title: Waves in the OH emissive layer: photogrammetry and topography.
abstract: The waves in the OH emissive layer, which appear on photographs of the sky in the near IR taken with large aperture cameras, are distorted by atmospheric refraction and by a perspective effect. Two methods have been developed to allow restitution of the topography of the waves in a simple way. In the first method a grid is computed, which is superimposed on an enlargement of the original 24 x 36-mm negative frame. In the second method the image is projected on an aspherical surface that is tilted with respect to the enlarger beam. The topography of a wave display, photographed from the Pic du Midi Observatory during the night of 19-20 November 1976, is obtained using both methods. The photometric aspect of the photographs may be interpreted under the simple assumption that the emissive layer has a constant thickness and is ruffled like the wavy surface of the sea.
authors.forename: M
authors.initials: M
authors.lastname: Hersé
authors.forename: G
authors.initials: G
authors.lastname: Moreels
authors.forename: J
authors.initials: J
authors.lastname: Clairemidi