Logo of the National Observatory of Athens | |||||||||||||||||||||||||
| Motto | Servare Intaminatum | ||||||||||||||||||||||||
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| Established | 1842 (1842) | ||||||||||||||||||||||||
| Research type | Basic,Applied | ||||||||||||||||||||||||
Field of research | |||||||||||||||||||||||||
| Director | Spyros Basilakos | ||||||||||||||||||||||||
| Location | Athens,Greece 37°58′24.2″N23°43′5.6″E / 37.973389°N 23.718222°E /37.973389; 23.718222 | ||||||||||||||||||||||||
| Website | http://www.noa.gr | ||||||||||||||||||||||||
Observatory
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TheNational Observatory of Athens (NOA;Greek:Εθνικό Αστεροσκοπείο Αθηνών) is aresearch institute inAthens,Greece. Founded in 1842, it is the oldestresearch foundation in Greece. The Observatory was the first scientific research institute built after Greece became independent in 1829, and one of the oldest research institutes inSouthern Europe. It was built around the same period as theUnited States Naval Observatory.[1][2]
The world-renowned Greek-Austrian astronomerGeorgios Konstantinos Vouris lobbied to create the National Observatory of Athens in the newly founded state. He persuaded wealthy Greek-Austrian bankerGeorgios Sinas to pay for the new massive observatory. The Austrian-bornGreek King found out the news and awarded Georgios Sinas's son theOrder of the Redeemer. The King also selected the architects for the building underGeorgios Konstantinos Vouris's supervision, which wereEduard Schaubert andTheophil Hansen.[3][4][5]
The Athens observatory since its inception aided astronomers to conduct research in the field starting fromGeorgios Konstantinos Vouris's catalog for the complete determination of 1000 stars observed from Greece relative to the position of the Athens observatory. The second directorIoannis Papadakis used the facility to observe the Moons of Jupiter andJohann Friedrich Julius Schmidt German-born Greek astronomer conducted countless observations and created a Moon map of the lunar surface from the Athens observatory.[6]
After Schmidt,Demetrios Kokkidis briefly directed the observatory and expanded the existing weather stations adding new ones inCorfu,Zakynthos, andLarissa.[7] By the early 1900s, AstronomerDemetrios Eginitis observed the rare phenomenon known asHalley's Comet from the Athens observatory and wrote about it in his article entitledSur la Comète de Halley.[8] By the middle of the 20th century,Stavros Plakidis continued the legacy of Greek astronomy at the observatory writing countless research papers and continuing his lifelong research on variable stars.[9]
Eginitis and Plakidis allowed a young twenty-two-year-old astronomer namedJean Focas to assist them at the observatory. The young astronomer had no education in the field. After many years at the Athens observatory, later in life, he acquired aPh.D. in the field of astronomy in Paris, and theFocas crater on the Moon and theFocas crater on Mars are named after him for his extraordinary contribution to the field.[10]
Currently, the National Observatory of Athens operates in four distinct locations:
Greek-Austrian astronomerGeorgios Konstantinos Vouris studied astronomy at theVienna Observatory under the supervision ofJoseph Johann von Littrow. Vouris eventually moved to Greece, becoming a professor at the newly foundedUniversity of Athens and he wanted to build an observatory in the country. Around 1840, he lobbied Austrian banker BaronGeorgios Sinas, the Greekambassador inVienna, with the help of the Austrian ambassador in AthensProkesch-Osten. Sinas expressed his intention to make a donation for scientific development in Greece and the Athens Observatory was founded a few years later with Vouris as its first director. Vouris was also involved in the construction of its first building and chose the instruments for the new observatory.[11]
The first building, known asSinas building, was based on a project presented byEduard Schaubert and designed by the Danish architectTheophil Hansen, being the first building erected by the world-renowned architect. The cross-likeneoclassic building has its sides oriented toward the four directions of the horizon. There is a small dome for a telescope in the center of the construction. The building was completed in 1846. Two years after theUnited States Naval Observatory was completed.[12]
The Observatory of Athens foundation ceremony was on June 26, 1842, the day of a Solar Eclipse, and it was a magnificent official event with theKing of Greece, members of the Government, and the Greek Church being all present. A large crowd of people filled up the vicinity of the location selected for the Observatory, a location on the hill of Nymphs atThiseio, facing theAcropolis. Following the panegyric speech by professorGeorgios K. Vouris, the foundation stone was set under musical sounds and cannonade by a Danish frigate anchored at theport of Piraeus.[13]
Vouris was responsible for purchasing and selecting the correct instruments for the newly founded Observatory. He chose a 7.5-inch dialyterefracting telescope (19-cm aperture , 190cm focal length, f/10) made bySimon Plössl of Vienna, Austria. The second telescope was made by Christoph Starke of the Imperial Polytechnical University, Vienna. The device was ameridional telescope 3.7" large (94mm, f/15, diameter 1m). He also purchased a timer and two pendulums along with five small telescopes and a complete line of meteorological equipment. They were some of the most advanced scientific instruments at that time.[14]
The observatory was fully operational and Vouris was the first director. He conducted scientific work in the field of astrophysics, astronomy, and geodesy, publishing articles periodically inAstronomische Nachrichten. He became internationally renowned in the field of astronomy and created a catalog for the complete determination of 1000 stars peculiar to Greece and the position of the Athens Observatory while also determining the geographic coordinates of the Observatory, which formed the basis for the mapping of Greece. Vouris did significant research on the movement ofSirius,Neptune, andMars.[15] He made specific observations of Mars with the Athens Meridian Circle and his research was used by American astronomerJames Melville Gilliss.[16]
In 1855, Vouris became ill and moved back to retire in Vienna, where he died on January 2, 1860. Prof.Ioannis Papadakis, full Professor of Mathematics, since August 17, 1854, at theUniversity of Athens was chosen as an interim Director. In December 1858 the nomination for the new permanent director took place, on December 4Johann Friedrich Julius Schmidt was nominated, and on December 16 Julius Schmidt became the new director of Athens Observatory.[17][13]
Utilizing the Sina's family donation,Johann Friedrich Julius Schmidt repaired and maintained the instruments. He started to observe the Sun, Moon, planets, comets and variable stars. He enriched the Observatory's library with many scientific books and journals. Some of them were donated by other Europeanobservatories. Schmidt also started editing thePublications of the Observatory of Athens.[18]
During the 25 years of his work at the Athens Observatory, he performed more than 70,000 observations of variable stars and discovered several periodic variables and two Novae stars. Most of the results were published in the journalAstronomische Nachrichten.[6]
For many years, J. Schmidt studied the planetsMars andJupiter and drew the changes on their surfaces. He observed the bright comet of 1860 and two years later discovered a comet,C/1862 N1 (Schmidt). The clear sky allowed him to make thousands of observations of meteors. He also had the opportunity to observe a number of solar eclipses of the Moon.[19] On 19 January 1865, while he was inspecting the Cape catalogue nebulae he discovered five galaxies:NGC 1381,NGC 1382,NGC 1386,NGC 1389 andNGC 1428, all of which are members of theFornax Cluster.[20][21]
TheTopographical Chart of the Moon (Chapitre der Gebirge des Mondes) published inBerlin, is his main work. In an area of two meters diameter, consisting of 25 parts and representing the visible surface of theMoon, there are about 30,000 craters drawn as observed with the 7.5 inch Plössl telescope. He conducted a significant study of the craterLinne showing apparent morphological changes.[22]
Julius Schmidt reorganized the meteorological service of the Observatory of Athens. He performed meteorological observations in many places in Greece and regularly sent data to theObservatory of Paris. These results were presented in his workBeiträge zur physikalischen Geographie von Griechenland (1864).[23]
Schmidt also showed a significant interest in the field ofseismology. With the help of volunteers, he recorded more than 3,000 earthquakes and published his work entitledStudien über Erdbeben (1875). He observed theSantorini volcano eruption in 1866 and published the study and three other studies on the volcanos (Etna,Vesuvius,Stromboli) in 1874.[24] Julius Schmidt traveled to the ancient city ofTroy and performed geographical and archeological studies.[18]
Demetrios Kokkidis undertook the Direction of the Observatory of Athens in 1884. Because of the financial situation of the Observatory (the funds of the Sinas family donation were already exhausted) and the fund from the Sinas family that paid Schmidt's salary was no longer paying the Observatory directory. Regrettably, Kokkidis volunteered his time for no payment but had very limited possibilities for administrative and scientific activity. The astronomer was able towrite articles in the field of astronomy and expand the existing weather stations adding ones inCorfu,Zakynthos, andLarissa. He continued regular meridian circle observations for the purpose of recording time and observedsolar spots.[7]
TheGreek Parliament passed a special law on June 19, 1890, making the Athens Observatory a government research facility. The name was changed toNational Observatory of Athens abbreviated NOA. Because of the special law,Demetrios Eginitis was appointed Director of the NOA. In addition to the Astronomical Institute, two others Institutes were created, the Meteorological and the Seismological Institutes.[25]
Eginitis worked diligently to find funding for the new institute. He received credit from theUniversity and restored the observatory building and updated the equipment. Because of the economic situation in Greece, government aid was very limited but Eginitis organized a national committee that collected considerable funding and donations from the local Greek community.[26]
TheThiseio site of the Observatory was expanded, a neighboring area was purchased and three new buildings were erected with the newly raised funding. State-of-the-art new instruments were ordered and installed at NOA, a 16 cm meridian circle and a 40 cm refractor. Another telescope, a 20 cm reflector was donated by K. Ionidis.[27][28]
Eginitis reorganized the meteorological network, adding about a hundred new stations and creating a seismological service. He also organized the addition of a catalog entitledAnnales de l'Observatoire National d’Athènes.[29]
Eginitis played a significant role in the political and academic life in Greece. He was Minister of Education in 1917 and in 1926. Eginitis introduced theEastern European Time Zone in Greece and replaced theJulian calendar with theGregorian calendar making it the country's new standard. He founded theAcademy of Athens and organized theUniversity of Thessaloniki.[30]

Stavros Plakidis attended the School of Physics and Mathematics at theUniversity of Athens and graduated in 1915 one of his professors included Demetrios Eginitis. Plakidis became an assistant at the Observatory in 1915. After over a decade at the institution, he was promoted to assistant astronomer in 1927. One year later in 1928 with the recommendation of Professor Eginitis Plakidis continued his studies for two years in Greenwich, Cambridge, Paris, Strasbourg, and Heidelberg.[31]
While in Cambridge he collaborated with professor SirArthur Eddington on a paper in 1929 entitledIrregularities of the Period of Long-Period Variable Stars.[32] He became well known for his work onlong-period variable stars and frequently collaborated with professor Sir Arthur Eddington throughout his life. Plakidis became a well-known astronomer and continued his work in the field of observational astrophysics. He published many papers in famous astronomical journals. In 1931, he was proclaimed Doctor of Mathematics and was nominated regular astronomer of NOA. Around this period,Jean Focas became an assistant at the observatory after Plakidis' recommendation.[10][9]
In 1935, after the death of Eginitis, Plakidis was elected Professor at theUniversity of Athens and at the same time was nominated Supervisor of the Astronomical Department of NOA. In two years the NOA changed two Directors, firstly professor Nikolaos Kritikos was nominated, thenElias Mariolopoulos. In 1937, the Director of NOA Georgios Chors was nominated.[31]

Stavros Plakidis made many efforts to move the observations far from the city center. In 1936, he founded thePenteli Astronomical Station inPenteli, began to function in 1937 but because ofWorld War II, the equipment including three refractors, Bardou 6 in., Secretan 4.4 in., Zeiss 3 in., the Watts theodolite, the photo-visual refractor, Zeiss 4.4 in. with solar and lunar cameras, Herschel and Colzi prisms, were moved to the laboratory of astronomy belonging to the university or to the national observatory hidden from theNazis. After the war, the Astronomical Observatory was divided into three departments: the Astronomical, the Meteorological, and the Geodynamical.[33]
The large 25 in. (63 cm)Newall refractor thatThomas Cooke made forRobert Stirling Newall in 1869, was donated in 1890, by his sonHugh Newall, to theUniversity Observatory of Cambridge enabling Hugh Newall to make observations at the university. In 1955, because of Professor Plakidis's long collaboration on long-period variable stars with Sir Arthur Eddington the instrument was donated to the National Observatory of Athens and moved to the Penteli Astronomical Station.[34]
In 1999 the names of the four institutes of NOA were updated as follows:
In 2003 the Institute of Astroparticle Physics "NESTOR" became the fifth institute of NOA.
After a major reform in the structure of all research institutes in Greece in 2012, two of the institutes of NOA were merged and one (NESTOR) moved under another administrative unit. Currently NOA has the following three institutes:

The National Observatory of Athens operates in four locations:
The National Observatory of Athens handles the most antique meteorological station in Greece and one of the oldest inSouthern Europe. The station is located at the center ofAthens, in theThiseio neighbourhood (Hill of Nymphs). The A class Meteorological station has been located at the same position from the 11th of September 1890; while it started its operation in 1858 at a different location inThiseio.[35]
| Climate data for Downtown Athens (1991–2020), Extremes (1890–present) | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
| Record high °C (°F) | 22.8 (73.0) | 25.3 (77.5) | 28.2 (82.8) | 32.2 (90.0) | 37.6 (99.7) | 44.8 (112.6) | 42.8 (109.0) | 43.9 (111.0) | 38.7 (101.7) | 36.5 (97.7) | 30.5 (86.9) | 23.1 (73.6) | 44.8 (112.6) |
| Mean daily maximum °C (°F) | 13.3 (55.9) | 14.2 (57.6) | 17.0 (62.6) | 21.1 (70.0) | 26.5 (79.7) | 31.6 (88.9) | 34.3 (93.7) | 34.3 (93.7) | 29.6 (85.3) | 24.4 (75.9) | 18.9 (66.0) | 14.4 (57.9) | 23.3 (73.9) |
| Daily mean °C (°F) | 10.2 (50.4) | 10.8 (51.4) | 13.1 (55.6) | 16.7 (62.1) | 21.8 (71.2) | 26.6 (79.9) | 29.3 (84.7) | 29.4 (84.9) | 25.0 (77.0) | 20.3 (68.5) | 15.6 (60.1) | 11.6 (52.9) | 19.2 (66.6) |
| Mean daily minimum °C (°F) | 7.1 (44.8) | 7.3 (45.1) | 9.2 (48.6) | 12.3 (54.1) | 17.0 (62.6) | 21.6 (70.9) | 24.2 (75.6) | 24.4 (75.9) | 20.4 (68.7) | 16.2 (61.2) | 12.2 (54.0) | 8.7 (47.7) | 15.0 (59.0) |
| Record low °C (°F) | −6.5 (20.3) | −5.7 (21.7) | −2.6 (27.3) | 1.7 (35.1) | 6.2 (43.2) | 11.8 (53.2) | 16 (61) | 15.5 (59.9) | 8.9 (48.0) | 5.9 (42.6) | −1.1 (30.0) | −4.0 (24.8) | −6.5 (20.3) |
| Average rainfall mm (inches) | 55.6 (2.19) | 44.4 (1.75) | 45.6 (1.80) | 27.6 (1.09) | 20.7 (0.81) | 11.6 (0.46) | 10.7 (0.42) | 5.4 (0.21) | 25.8 (1.02) | 38.6 (1.52) | 70.8 (2.79) | 76.3 (3.00) | 433.1 (17.06) |
| Averagerelative humidity (%) | 72.0 | 70.0 | 66.0 | 60.0 | 56.0 | 50.0 | 42.0 | 47.0 | 57.0 | 66.0 | 72.0 | 73.0 | 60.9 |
| Averageultraviolet index | 2 | 3 | 5 | 7 | 9 | 10 | 10 | 9 | 6 | 4 | 2 | 2 | 6 |
| Source 1: Cosmos, scientific magazine of the National Observatory of Athens[36] | |||||||||||||
| Source 2: Meteoclub[37][38] | |||||||||||||
Theofficial site of the National Observatory of Athens (inGreek)
Theofficial site of the National Observatory of Athens (inEnglish)
The Central Premises inGoogle MapsThe Penteli's Astronomical Station inGoogle Maps
Ashort history of the National Observatory of Athens and its instruments (inGreek)
37°58′24.2″N23°43′5.6″E / 37.973389°N 23.718222°E /37.973389; 23.718222