Dick Joyce
Wide-field imaging—both in the optical and infrared—is a long-term, key element in the research capability of Kitt Peak National Observatory. We have initiated a concept study of the next generation IR imager to complement that in the optical provided by `Mosaic.' Up-to-date information on the NOAO Extremely Wide-Field IR Imager (NEWFIRM) is available on the NEWFIRM web page, which can be reached from the NOAO Home Page, http://www.noao.edu.
The development of wide-field imaging has been a consistent component in the KPNO long-range instrumentation plan. The need for wide-field IR imaging capability was highlighted in the USGP Workshop on Supporting Capabilities for Large Telescopes, in which it was identified as a critical element in a large number of potential scientific programs to complement observations on 8-10 meter class telescopes. This capability is also crucial for limited survey programs to a much greater depth than provided by surveys such as 2MASS and for ground-based support of space missions such as Chandra and SIRTF.
Based on the results of the Supporting Capabilities Workshop and through internal discussions, we have formulated the following baseline specifications for NEWFIRM:
The first two requirements suggest a 4K×4K detector format. IR detectors in this format do not yet exist, nor are they envisioned for the near future. A monolithic all-transmissive instrument of this size would require optical elements that may be unobtainable. Our initial approach is to investigate an open mosaic of four 15' FOV imagers, which keeps the optics to potentially feasible dimensions and avoids the issue of generating a close mosaic of IR arrays.
Our goal is to complete the conceptual study of the baseline configuration during FY 2000. Additional features such as grism spectroscopy, performance at longer wavelengths, and use on the KPNO 2.1-m telescope will be evaluated as well. Such additions will be weighed against the additional cost and possible compromise of the baseline specifications outlined above. We will post status updates on the WWW as the opto-mechanical study progresses.