SpArc

The data in this archive was gathered on the Kitt Peak National Observatory’s Mayall 4m telescope taken with the Fourier Transform Spectrometer (FTS) during the period from 1975-1995. The FTS produced spectra in the wavelength regime from roughly 0.9 to 5 microns (11,000 to 2000 cm-1), mostly at relatively high spectral resolution. The FTS was developed and maintained at Kitt Peak by Donald Hall, Stephen Ridgway, and Kenneth Hinkle (Hall et al. 1979), in partnership with the solar FTS at the McMath-Pierce Solar Telescope, developed by James Brault1.

During this period (before the development and deployment of infrared arrays), an FTS permitted observations of infrared spectra that could not be obtained any other way. More than 800 targets were observed with the 4-m FTS, many of them multiple times. Targets observed by numerous individual investigators include a variety of normal and peculiar red giants, solar type stars, M dwarfs, variable stars, and early type stars (for telluric line removal) as well as nebulae and galaxies. Observations were limited to a magnitude of K=4 or brighter at R>20,000, although some fainter targets were included at lower resolution. The spectra generally cover a relatively wide wavelength range within the J, H, K, L, or M atmospheric window, and FTS spectrometers provide the advantage of a very clean line profile compared to traditional spectrographs.