A unique photometer capable of measuring line intensities of <0.1% of the bright background continuum (5 × 106/Å) has been developed and successfully commissioned for the measurement of daytime OI 630.0-nm emission from the thermosphere. The photometer employs a low resolution (104) Fabry-Perot etalon, temperature tuned narrowband (3-Å) interference filter, radial chopper, and up/down counting system. The optimum choice of the photometer parameters and a unique method of eliminating the background enabled us to overcome the limitations of the earlier attempts to make measurements on such phenomena as dayglow and has opened up a wide range of uses. However, at present, it is being discussed only in the context of dayglow measurements.
© 1989 Optical Society of America
R. Narayanan, J. N. Desai, N. K. Modi, R. Raghavarao, and R. Sridharan, "Dayglow photometry: a new approach," Appl. Opt. 28, 2138-2142 (1989)