Correcting the oh contribution in emission line measurements in the night airglow filter photometry

From the night airglow observations of OH (7-2) and OH (8-3) bands made at Mt. Abu (24.6°N, 72.7°E geographic) we have noted that there is high positive correlation in their intensity variations (Rao and Kulkarni, 1971). Assuming covariation of the other OH band emissions and also their average emission ratios it is possible to estimate the contribution of one band ‘contaminating’ the measurement of line emission made by a filter of moderate width, from the measurement of another band. In the second method an attempt is made to estimate the OH contamination from the measurement through two filters centred on the emission line of airglow.