Instruments for large telescopes are costly and only likely to become more so as they increase in capability and complexity. Examples of ambitious and expensive instruments being designed and considered for implementation on large telescopes include the wide-field spectroscopic instrument WFMOS (a Gemini / Subaru collaboration) and Next-Generation Adaptive Optics (NGAO) on Keck. Each of these instruments has an estimated cost of $60 million, and HETDEX for the HET is estimated to cost $40 million. The typical cost of a significant, but not as ambitious instrument for an 8-10 meter telescope is of order $10 million. As will be discussed below, ground-based instruments with costs in the $10M-$60M range are substantially out of scale with the NSF programs available to fund such instruments.
5 Telescope System Instrumentation Program
Keck Observatory has participated consistently in the Telescope System Instrumentation Program funded by NSF and managed by NOAO since its inception. TSIP has provided significant funding for two Keck instruments OSIRIS and MOSFIRE, and also for the NGAO preliminary design study. OSIRIS is an integral field spectrometer that provides simultaneous diffraction-limited imaging and R=3,900 spectroscopy behind the Keck II adaptive optics system. MOSFIRE is a near-infrared imaging spectrometer now being assembled and tested that will provide a field of view of 6.8′ in diameter for imaging and allow R = 3,000 spectroscopy with almost full band coverage in Y, J, H or K for 46 slits over a field of view of 6.1′ x 3′. NGAO is a transformational adaptive optics system currently being designed that will deliver unprecedentedly high Strehl, angular resolution, and PSF stability from red-optical to near-infrared wavelengths, through the use of multiple laser guide stars and atmospheric tomography.
In return for TSIP funding, NOAO has gained time on the Keck telescopes to allocate to the broad community (typically 24 nights per year; see Figure 4). Keck TSIP telescope nights have been the most heavily subscribed observing resource offered by the NOAO TAC; note the average oversubscription factor of 5.1 for Keck I and II reported in Table 2 of NOAO’s ALTAIR Committee Report ().
NOAO’s ALTAIR committee which investigated community access to large telescopes reported that “the access to the additional capabilities on the non-federal facilities that is afforded by TSIP and the NASA open access time on Keck is highly valued by the community.”