PARAY-LE-MONIAL (71) 30.08.2013

For a star-trail photograph at Paray-le-Monial on 30 August 2013, the witness set his camera for long exposures. The next day he noticed a luminous object that seemed to have stayed fixed while the stars formed trails over the stated 5-minute exposure. The opening French also refers to this exposure time as separating shots; the subsequent analysis treats it as a 5-minute exposure. There had been no direct sighting. GEIPAN explains that a point on a long-exposure astronomical photograph more likely records a brief light event than an object stationary throughout all 5 minutes. In fact, it was a short streak, showing movement during part of the exposure. The favoured explanation was sunlight reflected from a satellite. The attached CalSky report showed NOSS 3-3A and 3-3C in the camera's field at the time, culminating at 27° elevation, although the photographed point seemed a little higher. GEIPAN notes that NOSS 3-3C (28541) could appear brighter and more variable than NOSS 3-3A (28537), referring to their Satflare entries. The small black line below the white streak on enlargement was probably JPEG compression ringing. GEIPAN regretted that the images were not captured in RAW format. An attached enlarged Pleiades photograph showed the same artefact as black outlines around star images. The case was classified B: probable photograph of a satellite flare, with uncertainty about the particular satellite responsible.