Astrometry is a branch of astronomy that involves precise measurements of the positions and movements of stars and other celestial bodies. It provides the kinematics and physical origin of the Solar System and this galaxy, the Milky Way.
Arcturus is the brightest star in the northern constellation of Boötes. With an apparent visual magnitude of −0.05, it is the fourth-brightest star in the night sky, and the brightest in the northern celestial hemisphere. The name Arcturus originated from ancient Greece; it was then cataloged as α Boötis by Johann Bayer in 1603, which is Latinized to Alpha Boötis. Arcturus forms one corner of the Spring Triangle asterism.
A constellation is an area on the celestial sphere in which a group of visible stars forms a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object.
Hipparchus was a Greek astronomer, geographer, and mathematician. He is considered the founder of trigonometry, but is most famous for his incidental discovery of the precession of the equinoxes. Hipparchus was born in Nicaea, Bithynia, and probably died on the island of Rhodes, Greece. He is known to have been a working astronomer between 162 and 127 BC.
Polaris is a star in the northern circumpolar constellation of Ursa Minor. It is designated α Ursae Minoris and is commonly called the North Star or Pole Star. With an apparent magnitude that fluctuates around 1.98, it is the brightest star in the constellation and is readily visible to the naked eye at night. The position of the star lies less than 1° away from the north celestial pole, making it the current northern pole star. The stable position of the star in the Northern Sky makes it useful for navigation.
A star catalogue is an astronomical catalogue that lists stars. In astronomy, many stars are referred to simply by catalogue numbers. There are a great many different star catalogues which have been produced for different purposes over the years, and this article covers only some of the more frequently quoted ones. Star catalogues were compiled by many different ancient people, including the Babylonians, Greeks, Chinese, Persians, and Arabs. They were sometimes accompanied by a star chart for illustration. Most modern catalogues are available in electronic format and can be freely downloaded from space agencies' data centres. The largest is being compiled from the spacecraft Gaia and thus far has over a billion stars.
Proper motion is the astrometric measure of the observed changes in the apparent places of stars or other celestial objects in the sky, as seen from the center of mass of the Solar System, compared to the abstract background of the more distant stars.
Hipparcos was a scientific satellite of the European Space Agency (ESA), launched in 1989 and operated until 1993. It was the first space experiment devoted to precision astrometry, the accurate measurement of the positions of celestial objects on the sky. This permitted the first high-precision measurements of the intrinsic brightnesses, proper motions, and parallaxes of stars, enabling better calculations of their distance and tangential velocity. When combined with radial velocity measurements from spectroscopy, astrophysicists were able to finally measure all six quantities needed to determine the motion of stars. The resulting Hipparcos Catalogue, a high-precision catalogue of more than 118,200 stars, was published in 1997. The lower-precision Tycho Catalogue of more than a million stars was published at the same time, while the enhanced Tycho-2 Catalogue of 2.5 million stars was published in 2000. Hipparcos' follow-up mission, Gaia, was launched in 2013.
The Guide Star Catalog (GSC), also known as the Hubble Space Telescope, Guide Catalog (HSTGC), is a star catalog compiled to support the Hubble Space Telescope with targeting off-axis stars. GSC-I contained approximately 20,000,000 stars with apparent magnitudes of 6 to 15. GSC-II contains 945,592,683 stars out to magnitude 21. As far as possible, binary stars and non-stellar objects have been excluded or flagged as not meeting the requirements of Fine Guidance Sensors. This is the first full sky star catalog created specifically for navigation in outer space.
The Beehive Cluster, is an open cluster in the constellation Cancer. One of the nearest open clusters to Earth, it contains a larger population of stars than other nearby bright open clusters holding around 1,000 stars. Under dark skies, the Beehive Cluster looks like a small nebulous object to the naked eye, and has been known since ancient times. Classical astronomer Ptolemy described it as a "nebulous mass in the breast of Cancer". It was among the first objects that Galileo studied with his telescope.
Epsilon Pegasi, formally named Enif, is the brightest star in the northern constellation of Pegasus.
The Catasterismi or Catasterisms, is a lost work attributed to Eratosthenes of Cyrene. It was a comprehensive compendium of astral mythology including origin myths of the stars and constellations. Only a summary of the original work survives, called the Epitome Catasterismorum, by an unknown author sometimes referred to as pseudo-Eratosthenes.
In astronomy, Durchmusterung or Bonner Durchmusterung (BD) is an astrometric star catalogue of the whole sky, published by the Bonn Observatory in Germany from 1859 to 1863, with an extension published in Bonn in 1886. The name comes from Durchmusterung, a German word used for a systematic survey of objects or data. The term has sometimes been used for other astronomical surveys, including not only stars, but also the search for other celestial objects. Special tasks include celestial scanning in electromagnetic wavelengths shorter or longer than visible light waves.
Tyndale House is an independent biblical studies library in Cambridge, England, with a Christian foundation. Founded in 1945, it aims to provide specialist resources in support of research into the Old and New Testaments, along with relevant historical backgrounds.
Delta Ceti, Latinized from δ Ceti, is a single, blue-white hued star in the equatorial constellation of Cetus. The star's apparent visual magnitude of +4.06 means it is near to the cusp of the faintest third of the stars that are visible the ideally-placed naked eye. It is 0.3238° north of the celestial equator compared to the celestial north pole's 90°. The star is positioned about 0.74° WNW of the spiral galaxy M77, but which at apparent magnitude 9.6 needs magnification to be made out and has an apparent size of only 0.1° by 0.12°.
Agnes Smith Lewis (1843–1926) and Margaret Dunlop Gibson (1843–1920), nées Smith, were English Semitic scholars and travellers. As the twin daughters of John Smith of Irvine, Ayrshire, Scotland, they learned more than 12 languages between them, specialising in Arabic, Christian Palestinian Aramaic, and Syriac, and became acclaimed scholars in their academic fields, and benefactors to the Presbyterian Church of England, especially to Westminster College, Cambridge.
Codex Climaci rescriptus is a collective palimpsest manuscript consisting of several individual manuscripts (eleven) underneath with Christian Palestinian Aramaic texts of the Old and New Testament as well as two apocryphal texts, including the Dormition of the Mother of God, and is known as Uncial 0250 with a Greek uncial text of the New Testament and overwritten by Syriac treatises of Johannes Climacus : the scala paradisi and the liber ad pastorem. Paleographically the Greek text has been assigned to the 7th or 8th century, and the Aramaic text to the 6th century. It originates from Saint Catherine's Monastery going by the News Finds of 1975. Formerly it was classified for CCR 5 and CCR 6 as lectionary manuscript, with Gregory giving the number ℓ 1561 to it.
The barycentric celestial reference system (BCRS) is a coordinate system used in astrometry to specify the location and motions of astronomical objects. It was created in 2000 by the International Astronomical Union (IAU) to be the global standard reference system for objects located outside the gravitational vicinity of Earth: planets, moons, and other Solar System bodies, stars and other objects in the Milky Way galaxy, and extra-galactic objects.
Codex Sinaiticus Rescriptus mostly originating in Saint Catherine’s Monastery, Sinai is an accumulation of sixteen or even eighteen Christian Palestinian Aramaic palimpsest manuscripts containing Old Testament, Gospel and Epistles pericopes of diverse Lectionaries, various unidentified homilies and one by John Chrysostom, hagiographic texts as the Life of Pachomios, the Martyrdom of Philemon Martyrs, and the Catecheses by Cyril of Jerusalem. The manuscripts are recycled parchment material that were erased and reused by the tenth century Georgian scribe Ioane-Zosime for overwriting them with homilies and a Iadgari. Part of the parchment leaves had been brought by him from the Monastery of Saint Sabas, south of Jerusalem, when he moved to St Catherine’s Monastery and became there librarian. In the nineteenth century most of the codex was removed from the monastery at two periods. C. Tischendorf took two thirds in 1855 and 1857 with the Codex Sinaiticus to St Peterburg and handed it over to the Imperial Library, now the National Library of Russia, and the remaining third left on a clandestine route and found its way into various European and later also into US collections, at present in a Norwegian collection. From the New Finds of 1975 in the Monastery of Saint Catherine missing folios of some of the underlying manuscripts could be retrieved.
