1 - WHT OPERATIONS DURING 02A ----------------------------- 1.7% of the observing time was lost to technical problems, compared with an average of 3% during the preceding 5 years. NAOMI had a further 7 nights commissioning in May and August 2002. Science observations were carried out in June, July and August, mostly in service mode, for 4 programmes allocated time by the TACs, and for 4 additional proposals submitted under the service scheme. One of the latter yielded FWHM 0.15-arcsec images of the fast-moving (up to 5 arcsec/sec) near-earth asteroid 2002 NY40 during its night of closest approach, resulting in a press release and BBC coverage. NAOMI is now routinely delivering images with FWHM ~ 0.2 arcsec in the near-IR. Performance with faint stars has been improved by installing a baffle near the wavefront-sensor pickoff mirror, to reduce the level of sky background on the wavefront sensor. A further 5 nights are required in 2003A to continue characterisation of NAOMI's performance (FWHM, 50%-encircled-energy diameter) as a function of wavelength, guide-star magnitude, radius from guide star and natural seeing. OSCA, NAOMI's coronograph, was successfully commissioned by the UCL team in May 2002. Suppression performance was characterised in Aug 2002. 2 nights are needed in 2003A to test on-sky the new Lyot-stop holder, the gaussian-profile focal-plane masks, and the pre-NAOMI stop. ?? nights are requested in 2002B for further tests of the Rayleigh laser beacon (which will allow moderate AO correction over a wide-angle field), in particular to characterise the Rayleigh wavefronts using simultaneous laser and natural guide stars, and to obtain the first wavefront-corrected images on a science detector. Sheffield's ULTRACAM was successfully commissioned in May 2002. ULTRACAM is a triple-beam CCD camera, imaging a 5-arcmin field with msec exposure times. The WYFFOS long camera will be commissioned in 2003A. The advantages over the current camera are: (1) accommodation of a much larger number of fibres (up to 1000); (2) an external focus permitting change of detector; and (3) higher spectral resolution (up to 9500 with the small fibres and echelle mode). 2 nights are required for the on-sky commissioning. IAC's LIRIS, the Long-slit Intermediate Resolution IR Spectrograph, will be partly commissioned at the WHT Cass focus during 4 nights in Jan 2003. Up to 6 further nights are required in Jun 2003. LIRIS also provides IR imaging, and may in future take over this role from INGRID, which could then be stationed permanently at a focus of NAOMI. Beyond 8000 A, the QE of the CCDs currently in use falls off rapidly with increasing wavelength, and some of the CCDs (particularly the 2k * 4k EEVs) suffer from serious fringing. MIT offers CCDs with nearly doubled QE in the far red, and very little fringing. ING has a share in a foundry run of these CCDs, with the expectation of receiving three. The first science-grade device will be receievd in late 2002 (ING already has an engineering-grade device), and two more at an unspecified later date. These will provide a single-CCD camera for use with OASIS and on ISIS red arm, and a 2-CCD mosaic use with the WYFFOS long camera and for prime-focus imaging. To provide a CCD for each of OASIS and ISIS red arm, and to spread the risk, ING has obtained a CCD with similar expected performance from Marconi, and this is now the default detector on ISIS red arm. The current autoguider systems (Dutch controllers) are becoming unmaintainable, and they will soon be replaced with ultradas-based systems using Marconi CCD47-20 1k*1k CCDs. They may also replace the Cass and NAOMI acquisition cameras, and provide a 3.6-arcmin imager for WHT aux port (a wider field is needed at aux port if the prime-focus imager is ever decommissioned). A prototype camera has been completed and two fully-working cameras should be complete by Dec 2002. The software will be ready by Apr 2003. The reflectivity of the primary mirror has been maintained since the last aluminising in June 2000 by regular snow-cleaning, but has now declined to 82%. ING plans to wash the mirror in situ on Oct 2002 (using seals to prevent water reaching other parts of the telescope). NAOMI remains in GHRIL until ~ Nov 2002, when it will be moved to the new AO enclosure, GRACE, on the other Nasmyth platform, formerly occupied by UES. After NAOMI's move to GRACE, the GHRIL optical bench will continue to be used for INTEGRAL and visiting instruments e.g. ESA's S-CAM. All but 2 of the 20 user feedbacks for 02A rated their runs 'good' or 'excellent'. 2 rated performance 'sufficient', one because there was no quick-look-reduction software available for ISIS, one because of a major technical problem with UES. 2 - TIME-LOSS STATISTICS FOR 02A -------------------------------- 25 faults, 20 hours lost, mean 47 minutes per fault. The only fault causing loss of >= 3 hours was a failure of a power-supply unit in the PF camera, due to overheating after an air filter was blocked by calima (Sahara dust). 3 hours were lost. 3 - STANDDOWN AND D-NIGHT BID FOR 2003A --------------------------------------- Standdown (commissioning work): nights NAOMI 5 (second half) OSCA 2 (second half) OASIS 4? (Jun?) Rayliegh laser beacon 2.5 (end of semester) WYFFOS long camera 2 (first half) LIRIS 6 (Jun) -- 21 D-nights: Telescope quality control 1 (optical tests, pointing tests) Instrument quality control 3 Instrument setups after changes 1 (including 0.2 nights dark time) -- 5 -- Total 2003A commissioning + D 26 The nights bid for are all bright, apart from 0.2 nights required for setup of the PF imaging camera (usually ~ 2 dark hours at the start of a 'grey' night) and perhaps 0.5 of the NAOMI nights (test of the wavefront sensor with lower sky background). 4 - STANDDOWN AND D-NIGHTS USED IN 02A -------------------------------------- 18.6 nights used = standdown (8.3) + discretionary (5.5) work + associated 4.8 nights bad weather and technical problems (see table below). I.e. the totals, including bad weather and technical problems, are 11.2 nights standdown, 7.4 discretionary = 18.6 in all. 5 - ACTUAL USE OF S/D/STANDDOWN IN 02A -------------------------------------- Service 15.0 Tel. quality control 0.8 Instr. quality control 4.7 Commissioning 8.3 (5.4 for NAOMI, 2.1 OSCA, 0.8 LGS tests) Aluminising 0.0 Bad weather 9.7 Technical problems 0.5 ---- 39.0 (= 18.6 in (4) above + 15.0 service + 5.4 bad weather and technical problems associated with service) 6 - WEATHER AND TECHNICAL DOWNTIME in 02A ----------------------------------------- The last two columns below give for each month the % of observing hours lost to bad weather and technical problems respectively. S/D, commissioning and own-instrument nights are excluded from these statistics. Mon Yr weat tech % % 2 02 34.2 0.5 3 02 21.7 1.9 4 02 51.5 0.0 5 02 36.4 3.6 6 02 4.6 2.6 7 02 3.2 2.1 --- Mean 1.7 (weighted by number of nights each month which satisfy the above criterion) 36% of the observing time Jul 2001 - Jun 2002 was lost to bad weather, the worst such figure for 12 years (but the best, 15%, was for Jul 2000 - Jun 2001). Chris Benn 2002 Sep 1