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Occultation Astronomy
An occultation is an event that occurs when one object is hidden from the observer by another object that passes between them. The term is often used in astronomy, but can also refer to any situation in which an object in the foreground blocks from view (occults) an object in the background. In this general sense, occultation applies to the visual scene observed from low-flying aircraft (or computer-generated imagery) when foreground objects obscure distant objects dynamically, as the scene changes over time. If the closer body does not entirely conceal the farther one, the event is called a ''transit''. Both transit and occultation may be referred to generally as ''occlusion''; and if a shadow is cast onto the observer, it is called an eclipse. The symbol for an occultation, and especially a solar eclipse, is 🝵 (U+1F775 🝵). Occultations by the Moon The term occultation is most frequently used to describe lunar occultations, those relatively frequent occasions when ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Regulus
Regulus is the brightest object in the constellation Leo (constellation), Leo and one of the List of brightest stars, brightest stars in the night sky. It has the Bayer designation designated α Leonis, which is Latinisation of names, Latinized to Alpha Leonis, and abbreviated Alpha Leo or α Leo. Regulus appears singular, but is actually a quadruple star system composed of four stars that are organized into two pairs. The Binary star#Spectroscopic binaries, spectroscopic binary Regulus A consists of a blue-white main-sequence star and its companion, a pre-white dwarf. The system lies approximately 79 light years from the Solar System. HD 87884 is separated from Regulus by and is itself a close pair. Regulus, along with five slightly dimmer stars (Zeta Leonis, Mu Leonis, Gamma Leonis, Epsilon Leonis, and Eta Leonis) have collectively been called 'the Sickle', which is an Asterism (astronomy), asterism that marks the head of Leo. Nomenclature ''α Leonis'' (Latinized ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Effective Temperature
The effective temperature of a body such as a star or planet is the temperature of a black body that would emit the same total amount of electromagnetic radiation. Effective temperature is often used as an estimate of a body's surface temperature when the body's emissivity curve (as a function of wavelength) is not known. When the star's or planet's net emissivity in the relevant wavelength band is less than unity (less than that of a black body), the actual temperature of the body will be higher than the effective temperature. The net emissivity may be low due to surface or atmospheric properties, such as the greenhouse effect. Star The effective temperature of a star is the temperature of a black body with the same luminosity per ''surface area'' () as the star and is defined according to the Stefan–Boltzmann law . Notice that the total ( bolometric) luminosity of a star is then , where is the stellar radius. The definition of the stellar radius is obviously not ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Binary Star
A binary star or binary star system is a system of two stars that are gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved as separate stars using a telescope, in which case they are called ''visual binaries''. Many visual binaries have long orbital periods of several centuries or millennia and therefore have orbits which are uncertain or poorly known. They may also be detected by indirect techniques, such as spectroscopy (''spectroscopic binaries'') or astrometry (''astrometric binaries''). If a binary star happens to orbit in a plane along our line of sight, its components will eclipse and transit each other; these pairs are called ''eclipsing binaries'', or, together with other binaries that change brightness as they orbit, ''photometric binaries''. If components in binary star systems are close enough, they can gravitationally distort each other's outer stellar atmospheres. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lunar Topography
Selenography is the study of the surface and physical features of the Moon (also known as geography of the Moon, or selenodesy). Like geography and areography, selenography is a subdiscipline within the field of planetary science. Historically, the principal concern of selenographists was the mapping and naming of the lunar terrane identifying maria, craters, mountain ranges, and other various features. This task was largely finished when high resolution images of the near and far sides of the Moon were obtained by orbiting spacecraft during the early space era. Nevertheless, some regions of the Moon remain poorly imaged (especially near the poles) and the exact locations of many features (like crater depths) are uncertain by several kilometers. Today, selenography is considered to be a subdiscipline of selenology, which itself is most often referred to as simply "lunar science." History The word" selenography" is derived from the Greek word ''Σελήνη'' (Selene, m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grazing Lunar Occultation
__NOTOC__ A grazing lunar occultation (also lunar grazing occultation, lunar graze, or just graze) is a lunar occultation in which as the occulted star disappears and reappears intermittently on the edge of the Moon. A team of many observers can combine grazes and reconstruct an accurate profile of the limb lunar terrain. Since graze paths rarely pass over established astronomical observatory, observatories, amateur astronomers use portable observing equipment and travel to sites along the shadow path limits. The goal is to report the Coordinated Universal Time, UTC of each event as accurately as possible, and Global Positioning System, GPS disciplined devices are frequently used as the time-base. Two methods are used to observe: * visual – the observer has an audible UTC beeping device (e.g. a shortwave radio tuned to WWV (radio station), WWV) and an audio recorder (e.g. a tape recorder) and watches the target through the telescope, and calls 'Gone' when the star disappears, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Total Solar Eclipse - April 8, 2024 - Mazatlan Mexico - Ten Minute Time Lapse V2 1080p
Total may refer to: Mathematics * Total, the summation of a set of numbers * Total order, a partial order without incomparable pairs * Total relation, which may also mean ** connected relation (a binary relation in which any two elements are comparable). * Total function, a partial function that is also a total relation Business * TotalEnergies, a French petroleum company, formerly known as Total * Total (cereal), a food brand by General Mills * Total, a brand of strained yogurt made by Fage * Total, a database management system marketed by Cincom Systems * Total Linhas Aéreas, a Brazilian airline * Total, a line of dental products by Colgate Music and culture * Total (group), an American R&B girl group * '' Total: From Joy Division to New Order'', a compilation album * ''Total'' (Sebastian album) * ''Total'' (Total album) * ''Total'' (Teenage Bottlerocket album) * ''Total'' (Seigmen album) * ''Total'' (Wanessa album) * ''Total'' (Belinda Peregrín album) * ''Total 1'', ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saturn Occultation
Saturn is the sixth planet from the Sun and the second largest in the Solar System, after Jupiter. It is a gas giant, with an average radius of about 9 times that of Earth. It has an eighth the average density of Earth, but is over 95 times more massive. Even though Saturn is almost as big as Jupiter, Saturn has less than a third its mass. Saturn orbits the Sun at a distance of , with an orbital period of 29.45 years. Saturn's interior is thought to be composed of a rocky core, surrounded by a deep layer of metallic hydrogen, an intermediate layer of liquid hydrogen and liquid helium, and an outer layer of gas. Saturn has a pale yellow hue, due to ammonia crystals in its upper atmosphere. An electrical current in the metallic hydrogen layer is thought to give rise to Saturn's planetary magnetic field, which is weaker than Earth's, but has a magnetic moment 580 times that of Earth because of Saturn's greater size. Saturn's magnetic field strength is about a twentieth tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pleiades
The Pleiades (), also known as Seven Sisters and Messier 45 (M45), is an Asterism (astronomy), asterism of an open cluster, open star cluster containing young Stellar classification#Class B, B-type stars in the northwest of the constellation Taurus (constellation), Taurus. At a distance of about 444 light-years, it is among the nearest star clusters to Earth and the nearest Messier object to Earth, being the most obvious star cluster to the naked eye in the night sky. It is also observed to house the reflection nebula NGC 1432, an HII region. Around 2330 BC it marked the vernal point. Due to the brightness of its stars, the Pleiades is viewable from most areas on Earth, even in locations with significant light pollution. The cluster is dominated by OB star, hot blue luminous stars that have formed within the last 100 million years. Reflection nebulae around the brightest stars were once thought to be leftover material from their formation, but are now considered likely to be an u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deep-sky Object
A deep-sky object (DSO) is any astronomical object that is not an individual star or Solar System object (such as Sun, Moon, planet, comet, etc.). The classification is used for the most part by amateur astronomers to denote visually observed faint naked eye and Optical telescope, telescopic objects such as star clusters, nebulae and galaxy, galaxies. This distinction is practical and technical, implying a variety of instruments and techniques appropriate to observation, and does not distinguish the nature of the object itself. Origins and classification Classifying non-stellar astronomical objects began soon after the invention of the telescope. One of the earliest comprehensive lists was Charles Messier's 1774 Messier catalog, which included 103 "nebulae" and other faint fuzzy objects he considered a nuisance since they could be mistaken for comets, the objects he was actually searching for. As telescopes improved these faint nebulae would be broken into more descriptive scien ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pollux (star)
Pollux is the brightest star in the constellation of Gemini (constellation), Gemini. It has the Bayer designation β Geminorum, which is Latinisation of names, Latinised to Beta Geminorum and abbreviated Beta Gem or β Gem. This is an orange-hued, stellar evolution, evolved red giant located at a distance of 34 light-years, making it the List of nearest giant stars, closest red giant (and giant star) to the Sun. Since 1943, the stellar spectrum, spectrum of this star has served as one of the stable anchor points by which other stars are classified. In 2006 an exoplanet (designated Pollux b or β Geminorum b, later named Thestias) was announced to be orbiting it. Nomenclature ''β Geminorum'' (Latinisation of names, Latinised to ''Beta Geminorum'') is the star's Bayer designation. The traditional name ''Pollux'' refers to the twins Castor and Pollux in Greek mythology, Greek and Roman mythology. In 2016, the International Astronomical Union organized a IAU Working ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
