CHAVILLE (92) 13.07.2023

On 13 July 2023 at about 04:00, a witness at home in Chaville (92) saw highly organized movements of light. Initially, aligned streaks formed a crown-like shape; these quickly changed into what looked like a whirl of light and then a doughnut shape. This lasted several minutes and ended as a small halo. Only 1 account was collected. GEIPAN considers the supplied photographs consistent with light patches cast onto a low cloud layer by single-beam searchlights, called skyroses. The lights were white to bluish and translucent, with shapes changing between a crown, a line and a doughnut. The witness also reported no sound. GEIPAN explains that such searchlights generally reach more than 10 km. They can be operated automatically or manually and can produce fixed or moving beams, independently or together, in various shapes; the source refers to the JM Sky Tracers website. The cessation of movement, leaving a small halo, could represent a pause to adjust the equipment or the end of a display before switch-off. Weather research found that between 04:00 and 05:00 that day the lowest cloud layer was at 1, 800–2, 300 m, with very good visibility of about 43 km. The source cites weather information for Villacoublay (78), approximately 4 km from Chaville. GEIPAN considers these favorable conditions for light patches to appear on cloud bases and be visible from far away. There may have been festivities near Chaville ahead of 14 July, or equipment tests in preparation for that date. The case is classified as A: very probable observation of light patches on clouds from ground-based single-beam searchlights.