Konkoly Observatory

Hungarian nobleman Miklós Konkoly-Thege founded his private observatory in 1871 at Hurbanovo, in Northern Hungary, known as Ógyalla in Hungarian at the time.[2] The instrumentation included a 6" refractor, a 10.5" Browning reflector (later replaced with a 10" Merz refractor), a meridian circle, a spectrograph, as well as various meteorological and geomagnetic instruments. Konkoly-Thege, who had no offspring, became increasingly afraid over time that his legacy will perish with his death. As a member of the Hungarian Parliament, he was able to convince the government to take the observatory into state property. In 1899, the Hurbanovo site was renamed to Royal Konkoly-founded Astrophysical Observatory, and operated under the direction of Konkoly-Thege and Radó Kövesligethy, a renowned geophysicist of the time. The main scientific profile of the institute was the photometry of stars, the observation of the Sun, meteor counting, and providing time service for the government. In 1913, an order for a 60 cm (24") telescope was finalized with the German Heyde company, but with the start of World War I, the telescope was never built.

After the end of World War I, Ógyalla became part of the newly formed Czechoslovak Republic. The government transferred the scientific equipment to Budapest before the newly formed border was shut down, and in 1921 allocated a new property in the Buda Hills just west to Budapest to build a new astronomical observatory. The new building, known as the Svábhegy observatory after a nearby hill, was finished by 1924, and the 6" refractor and the re-ordered 60 cm Heyde telescope were set up in new domes by 1928. Scientific work in the observatory focussed on the light variations of pulsating stars, the orbits of binary stars, and searching for asteroids. Measurements were made with photographic plates and wedge photometers.

The observatory survived World War II with minor damages. In late 1944, observations were put on hold, and the optical elements of the telescopes were removed to protect them from aerial bombings. Soviet troops occupied the buildings from December 1944 until February 1945, but the library and the photographic laboratories were spared. Observations were resumed by July 1945.

After the communist takeover of Hungary in 1948, a new network of research institutes, independent from universities, was set up under the Hungarian Academy of Sciences (HAS). The observatory was renamed to the Astronomical Institute of the HAS, but retained the traditional name, Konkoly Observatory, in English correspondences. With the communist isolation of the country, international relations shifted from predominantly German and American to Soviet and Eastern-bloc partnerships. However, the international recognition of then director László Detre kept some connections to the West alive. During one of his visits to the Western bloc, Detre received an RCA 1P21 photomultiplier tube from American astronomer Harlow Shapley to start photometric measurements at the observatory in 1948. He subsequently smuggled in to the country despite the strict trade restrictions at the time. In 1957, after the launch of Sputnik, multiple independent satellite observing and tracking stations were set up in the country at the suggestion of the Soviet Union. The institute provided coordination for these stations, and in 1966, the Baja station merged into the institute.

Relations with the West soon eased and at the 1961 General Assembly of the International Astronomical Union at Berkeley, the institute was tasked with setting up and circulating the Information Bulletin on Variable Stars. The Bulletin was envisaged to be a rapid communications platform between variable star observers, but it later expanded into a peer-reviewed journal for short papers and notes about variable stars.

The institute expanded in the 1960-70s with the foundation and subsequent independence of the Debrecen Heliophysical Observatory and the installation of new telescopes at Piszkéstető Mountain Station. In 1982, the observatories in Debrecen and Budapest were merged back together to form the Research Institute for Astronomy of the HAS. In 1992, the Baja station was separated from the institute and handed over to the county council of Bács-Kiskun.

In 2012, the Hungarian Academy of Sciences reorganized the structure of its institute network:[3] the Astronomical Institute was merged with three other entities (Institutes for Geography, Geochemistry, and Geodesy and Geophysics) to form the Research Center for Astronomy and Earth Sciences. In 2019, the Hungarian government transferred the research institute network of the Academy, including the Research Center for Astronomy and Earth Sciences, to a newly formed entity called Eötvös Loránd Kutatási Hálózat (Eötvös Loránd Research Network).[4]

• 
  The main building of the observatory.
• 
  Telescope domes at Konkoly Observatory in Budapest. From left: the 6", 7" and 24" domes. The latter houses the 60 cm Heyde refractor.

In 1946, a new Solar physics department was initiated under the leadership of Lóránt Dezső. In 1958, the department moved to Debrecen to form a new solar observatory independent of the Astronomical Institute. Observations of the Sun started with two photoheliograph telescopes, one of which was relocated to the top of the water tower at Gyula in 1972. In 1973, a large coronagraph telescope with a 53 cm aperture was set up, but observations were hindered by the cumbersome mechanical setup. Given the low elevation of the observatory of just 124 m above sea level, the coronagraph was only capable to observe the chromosphere of the Sun, not the corona itself.

The main scientific output of the observatory has been the detailed documentation of the photospheric activity of the Sun.[5] The positions, sizes, structures of sunspots and sunspot groups are determined and recorded daily, to provide long-term, homogeneous observations of the Sun. The Debrecen Photoheliographic Data (DPD) database is the direct continuation of the Greenwich Photoheliographic Results that were collected between 1874 and 1976. Originally, analog photographs and CCD images were collected locally, or from partner observatories, but with the advent of reliable space-based observations, the work transitioned to the analysis of images from the SOHO and SDO spacecraft. Further data products include the reanalysis of the Greenwich catalog, and older observations based on Hungarian drawings of the Sun.

In 1982, the observatory merged back into the Konkoly Astronomical Institute, and became a department of it once again. In 2015, the old observatory building in Debrecen was deemed unfeasible to maintain, and was closed down. The coronagraph was disassembled, and offices and personnel were transferred to the ATOMKI institute of the HAS in Debrecen. Given that space-based imagery has superseded the ground-based observations as the input source of the databases, the two photoheliographs were also decommissioned and removed from their mounts at Debrecen and Gyula.

In 1951, the observatory secured funding for a new mapping telescope. The initial order was for a 0.9 m, f/3 Sonnefeld telescope but it was soon modified for a 60/90 com Schmidt telescope. With the light pollution of Budapest steadily increasing, a more remote location was sought for the telescope. After settling for Piszkéstető peak in the Mátra mountains, about 80 km away from the capital, a residence building was constructed in 1960, and the new Schmidt telescope was installed in 1962. The telescope provided a 10°x10° field of view with photographic plates and could be equipped with an objective prism for low-resolution mass spectroscopic observations. The large field-of-view led to numerous supernova and asteroid discoveries at the time.

In 1966, a smaller, 0.5 m Cassegrain telescope with a two-channel photoelectric photometer was installed.

Finally, a 1 m Ritchey-Chrétien-coudé (RCC) telescope was installed in 1974, for high-resolution imaging and photometry of fainter targets. This marked the end of the initial development of Piszkéstető station.

Aerial image of Piszkéstető Mountain Station of the Konkoly Observatory in the Mátra hills.

In the late 1990s, photographic plates and photometers were replaced with CCD cameras on the Schmidt and RCC telescopes. In 2015, an echelle spectrograph with a spectral resolution of R=20,000 was installed on the RCC telescope.

A 40 cm Ritchey-Chrétien telescope was set up in 2010, intended for automated remote observations. The telescope is currently under refurbishment.

The Fly's Eye system, consisting of 19 small cameras to observe the whole sky above 30° altitude simultaneously, was installed in 2016.

A new, automated 0.8 m telescope to track transient events, e.g., supernovae, is expected to be installed in 2018.[6]

Piszkéstető also hosts other instrumentations, including a seismic and gravimetric station of the Institute for Geophysics and Geodesy, and an infrasound detector array.

• 1899–1916 Miklós Konkoly-Thege
• 1916–1936 Antal Tass
• 1936–1938 Károly Móra
• 1938–1943 Károly Lassovszky
• 1943–1974 László Detre
• 1974–1996 Béla Szeidl
• 1997–2009 Lajos Balázs
• 2010–2015 Péter Ábrahám
• 2016–2018 László Kiss

• from 1 January 2019: Róbert Szabó