The Gianini camera - A short-focal-length instrument for the precise determination of thermospheric winds

The use of the short-focal-length Gianini camera in the determination of artificial cloud altitudes and thermospheric wind speeds and directions during the NO-II gas release experiment is discussed. Two Gianini cameras equiped with a 77-mm focal length objective lens opened to F/D equals 0.87 were mounted equatorially to fixed frames at two different locations in order to triangulate on the chemiluminescence induced by the reaction of the injected nitric oxide with thermospheric oxygen between 80 and 150 km. The photographic plates obtained were reduced to obtain the altitudes of the artificial clouds as a function of time and the wind velocities at various altitudes. Extremely accurate values of cloud height (within 40 m) and wind speed (within 1 m/sec) have been obtained which indicate the high quality of Gianini camera triangulations.