With first light for the Gemini North telescope rapidly approaching, KPNO is actively working to fulfill the vision for its new role in forefront Northern Hemisphere astronomy. That vision was articulated in the proposals to NSF for renewal of NOAO facilities and for renewal of the Cooperative Agreement with AURA. It portrays a 21st century observatory that complements and supports the capabilities of Gemini North.
The Gemini North telescope will be optimized for high image quality over a 5'-7' field, with particular emphasis on the near-infrared. Initially, it will offer imaging in the near and mid-IR, long-slit and integral field spectroscopy in the optical and near-IR, as well as multiple object optical spectroscopy . Since Gemini North will take on the role of supporting the community for spectroscopy and limiting near-IR imaging of the faintest objects, the current pattern of use of the Kitt Peak 4-m class and smaller telescopes will clearly change.
The lean, effective Kitt Peak envisioned consists of the Mayall 4-m for optical and near-IR imaging and spectroscopy; the NOAO 40% share of the WIYN telescope for moderate-field high quality imaging and wide-field multi-fiber spectroscopy; and a 2.5-m class telescope for dedicated wide-field optical and near-IR imaging and surveys. Such a suite of telescopes is (barely) consistent with the current level of funding support, and reflects the shift in aperture size by a factor of two with the advent of Gemini.
The Mayall 4-m is likely to support more programs of reconnaissance spectroscopy, while continuing to provide limiting wide-field imaging at the prime focus. The CCD Mosaic imager will be populated with science-grade devices from SITe, and is likely to be available for regular use in that mode no later than semester 1999A. Sam Barden is leading a development program for volume-phase holographic gratings that hold the promise of combining increased efficiency and broad spectral coverage at interesting resolution. With the positive outcome of his NSF-funded development program with KOSI optics company, we plan to optimize a new spectrograph based on this grating technology to replace the aging R-C spectrograph on a 3 to 4 year timescale.
NOAO is collaborating with Richard Elston (Florida) in development of his FLAMINGOS near-IR imager and multi-object spectrograph. The goal is provide cold multi-slit masks that could be changed out on a daily basis. The field of view will be about 10' at the f/7.6 Cassegrain, feeding a 1024 square HgCdTe array. Grisms will allow low-dispersion survey spectroscopy, particularly aimed at efficient redshift surveys for faint galaxies. With sufficient availability of ALADDIN InSb arrays, we will re-populate some channels of the SQIID multi-color imager for simultaneous multi-band imaging. As user demand dictates, we will also provide the ONIS imager/low-dispersion spectrograph, produced by OSU for shared use between KPNO and the MDM 2.4-m with its two-quadrant ALADDIN array and fine pixel sampling of the PSF. The future availability of the workhorses IRIM and CRSP will also be dictated by user demand.
High-dispersion spectroscopy at the 4-m is currently provided by the Cassegrain echelle spectrograph. Since the advent of Keck High-Res, we have seen a reduction in demand and in submitted proposals highly ranked by the TAC for the echelle. At the same time, the coudé spectrograph at the 2.1-m fed by the 0.9-m Coudé Feed telescope provides unique capability for very high dispersion spectroscopy, approaching resolutions of 300,000. To rationalize the workload of our over-committed staff, we must reduce the complexity of mountain operations. The combination of these considerations leads us to a plan to move the Coudé train with the highest dispersion cameras to the large Coudé room of the 4-m. The spectrograph will be fed with a fiber pair and image slicer. Placement of the fiber where it can be fed by insertion of the tertiary will allow an easy switch when the telescope is working at f/15. The completion of that project is dependent on two other efforts discussed below. Until that time, the Coudé Feed remains open for your proposals. We will schedule the programs that are recommended by the TAC to the extent possible. Several of you noticed that the time is not fully subscribed, and that many nights in the semester are marked "closed." Those nights will not be available for programs that could have been reviewed through the normal TAC process. The Director will consider requests for targets of opportunity undergoing unique variable episodes or required to support larger campaigns not known about at the time of the proposal deadline.
We will continue the vigorous program of upgrading the delivered image quality at the 4-m. The dome vents have made a dramatic difference in the uniformity and volume flushing of the dome air. This summer will see the upgrading of the primary mirror support system to one of active control, following the lead of CTIO. Completion of the software interfaces to take and process wavefront data will extend into FY 1999. Further effort will be required that year to improve the refrigeration of the primary mirror bulk for tighter thermal control. The KPNO Users Subcommittee endorsed these measures of improving the overall DIQ as having the highest priority for telescope improvements.
The WIYN Telescope stands as the flagship of performance on Kitt Peak. The WIYN partners are developing a strategy for upgrading the telescope performance and instrument complement. A major step is the production of a tip/tilt imager for use at optical wavelengths. The improvements in Strehl ratio may well be modest, but the ability to compensate for windshake, tracking errors, and small residual thermal non-uniformities should bring about significant improvement in image quality over a finite field of view. The improvements in setup time that are soon to be achieved with the Hydra positioner being fabricated for the Blanco 4-m can then be translated to upgrades of the existing positioner on WIYN. The partnership is actively exploring the implementation of near-IR imaging and fiber-fed spectroscopy. Both the Users Committee and the Observatories Visiting Committee endorse continuing the queue observing experiment, so that we can be prepared as a community to make maximum use of Gemini time through improving efficiencies in the quality of data delivery from WIYN.
The third component of the new observatory is a wide-field imaging telescope. The workshop on Supporting Capabilities for Large Telescopes identified imaging surveys as a critical component for a suite of major observational problems. Spectroscopy on Gemini will go more than 5 magnitudes deeper in the K band than the flux limit of the 2MASS Survey and significantly fainter in the optical than the limits of the Sloan Digital Sky Survey. Focused surveys over limited areas will be essential for isolating samples for further study and spectroscopic follow-up. KPNO is exploring avenues for developing a 2.4-m telescope in partnership with the University of Colorado and the University of Minnesota. The potential consortium is planned to be inclusive, so that further interested partners can join to pursue additional telescopes. NOAO is committed to providing equal access to both hemispheres with such telescopes, and is working with the consortium to develop a partnership for the first telescope on CTIO as well. The Kitt Peak 2.4-m is planned to go on the site of the existing 0.9-m, which enjoys the same site seeing as the WIYN Telescope. The nominal plan calls for a wide-field corrected Cassegrain for optical imaging, and two addressable Nasmyth foci, one for a dedicated wide-field near-IR imager, and one for instruments developed by faculty and students from the university partners. The partners and NOAO are seeking funding for the project. On the most optimistic timescale, the 0.9-m telescope would be closed in semester 2000A; the telescope will be offered to the community, and the dome will be demolished to make way for the new telescope. Until then, we intend to keep the 0.9-m open for your proposals, with the CCD Mosaic Imager or T2KA.
The promise to the community in the renewal proposal was access to an entire 2.5-m class telescope or the equivalent. The plan currently being explored calls for a 50% share for KPNO. If we were limited to that level of access, users would have the Mayall 4-m, 40% of WIYN, and 50% of the 2.4-m, which is below the minimum level accepted by the NSF review and the Users Committee. We will therefore make every effort to keep the 2.1-m telescope in operation for the indefinite future as well. We will not be able to make major improvements to the system, but the telescope will offer the new GoldCam II for optical spectroscopy, and takes the same suite of IR instruments supported on the Mayall 4-m, as well as serving as a testbed for new IR instruments.
In this time of change and budget stringency, it is easy to focus on a sense of loss. KPNO is committed to renewal, to maintenance and upgrade of observing capability, and to providing an integrated suite of Northern Hemisphere facilities including access to Gemini North.
Richard Green