Night-sky high-resolution spectral atlas of OH emission lines for echelle spectrograph wavelength calibration .2.

The potential of night-sky emission lines recorded on every long-exposure astronomical spectrum, for wavelength calibration, is reemphasized. The previously published high-resolution atlas, based on spectra obtained with the Keek 10-m telescope on Mauna Kea and the HIRES high-resolution echelle spectrograph, is extended from 9000 to 10,600 Angstrom, the present effective long-wavelength limit for reasonable exposure times with current CCDs. The extension of the atlas shows many OH night-sky lines, and makes it possible to identify them easily on high-resolution spectra. Accurate wavelengths and references to their sources are given. Measured intensity ratios for the resolved, well-measured lambda-type doublets are presented, and the probable errors in the listed wavelengths of the unresolved doublets, based on them, are discussed. Observations and identifications of a number of lines of weak satellite or intecombination bands of OH in the night-sky spectrum are discussed, and the ''not proven'' result of a search for OH lines in the (10-5) and(10-4) bands is mentioned.