Abstract: In parts 1 and 2 the authors presented a method to produce a panorama by connecting photographs. In part 3 this method is applied to sky photographs. For this purpose a computer program is presented to calculate the relative position of the two photoprints. An example for this will be introduced, too. Next, a method for estimating the center of a sky photograph and the focal length of the lens of the camera will be presented. This method is based on the celestial coordinates of fixed stars being displayed on the sky photograph. The center and the focal length are important data but often there are gaps in the data when this method is used. The new method offers a more accurate placement of the two photoprints. This method can be applied to measuring the data needed to derive the positions of celestial bodies.
Keywords: sky photograph, celestial coordinate, center of photoprint, focal length
Full text of the article will be available in end of 2002.