for thermal imaging and Snapshot. Efforts to limit lost time by speeding up the recovery from this problem have made progress and are continuing.

Snapshot, the facility for rapid image-taking and data storage, was delivered to UKIRT in 1995 as part of the array upgrade, but not in a user-friendly state. Despite attempts (mainly at ROE, effort at the JAC being unavailable) to enhance the quality and reliability of the software, Snapshot was not operating sufficiently smoothly in 1995 to allow general usage, or even to allow the Joint Observatory Seeing Evaluation (JOSE) over-rides allocated by PATT to determine parameters that characterise the atmospheric seeing on Mauna Kea. During 1996 some progress was made, a few JOSE measurements were obtained, and Snapshot was made available on a shared-risk basis for astronomical observing.

The Unix version of the IRCAM data reduction software is now the only version in use at the summit, and the VMS version has been de-commissioned.