Jay Elias, Richard Elston, and Richard Green
FLAMINGOS is coming to Kitt Peak. No, this is not a statement about bird life--with bad grammar--but rather an announcement of the possible availability of the University of Florida Wide-Field IR Imager/Spectrometer in Semester 2001A. The availability of FLAMINGOS will be defined after the first engineering run in late August. Information necessary to submit an observing proposal to use this instrument will be available on the NOAO Web page no later than September 6th.
FLAMINGOS is a wide-field IR imager and multislit spectrometer designed and built by Richard Elston (Florida), with some collaboration and support from NOAO. The imaging mode is provided by a fairly conventional optical train, consisting of a refractive collimator, filters, cold stop, and a camera which images the focal plane onto a 2K x 2K HgCdTe detector. The instrument can be used on both the 2.1-m and 4-m telescopes; pixel scale and field of view values for each telescope are summarized below:
|Field of View (arcmin)||10x10||20x20|
J, H, and Ks filters will be available for imaging. Because the filters are located in a fast beam, narrow-band filters, which will not work very well over the full field, will not be provided.
The cold stops are on a wheel, so that an optimized cold stop is available for each telescope. The image quality of the optics (as designed and toleranced) is well matched to typical image quality on the 4-m, and is about 2 pixels FHWM over most of the field (a little worse at the corners). Imaging on the 2.1-m will mostly not be seeing-limited.
The spectroscopic mode is provided by a cold slit mask placed at the telescope focal plane, which is inside the dewar, and by a grism placed after the cold stop. The slit masks are mounted in a wheel in a separate "sub-dewar" within the instrument. The sub-dewar can be warmed up and cooled down quickly, allowing the masks to be changed during the day. The wheel holds several slit masks (enough for a reasonable night's program), in addition to permanently mounted long slits.
The highest resolution available is R~3000, which is sufficient to cover most of an atmospheric "window" with the slit at the center of the focal plane. Lower resolution modes will provide full coverage even for off-center slit locations. A complete listing of the resolution/wavelength combinations that will be provided will be included in the Web posting.
Interested readers will have noted that no information on performance is given above. This is because FLAMINGOS has not yet been tested on the telescope. The first engineering run will take place August 21-23 on the 2.1-m telescope. This run will be with an engineering-grade array, which appears to be almost science grade. Based on the success of the engineering run and the performance of the instrument, we--KPNO and Florida, jointly--will make a decision regarding availability of the instrument. This information will be available on the NOAO Web site no later than September 6. Information on performance sufficient to allow proposal writing will also be provided.
Note that if the instrument is offered, spectroscopic modes may initially be unavailable on one or both telescopes (in particular, the multi-slit mode). Part of the engineering run will be devoted to establishing the procedures needed to produce useful slit masks, including mapping celestial coordinates to focal plane coordinates to detector (pixel) coordinates.
Rough estimates of imaging performance suggest that FLAMINGOS' sensitivity for individual targets will be slightly worse than SQIID. Because of its larger format array, FLAMINGOS will be the preferred instrument for mapping large areas. For smaller areas, such as individual targets, SQIID would likely be the better choice. A better idea of the trade-offs will be available once the engineering run has been completed.
The current thinking is that FLAMINGOS will be shared between Kitt Peak and Gemini South. The tentative agreement is that the instrument will spend six months per year at each site, with a rotation schedule based on access to key regions of the sky. FLAMINGOS will be available at Kitt Peak typically from mid-December through late May. That plan allows access to M31 and companions (for first half-nights), Orion and other star formation regions in the Northern Galactic plane, and the North Galactic Polar Cap. We will therefore solicit proposals each semester; the half-year cycle places about one-third of the time in the B semester and about two-thirds of the time in the A semester.