Spectroscopy: OH Sky Lines

The Mauna Kea OH Line Emission Spectrum

The following spectra show the OH line emission spectrum in the J, H, K windows at UKIRT. The spectra were taken with CGS4 using the 150 l/mm grating at 3rd order in J, and 2nd order at H & K and the 256 x 256 InSb array (0.61" x 0.61" pixels).

At the bottom of the page are links to more detailed spectra of individual regions of each band. Use these to check the details of the OH emission lines in your wavelength region of interest.

The spectra were wavelength calibrated using this table of OH wavelengths.

• Please be aware that each spectrum is not shown to the same scale. The OH lines in the H window are much stronger than in K, and those in K are stronger than those in the J band.
• The flux units are given as counts, 1 count = 6 electrons, and are per pixel per 100 seconds.
• The spectra are not corrected for atmospheric transmission.
• Wavelengths are in vacuum.
• The solid angle for a 0.61" x 0.61" pixel is 8.7455x10^-12 sr
• The data were obtained by Tom Geballe and Tom Kerr on UT date 1997 19 December
• The CSO taumeter read approximately 0.05 while the data were obtained. This corresponds to an H₂O column of 1mm, a good night on Mauna Kea.

J Band

H Band

K Band

Individual wavelength regions

The spectra below show individual spectral segments covered by the 150 l/mm grating at the listed wavelengths. Approximate airmass is given in brackets. In the J band 3rd order was used (wavelength coverage 0.055um), 2nd order was used for H & K (0.08um).

J Band

H band

K band