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.
Mira, designation Omicron Ceti, is a red-giant star estimated to be 200–300 light-years from the Sun in the constellation Cetus.
In textual studies, a palimpsest is a manuscript page, either from a scroll or a book, from which the text has been scraped or washed off in preparation for reuse in the form of another document. Parchment was made of lamb, calf, or kid skin and was expensive and not readily available, so, in the interest of economy, a page was often re-used by scraping off the previous writing. In colloquial usage, the term palimpsest is also used in architecture, archaeology and geomorphology to denote an object made or worked upon for one purpose and later reused for another; for example, a monumental brass the reverse blank side of which has been re-engraved.
Claudius Ptolemy was an Alexandrian mathematician, astronomer, astrologer, geographer, and music theorist who wrote about a dozen scientific treatises, three of which were important to later Byzantine, Islamic, and Western European science. The first was his astronomical treatise now known as the Almagest, originally entitled Mathematical Treatise. The second is the Geography, which is a thorough discussion on maps and the geographic knowledge of the Greco-Roman world. The third is the astrological treatise in which he attempted to adapt horoscopic astrology to the Aristotelian natural philosophy of his day. This is sometimes known as the Apotelesmatika but more commonly known as the Tetrábiblos, from the Koine Greek meaning "Four Books", or by its Latin equivalent Quadripartite.
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.
Aratus was a Greek didactic poet. His major extant work is his hexameter poem Phenomena, the first half of which is a verse setting of a lost work of the same name by Eudoxus of Cnidus. It describes the constellations and other celestial phenomena. The second half is called the Diosemeia, and is chiefly about weather lore. Although Aratus was somewhat ignorant of Greek astronomy, his poem was very popular in the Greek and Roman world, as is proven by the large number of commentaries and Latin translations, some of which survive.
The Almagest is a 2nd-century mathematical and astronomical treatise on the apparent motions of the stars and planetary paths, written by Claudius Ptolemy in Koine Greek. One of the most influential scientific texts in history, it canonized a geocentric model of the Universe that was accepted for more than 1,200 years from its origin in Hellenistic Alexandria, in the medieval Byzantine and Islamic worlds, and in Western Europe through the Middle Ages and early Renaissance until Copernicus. It is also a key source of information about ancient Greek astronomy.
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 International Celestial Reference System (ICRS) is the current standard celestial reference system adopted by the International Astronomical Union (IAU). Its origin is at the barycenter of the Solar System, with axes that are intended to "show no global rotation with respect to a set of distant extragalactic objects". This fixed reference system differs from previous reference systems, which had been based on Catalogues of Fundamental Stars that had published the positions of stars based on direct "observations of [their] equatorial coordinates, right ascension and declination" and had adopted as "privileged axes ... the mean equator and the dynamical equinox" at a particular date and time.
Gamma Eridani, formally named Zaurak, is a variable star in the constellation of Eridanus. It is visible to the naked eye with an apparent visual magnitude that varies around 2.9, and lies at a distance of about 203 light years from the Sun, as determined by the Hipparcos astrometry satellite.
The Catasterismi or Catasterisms is a lost work by 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.
Ancient Greek astronomy is the astronomy written in the Greek language during classical antiquity. Greek astronomy is understood to include the Ancient Greek, Hellenistic, Greco-Roman, and late antique eras. Ancient Greek astronomy can be divided into three primary phases: Classical Greek Astronomy, which encompassed the 5th and 4th centuries BC, and Hellenistic Astronomy, which encompasses the subsequent period until the formation of the Roman Empire ca. 30 BC, and finally Greco-Roman astronomy, which refers to the continuation of the tradition of Greek astronomy in the Roman world. During the Hellenistic era and onwards, Greek astronomy expanded beyond the geographic region of Greece as the Greek language had become the language of scholarship throughout the Hellenistic world, in large part delimited by the boundaries of the Macedonian Empire established by Alexander the Great. The most prominent and influential practitioner of Greek astronomy was Ptolemy, whose treatise Almagest shaped astronomical thinking until the modern era. Most of the most prominent constellations known today are taken from Greek astronomy, albeit via the terminology they took on in Latin.
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.
Codex Climaci rescriptus is a collective palimpsest manuscript consisting of several individual manuscripts underneath, 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 New 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.
Codex Sinaiticus Rescriptus, mostly originating in Saint Catherine's Monastery, Sinai from Sin. Georg. 34; Tsagareli 81, is an accumulation of nineteen Christian Palestinian Aramaic palimpsest manuscripts containing Old Testament, Gospel and Epistles pericopes of diverse Lectionaries, among them two witnesses of the Old Jerusalem Lectionary, various unidentified homilies and two by John Chrysostom, hagiographic texts as the Life of Pachomios, the Martyrdom of Philemon Martyrs, and the Catecheses by Cyril of Jerusalem. The palimpsests 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 in the Kidron Valley, 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 [so-called collection of Dr Friedrich Grote (1862-1922)] 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, with one connected to Princeton, Garrett MS 24.
