Noise EquivalentPower of Background Limited

With the advent of large submillimeter telescopes at high, dry sites, the atmospheric background noise in a moderate bandwidth can be low enough to challenge the ability of instrument designers to produce su#ciently low noise bolometers to be background limited. We compare the predictions for the noise power of a bolometer observing through an emissive atmosphere, considering the e#ect of atmospheric absorption, telescope optical e#ciency, and detector optical e#ciency, with measurements through the atmosphere over Mauna Kea