ABSTRACT
The potential of night-sky emission lines recorded on every long-exposure astronomical spectrum, for wavelength calibration, is emphasized. A high-resolution atlas, based on spectra obtained with the Keck 10-meter telescope on Mauna Kea and the HIRES high-resolution echelle spectrograph is presented. This atlas shows OH, O2, and a few other night-sky lines, and will make it possible to identify them easily on high-resolution spectra. Accurate wavelengths and references to their sources are given.