THE UNITED KINGDOM INFRARED TELESCOPE
ANNUAL REPORT
1999

3. Report on Operations

3.1. Summary

• UKIRT's fault rate improved by a full percentage point, with 2.6% of science time lost to faults in 1999 compared to 3.5% in 1998. This is a great achievement by UKIRT staff in a year which saw the full release of UFTI as a common user instrument, the completion of the UKIRT upgrades programme, and considerable changes to computing arrangements at the summit. Weather losses were similar to the previous year, at around the 10% and 20% level in the ``A'' and ``B'' semesters respectively.
• ORAC development continued to installation of the system with UFTI in October, followed quickly by a decision to attempt a ``big bang'' release including retrofitting to the legacy instruments in the summer of 2000.
• Emissivity varied considerably through 1999, and our ability to measure it improved at the same time with reflectometer and photometry giving good additional checks on its value.
• UKIRT's image quality remains high, with many nights delivering 03 seeing. The superlative seeing which characterized the entire month of September 1998 has not yet returned, but half-arcsecond nights remain commonplace, 0.7 arcsecond is poor, and steps are being taken to enable flexible scheduling of programmes with stringent seeing requirements.
• UFTI continues the trend toward smaller pixel sizes driven by the telescope's improved image quality. Some hardware problems, internal to the cryostat, were solved in-house and the instrument was being used with IRPOL by late 1999. This gives UKIRT a unique polarimetry capability on MK.
• ORAC-DR, the in-house part of the ORAC project, was the subject of considerable interest from other observatories and continued its development for UFTI and IRCAM data reduction.
• The MPIA Shack-Hartmann system was implemented by N. Rees. This system enables automatic focussing of the infrared instruments without reference to the infrared image quality, and also permits an independent, quick estimate of the atmospheric seeing.
• A recurring theme of reports filed by visiting observers is that the support afforded by UKIRT staff in 1999 was of the highest quality.