The backscatter ultraviolet instrument (BUV) monitored
the spatial distribution of atmospheric ozone by measuring the intensity
of the UV radiation backscattered from the earth's atmosphere. To obtain
this ozone distribution, the BUV subsystem measured direct solar radiation
and backscattered UV radiation from the daytime sun-illuminated atmosphere.
The instrument consisted of a spectrometer (monochromator) and a photometer.
The monochromator measured the intensity of UV radiation backscatter and
reflected radiation from the earth's atmosphere in 12 wavelengths (2555
to 3398 A) in which ozone attenuation occurs. The photometer measured the
reflected UV radiation in a single wavelength span in which attenuation by
ozone does not occur.