ALBI (81) 13.04.2015

On 13 April 2015 from 22:10 to 23:30, a witness in Albi (81) observed 2 colored lights in the sky, first with the naked eye and then through binoculars. GEIPAN considers a sighting lasting over 1 hour of multicolored lights moving slowly at the rate associated with Earth's rotation, 15° per hour, typical of celestial objects. The reported directions are imprecise but appear to indicate Procyon and Capella, although these are fainter than Sirius and especially Venus and Jupiter. The source refers to Stellarium sky charts for Albi at 22:10 and 23:10. The unusual features were the changing colors and a shape resembling a sea urchin's shell. Météociel records showed a seasonally high temperature of 27°C. GEIPAN explains that large temperature differences create atmospheric turbulence and strong scintillation, particularly noticeable through binoculars, giving the objects this appearance. It notes that similar scintillation can occur in strong winds, especially warm ones. The witness used 10×25 hiking binoculars, with high 10-fold magnification but small 25 mm apertures. GEIPAN describes these as poorly suited to astronomy and suggests lower magnification of 7× or 8× with larger 50 mm apertures for that purpose. It considers that the binoculars could introduce shape and color aberrations under those conditions and that high magnification makes a steady handheld view very difficult. GEIPAN classifies the case as B: probable observation of celestial objects. A more precise account locating the objects relative to one another would have allowed more exact identification.