Haute-Provence Observatory The Observatoire de Haute-Provence ( OHP , Haute-Provence Observatory in English ) was established in 1937 as a national facility for French astronomers . Astronomical observations began in 1943 using the 1.20 m telescope , and the first research papers based on observations made at the observatory were published in 1944 . Foreign observers first used the observatory in 1949 , when Geoffrey and Margaret Burbidge visited . OHP is situated in the southeast of France , about 90 km east of Avignon and 100 km north of Marseille . It lies at an altitude of about 650 m , on a plateau near the village of Saint-Michel-l'Observatoire in the Alpes-de-Haute-Provence département at 43.935° N 5.699° E . The site was chosen for an observatory because of its generally very favourable observing conditions . On average , 60% of nights are suitable for astronomical observations , with the best seasons are Summer and Autumn . About 170 nights per year on average are completely cloudless . The seeing is usually around 2 '' but can reach 1 '' or lower on occasion . Seeing degrades severely , sometimes to over 10 '' , when the cold Mistral wind blows from the northwest . This happens on about 45 days per year on average , mostly during winter . Good weather conditions often follow a Mistral . On average , atmospheric absorption at OHP is roughly twice that seen at the European Southern Observatory ( ESO ) at La Silla , Chile . Telescopes The four main telescopes at OHP are all reflecting telescopes with primary mirrors of diameters 1.93 m , 1.52 m , 1.20 m and 0.80 m . The 1.93 m telescope was built by Grubb-Parsons and installed at the site in 1958 . One of the instruments available on the 1.93 m telescope is the high resolution ELODIE spectrograph . Michel Mayor and Didier Queloz discovered the planet orbiting the star 51 Pegasi from observations made using ELODIE on the 1.93 m telescope . The 1.52 m is almost identical to the 1.52 m telescope at the European Southern Observatory in Chile , and has been in use at OHP since 1967 . It is predominantly used for spectroscopic studies , using the high resolution spectrograph Aurélie . The 1.20 m telescope was the first to be installed at the site , and has been in use since 1943 . It was originally installed at the Observatoire de Paris in 1872 . It is now equipped with a direct CCD camera at the f/6 Newton focus and is mainly used for studies of variability of X-ray sources , imaging of galaxies and H II regions and astrometry of faint solar system objects . The 0.80 m was first used during site testing at nearby Forcalquier in 1932 before the construction of the observatory at Forcalquier for site testing in 1932 , and was moved to the observatory site in 1945 . and was later moved to St . Michel in 1945 . The telescope is equipped with CCD cameras allowing high quality observations to be made using it , but unlike the other telescopes on site which have computer-controlled pointing systems , the 0.80 m telescope must still be pointed manually , using setting circles . It is often used by visiting undergraduate astronomy students . Other telescopes at OHP are operated by other organizations , including a 1 m telescope belonging to Geneva Observatory , a 0.5 m telescope operated by the French Space Agency for satellite tracking , and the Berlin Exoplanet Search Telescope , a 0.2 m telescope used to search for exoplanets by observing transits across solar-type stars . Geophysics While primarily an astronomical research facility , the observatory also hosts two geophysics research stations , one studying the mesosphere and thermosphere and the other using lasers to probe the troposphere and stratosphere , studying aerosol and ozone content , using lidar techniques . External link OHP web site ( bilingual ) Categories : Astronomical observatories in France | Asteroid discoverers | Alpes-de-Haute-Provence In other languages : Français | 日本語 43.935 N 5.699 E type : landmark_region : FR-04 