Tom Barnes and Caty Pilachowski
Beginning with the 2000B call for proposals, observers may request time on the 9.2-m effective aperture Hobby-Eberly Telescope (HET) at McDonald Observatory, under an agreement with the National Science Foundation. The HET is a unique, queue-scheduled, segmented-primary telescope optimized for spectroscopic observations. Access to HET through the Public Access Program will begin in June 2000. Proposals should be submitted through NOAO using the standard NOAO proposal form. Proposals will be reviewed by the NOAO TAC, and those approved will be forwarded to the HET for queue-scheduling. For further details concerning the use of HET for observations and the preparation of observing proposals, see NOAO's mirror site for HET information at http://www.noao.edu/gateway/HET/, and articles in the December issue of the NOAO Newsletter. All observations will be performed in a queue-scheduled mode by HET observers.
The 9.2-m Hobby-Eberly Telescope is in routine science operation two weeks per month. The other two weeks are devoted to instrument commissioning and to engineering improvements to the telescope. This schedule will continue into Fall 2000. A month of shutdown is possible during Summer 2000, with the decision to be taken later. Performance of the HET was described in the December 1999 NOAO Newsletter and has improved somewhat since then. Electro-mechanical performance is excellent; optical performance of the 91-segment primary-mirror array in the 2000B semester is likely to be in the 2.0"-2.5" range (encircled energy = 50% averaged over a 30-minute integration). Seventy percent of the clear, nighttime hours are used for science, with more than half of those hours being integration time. The fractional integration time is steadily improving as we gain experience with this unique telescope. The remaining 30% of the clear, nighttime is used for realignment of the primary mirror array (20%), lost to problems (8%), and `other' (2%). The latter two categories are expected to decrease by Summer 2000; the realignment time will effectively go to zero upon installation of the edge sensor system on the primary mirror array in Spring 2001.
Instrumentation available to researchers on the HET in the 2000B semester will be the Marcario Low Resolution Spectrometer (LRS) and the High Resolution Spectrometer (HRS). These are described in the December 1999 NOAO Newsletter and at http://www.noao.edu/gateway/het. The LRS is a grism spectrometer with imaging and long-sit modes in operation now. The field of view is 4´ in diameter. The two grisms provide resolving powers of 600 and 1300 in wavelength regions 410-1000 nm and 430-740 nm, respectively. The LRS has achieved 1.6" images on the HET, although imaging in the 2.0"-2.5" range is more typical at this time. Researchers planning to use the LRS are asked to consult current performance measures documented at http://www.noao.edu/gateway/het.
The HRS is under construction, with commissioning expected to begin in late April 2000. HRS is a fiber-fed spectrometer with resolving powers of 30,000, 60,000, and 120,000 by means of three slit widths. Spectral coverage is 420-1100 nm. Projected performance characteristics of the HRS are available at http://www.noao.edu/gateway/het and will be up-dated as commissioning proceeds.