GEIPAN Case 1979-07-00644 — PRANLES (07) 21.07.1979

Brief

On the night of 21 July 1979, four witnesses at two separate rural residences near Pranles (Ardeche) independently observed an aerial phenomenon stationary at azimuth 288° northwest, more than 2 km distant. The primary witness, a scientific professional with 20 years of expertise in photometry and colorimetry, produced a detailed technical report describing an ovoid yellow-orange source (estimated 3,000–3,600 K) centered by two intensely bright focal points, from which a blue rotating beam (estimated 8,000–10,000 K) swept 360° clockwise at a constant ~25-second interval. The phenomenon lasted approximately 43 minutes before disappearing in a rapid flash-and-recession sequence of 2–3 seconds. GEIPAN's 2019 re-examiner assigned only 30% probability to the sole candidate explanation — a helicopter equipped with a projector — citing perfect immobility, anomalous beam color relative to its source, and a distinctive disappearance mode as incompatible with that hypothesis.

Metadata

Agency

GEIPAN / CNES

Release

2007-03-22

Type

PDF • .pdf

Length

17 pages

Classification

UNCLASSIFIED (GEIPAN public archive; original case classification D — unexplained/strong anomaly)

Programs

GEIPAN, GEPAN, SEPRA

Tags

stationary ovoid, yellow-orange luminous source, blue rotating beam, 360-degree sweep, Pranles Ardeche France, 1979, GEIPAN classification D, nighttime visual, 43-minute duration, flash-and-recession departure, multiple independent witnesses, silent

Key points

• Four witnesses in two independent groups, at separate rural domiciles, observed the same phenomenon simultaneously on the night of 21 July 1979; one group observed continuously for ~43 minutes, the other for ~10 minutes before retiring.p.1
• T1, described as a 20-year director of an internationally recognized scientific service specializing in light and color metrology, produced a formal technical report handed to gendarmerie on 23 July 1979.p.5
• The phenomenon was perfectly stationary at azimuth 288° (northwest), estimated at 100–150 m above the intervening ridgeline and more than 2 km from the observers, observed continuously from 22:45 to 23:28.p.2
• The yellow-orange ovoid source (estimated 3,000–3,600 K) was centered by two permanently immobile, intensely bright focal points estimated at 5,000–6,000 K; the interior of the halo showed animated colored movements.p.3
• A blue rotating beam swept 360° clockwise at a constant ~25-second interval, illuminating mountain terrain for kilometers; its estimated color temperature (8,000–10,000 K) was dramatically different from the yellow-orange source.p.4
• T1 explicitly noted the complete absence of the expected successive-contrast afterimage despite prolonged dark-adapted observation of an intensely bright source — a physiological anomaly he flagged as significant.p.5
• The disappearance followed a three-step rapid sequence: a sudden nearly unbearable luminosity increase, abrupt extinction of the main source, then the remaining point appeared to recede at very high speed and vanished with scintillating flashes within 2–3 seconds.p.5
• Geometric analysis by GEIPAN's re-examiner confirmed the UAP was aerial — the beam did not illuminate the near slope of the first ridge, ruling out any terrain-mounted terrestrial source along azimuth 288°.p.11
• T2, an independent witness at a separate domicile, corroborated the same azimuth, timing, orange-blue color character, and fixed position, confirming the two elements GEIPAN considers most anomalous.p.12
• GEIPAN's only viable hypothesis — helicopter equipped with a high-power projector — was assigned 30% probability ('faible'), with the primary counterarguments being 45 minutes of perfect immobility, anomalous blue beam color, and the flash-and-recession disappearance mode.p.15

Verbatim

• On peut cependant estimer la température de couleur comprise entre ->3000° et 3600° Kelvin, avec une prépondérance spécifique d'ondes longues, -> JAUNE -> JAUNE-ORANGE-> ORANGE, communiquant à l'émission une nuance chaude, jaune-orangée très nette, et très opposable à la lumière froide, bleutée, des étoiles alors observées dans le même contexte.

  p.3

• Ce point donne l'impression de partir en arrière, à très grande vitesse, la lumière perçue décroit extrêmement vite, # 2 à 3 secondes, jette quelques éclats scintillants, disparaît. Le ciel redevient brutalement noir.

  p.5

• Dirigeant depuis 20 ans un service xxx xxx de pointe internationale, habitué comme tel aux analyses les plus rigoureuses et les plus variées dans des domaines scientifiques interdisciplinaires, utilisant la lumière, la couleur et leur METROLOGIE, JE CONSTATE QUE CE PHENOMENE NE PARAIT AUCUNEMENT POUVOIR CORRESPONDRE (NI MEME S'APPROCHER) A UNE EMISSION LUMINEUSE CONNUE, PAR L'INTENSITE MEME DE SA LUMIERE, PAR SA DYNAMIQUE, PAR SES CARACTERES CHROMATIQUES INSOLITES, PAR SON ALTITUDE, DANS UN CONTEXTE DE VISIBILITE PARFAITE ET DE SILENCE ABSOLU, POUR UNE REGION minutieusement étudiée depuis 2 ans, avec TOUTE LA RIGUEUR SCIENTIFIQUE CRITIQUE.

  p.5

• Le 21.07.1979, vers 23 heures, alors que je m'apprêtais à fermer les volets de ma chambre, j'ai aperçu dans le ciel, en direction du lieu-dit "Serres de Pieroulet ", une lueur orange qui devenait bleue par moment. Cette lueur augmentait et diminuait d'intensité. Une lumière bleuâtre éclairait la montagne sur le versant de la commune de CREYSEILLES.

  p.8

Most interesting

• T1's professional specialty was photometry and colorimetry — the precise discipline most relevant to analyzing the phenomenon he observed. His report reads as a formal scientific paper, including attempts at filter-based spectral analysis and physiological control observations.
• The rotating beam's estimated color temperature (8,000–10,000 K, blue-white) was more than twice that of its source (3,000–3,600 K, yellow-orange) — a physically unusual pairing that GEIPAN's re-examiner treated as a primary anomaly marker.
• T1 tested trichromatic selection filters on the emission and found no change in perceived color, which he noted could indicate a discontinuous ('line') spectrum of the kind produced by certain rare gases such as xenon.
• T1 noted that the disappearance coincided — he marked this with a question mark — with his raising a telephoto lens toward the phenomenon, implying possible reactive behavior.
• T1 referenced a prior anomalous daytime phenomenon he had observed at the same location in 1969, which he had formally reported to the general commanding the regional air zone, suggesting a decade-long pattern at this site.
• Despite the observation lasting 43 minutes and the beam illuminating terrain for kilometers, complete acoustic silence was maintained throughout; no sound of any kind was detected.
• T2 and their spouse stopped observing and went to sleep after 10 minutes, while T1 remained engaged for the full duration — the same object produced sharply different perceived strangeness depending on the observer's background.
• GEIPAN's re-examiner noted that gendarmerie investigators failed to press T2 for additional detail, limiting the independent corroboration value of that testimony.