Atmospheric emission in the 20-micron window from Mauna Kea

This is the authors' abstract. We don't add key points for this paper.

The emission spectrum within the 20-μm window of the atmosphere above Mauna Kea has been measured to a resolution of 0.01 cm -1 with a Michelson interferometer and compared to a single-layer synthetic spectrum in order to test the feasibility of observing fine-structure emission lines from astronomical sources from this site. It is demonstrated that the observed spectrum can be very closely simulated by the inclusion of CO 2 , H 2 O, and N 2 O in the synthetic spectrum, a situation which is presumed to hold for other high, dry observing sites. The present data indicate that large telescopes equipped with high-resolution spectrometers can still be used to advantage in the observation of selected fine-structure lines against the background emission from these sites, particularly when careful background subtraction techniques are used.