Abstract
In August 1957, the magistrate Charles Boyer, who was President of the Court of Appeal at Brazzaville in Africa and an amateur astronomer, began to photograph the planet Venus systematically, using a violet filter and his own personal telescope, 256-mm in diameter, with an optical window. His aim was to study the positions of the dark, changing markings that had been detected in ultraviolet light by Ross at Mount Wilson in 1924. He was collaborating with Henri Camichel at the Pic-du-Midi Observatory, who was simultaneously observing with a 60-cm reflector. Over 68 days’ observation, Charles Boyer noted a periodicity of 4 days in the appearance of the markings. Alerted by this, Henri Camichel found the same effect on his series of images. Charles Boyer photographically added together the images on plates obtained at daily, 3-day, 4-day, and 5-day intervals (1). The combination of different images cause the markings to disappear. Only superimposition of 4-day images revealed any detail, the result of periodicity in the planet’s appearance.
Publisher
Cambridge University Press (CUP)
Reference11 articles.
1. Irregularities in the 4-day rotation of cloud markings in the shape of a Y in the upper atmosphere of Venus, and their correlation with the slow rotation of the surface;Boyer;C. R. Acad. Sci. Paris,1971
2. Photographic study of the rotation of Venus;Boyer;C. R. Acad. Sci. Paris,1965
3. Etude de la rotation rétrograde, en 4 jours, de la couche extérieure nuageuse de Vénus
4. Determination of the rotation velocity of markings on Venus;Boyer;C. R. Acad. Sci. Paris,1967