An account in Ni�vre, France

On May 24, 2017, after an evening spent with a group of astronomers observing Jupiter, two witnesses are intrigued by the particular SSE-ENE movement of a very bright point in the sky that moves away and disappears. The witnesses most likely observed the passage of the International Space Station (ISS). The latter is found in the observed directions at the beginning (SSE high in the sky) as well as at the end of the observation (ENE at the horizon). The time given at the end of the observation, 11:45 PM, is off by 8 minutes (end of ISS passage at 11:37 PM), and this discrepancy probably results from a glance at the watch later than the end of the observation and/or a fast watch. Given the intensity of the ISS in the sky (much brighter than any other star) and also more mobile, it is not possible that the witnesses, who came to look at a starry and cloudless sky, did not observe it. The description apparently deviates from a satellite movement in the sky, because a curved trajectory is mentioned. But the description reflects the classic witness error of interpreting a change in light intensity as a radial approach or recession (that is, in the direction of the witness) of the UAP, so that the curvature of the trajectory is not seen in the sky (in rapid evolution of azimuth and altitude) but imagined in the direction of the witness. The expressions clearly reflect this phenomenon: - Witness 1: "it was descending toward us while growing larger," "the ball was moving away very fast toward the north/northeast, rising high in the sky until it became the size of a star, then a small bright point barely discernible, then nothing." - Witness 2: "a luminous and moving object heading toward us," "diving arrival," "it moves away straight ahead of us without going down or up until it disappears." The trajectory reconstruction drawing provided by witness 2 (see questionnaire) shows a UAP coming from the ESE and heading straight toward the witnesses, then turning and heading straight back toward the ENE. A witness cannot detect a radial evolution of an unknown object; they can only interpret it, often incorrectly, based on the concurrent evolution of its size or brightness. Here the brightness of the ISS could have increased very strongly toward its passage at maximum brightness in the East-Southeast position and high in the sky, thus creating the "diving phase of the observation," then decreased in intensity, probably more slowly than during its increase. Consequently, GEIPAN classifies the case as A: observation of the International Space Station (ISS).