 The main dome of the observatory | |
| Alternative names | Kryoneri Astronomical Station |
|---|---|
| Organization | Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing of theNational Observatory of Athens |
| Observatory code | L10 |
| Location | Mount Kyllini,Greece |
| Coordinates | 37°58′19″N22°37′07″E / 37.97194°N 22.61861°E /37.97194; 22.61861 |
| Altitude | 930 metres (3,050 ft) |
| Established | 1972 |
| Website | https://kryoneri.astro.noa.gr/en/ |
  Location of Kryoneri Observatory | |
 | |
TheKryoneri Observatory (Greek: Αστεροσκοπείο Κρυονερίου), also known as theKryoneri Astronomical Station (Αστρονομικός Σταθμός Κρυονερίου), is anastronomicalobservatory inCorinthia,Greece, operated by theIAASARS research institute of theNational Observatory of Athens. It is home of one of the largest telescopes in Greece, a 1.23 metres (48 in)Cassegrain reflector, which was used for theNELIOTA project ofESA andNOA. The observatory is also housing smaller instruments that are conducting research for IAASARS and are participating in international programmes.
The Kryoneri Observatory was established in 1972 and in 1975 its first telescope was installed, a 123 centimetres (48 in)Cassegrain reflector manufactured byGrubb Parsons, aBritish company based inNewcastle.[1] The telescope was financed by the bequest ofMarinos Korgialenios, a businessman and national benefactor of Greece who had bequested 200,000drachmai to the National Observatory of Athens for the purchase of a largeequatorial telescope in 1916. At that time the director of the Observatory wasDemetrios Eginitis, a personal friend of Korgialenios and on whose request the bequest was given. However, the purchase of the telescope had to be postponed several times due to events like theFirst World War and theGreco-Turkish War. After theSecond World War, Korgialenios' bequest had suffered considerable mutilation and the subsequent distress of the country ledStavros Plakidis, then director of the Οbservatory, to decide that such a purchase could not be made.[2] Finally in 1971, 55 years after Korgialenios bequeathed to the Observatory,Demetrios Kotsakis submitted an application to theGovernment for 12,000,000drachmai. So an essential increase of the bequest was effected permitting to start enquires and discussions with a view to buy a telescope of 100 to 120 centimeters, and 4 years later a telescope was installed in the recently established Kryoneri Observatory.[2] This telescope, which still is the main telescope of the observatory, came to be known as the Korgialenio telescope (Greek: Κοργιαλένειο Τηλεσκόπιο) and the observatory is sometimes referred to as the Korgialenios Astronomical Station of Kryoneri (Κοργιαλένειος Αστρονομικός Σταθμός Κρυονερίου).
In 2016, a major upgrade was conducted to the telescope byDFM Engineering, in order for it to be suitable forNELIOTA project. It included its conversion into a prime focus telescope, the replacement of some mechanical parts, the installation of a new control system, an increase of the automation of the dome and the installation of a new instrument.[3]
The Kryoneri Observatory is located in theCorinthia regional unit of thePeloponnese. It was built onMount Kyllini at an altitude of 930 meters above sea level. The closest settlement isKryoneri and the observatory is named after it.[4]
The Kryoneri Observatory consists of three buildings:
The Korgialenio telescope is one of the largest telescopes in Greece, with only theAristarchos 2.3m Telescope in theChelmos Observatory and the 1.3m Telescope in theSkinakas Observatory being larger in size.[5][needs update] It is the main telescope of the Kryoneri Observatory and it was manufactured and installed byGrubb Parsons in 1975. It is aCassegrain reflector with a 123 centimetres (48 in) parabolicprimary mirror and a 31 centimetres (12 in) hyperbolicsecondary mirror, both of which were created withZerodur. Itsmounting is based on a modifiedtorque-tubeequatorial system. The telescope was converted to a prime focus telescope byDFM Engineering in 2016 and its Prime Focus Instrument (PFI) was installed, which is able to provide the largefield of view, making it suitable for theNELIOTA project.[3] On the back of the Prime Focus Instrument there are two fast-framesCMOS Andor Zyla 5.5 cameras offering the ability to record a target simultaneously in two different wavelength bands. The Instrument can also accommodate another option for imaging, hosting a "direct imaging" Apogee AspenCCD where the light path is directed directly to the prime focus.[6]
A high-power laser transmitter has been installed in the Kryoneri Observatry as part ofNASA'sDeep Space Optical Communications system, and it is the only one located in Europe. In collaboration with the nearbyAristarchos Telescope it achievedcommunication with thePsyche spacecraft in 2025.[7][8]
The observatory is also housing a smaller telescope of the MAWFC Deep Sky Survey, which is located in a role-off building.[9] Next to this building is one of the stations of the Very Wide Field of View (VWFOV) network, which is equipped with a sensor for detecting objects inLow Earth Orbit using OpticalTriangulation. It was manufactured by Cilium Engineering and it was installed in November 2021.[10]
The Near-Earth object Lunar Impacts and Optical TrAnsients (NELIOTA) was a research project funded by theEuropean Space Agency from 2017 to 2023 and it aimed to determine the distribution and frequency of smallnear-earth objects by monitoring lunar impact flashes.[11] For six and a half years the Korgialenio telescope was observing theMoon and detecting flashes on its surface which were caused by near-earth objects colliding with it. Apart from completing its main goal, it also became the largest study on asteroid collisions with the Moon since it was also detecting the size and the mass of the asteroids and the temperature created during the collision.[12]
TheNational Observatory of Athens has signed amemorandum of understanding with thePolish Space Agency for one of the stations of the Very Wide Field of View (VWFOV) network to be located in the Kryoneri Observatory; and for theIAASARS team to contribute to its operations. The station consists of a sensor developed by Cilium Engineering and it is designed to detect objects inLow Earth Orbit using the OpticalTriangulation method. Out of the four such stations, three inPoland and one in Greece, the one at the Kryoneri Observatory was the first to be deployed with its completion occurring on 21 November 2021.[10]
The Manchester-Athens Wide-Field (Narrow-Band) Camera (WAWFC) is a Deep Sky Survey of the extensive line emission regions at highgalactic latitudes.[10] It is a joint project of theNational Observatory of Athens and theJodrell Bank Centre for Astrophysics of theManchester University that aims to conduct a large-area sky survey with the aid of a customized camera and narrow-band filters properly designed for studying extendedinterstellar medium (ISM) structures in the optical emission lines of Ηα, [O III], and Hβ.[13] The WAWFC building at the Kryoneri Observatory was completed on 1 November 2019.[9]
The National Observatory of Athens had signed amemorandum of understanding with theEuroplanet 2024 RI Consortium for the participation of the Kryoneri Observatory in the Europlanet Telescope Network, which was valid until 31 January 2024.[10] As part of the program, the Korgialenio telescope detected lunar impact flashes during thePerseids meteor shower in 2023, using the instruments developed for theNELIOTA project. The results when then combined with the ones from NELIOTA.[14]
The Kryoneri Observatory is one of the observatories chosen by theEuropean Space Operations Center of theEuropean Space Agency for it to observe satellite movements. The goal is to monitor the orbits of satellites for what is known asplanetary security, making sure that the chaotic situation occurring around Earth by the thousands of satellites is under control.[15]
A high-power laser transmitter has been installed in the Kryoneri Observatory as part of theDeep Space Optical Communications system ofNASA. On 7 July 2025, a high-powered laser was fired from the Kryoneri Observatory to thePsyche spacecraft, which then sent back a response to theAristarchos Telescope in the nearbyChelmos Observatory. These two observatories in Greece are the only European ones participating in thislaser communications demonstration, which is to be repeated on July 21, July 28 and August 4.[7][8][15]