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Dark Moon
The term dark moon describes the last visible crescent of a waning Moon. The duration of a dark moon varies between 1.5 and 3.5 days, depending on its ecliptic latitude. In current astronomical usage, the new moon occurs in the middle of this dark period, when the Moon and Sun are in conjunction. This definition has entered popular usage, so that calendars will typically indicate the date of the "new moon" rather than the "dark moon". Dark moon as the 30th division The ''Oxford English Dictionary'' defines the new moon as "the first visible crescent of the Moon, after conjunction with the Sun". ''Dark moon'' is a term used for a waning crescent moon. When the Moon's orbit is divided into 30 segments, as the ancient Greeks did in the time of Homer, the Babylonians did, and the Indians still do today (calling them ''tithi''), the last phase is called the "dark moon". In Greek, it was called the "old moon" and associated with Hecate. In India, it is called Amavasya and associa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tithi
In Vedic timekeeping, a ''tithi'' is a uration of two faces of moon that is observed from earth known as ''milа̄lyа̄'' (𑐩𑐶𑐮𑐵𑐮𑑂𑐫𑐵𑑅, मिलाल्याः) in Nepal Bhasa, or the time it takes for the longitudinal angle between the Moon and the Sun to increase by 12 °. In other words, a tithi is a time-duration between the consecutive epochs that correspond to when the longitudinal-angle between sun and moon is an integer multiple of 12°. Tithis begin at varying times of day and vary in duration from approximately 19 to approximately 26 hours. Every day of lunar month is called tithi. Panchanga A Hindu ''muhurta'' (forty-eight minute duration) can be represented in five attributes of Hindu astronomy namely, ''vara'' the weekday, ''tithi'', ''nakshatra'' the Moon's asterism, ''yoga'' the angular relationship between Sun and Moon and ''karana'' half of tithi. ''Tithi'' plays an important role along with ''nakshatra'' in Hindus' daily as wel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lunar Calendar
A lunar calendar is a calendar based on the monthly cycles of the Moon's phases (synodic months, lunations), in contrast to solar calendars, whose annual cycles are based only directly on the solar year. The most commonly used calendar, the Gregorian calendar, is a solar calendar system that originally evolved out of a lunar calendar system. A purely lunar calendar is also distinguished from a lunisolar calendar, whose lunar months are brought into alignment with the solar year through some process of intercalation. The details of when months begin vary from calendar to calendar, with some using new, full, or crescent moons and others employing detailed calculations. Since each lunation is approximately days, (which gives a mean synodic month as 29.53059 days or 29 days 12 hours 44 minutes and 3 seconds) it is common for the months of a lunar calendar to alternate between 29 and 30 days. Since the period of 12 such lunations, a lunar year, is 354 days, 8 h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lunar Theory
Lunar theory attempts to account for the motions of the Moon. There are many small variations (or perturbations) in the Moon's motion, and many attempts have been made to account for them. After centuries of being problematic, lunar motion can now be modeled to a very high degree of accuracy (see section Modern developments). Lunar theory includes: * the background of general theory; including mathematical techniques used to analyze the Moon's motion and to generate formulae and algorithms for predicting its movements; and also * quantitative formulae, algorithms, and geometrical diagrams that may be used to compute the Moon's position for a given time; often by the help of tables based on the algorithms. Lunar theory has a history of over 2000 years of investigation. Its more modern developments have been used over the last three centuries for fundamental scientific and technological purposes, and are still being used in that way. Applications Applications of lunar theory have i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arc (geometry)
In mathematics, a curve (also called a curved line in older texts) is an object similar to a line, but that does not have to be straight. Intuitively, a curve may be thought of as the trace left by a moving point. This is the definition that appeared more than 2000 years ago in Euclid's ''Elements'': "The urvedline is the first species of quantity, which has only one dimension, namely length, without any width nor depth, and is nothing else than the flow or run of the point which will leave from its imaginary moving some vestige in length, exempt of any width." This definition of a curve has been formalized in modern mathematics as: ''A curve is the image of an interval to a topological space by a continuous function''. In some contexts, the function that defines the curve is called a ''parametrization'', and the curve is a parametric curve. In this article, these curves are sometimes called ''topological curves'' to distinguish them from more constrained curves such a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Syzygy (astronomy)
In astronomy, a syzygy ( ; ) is a roughly straight-line configuration of three or more celestial bodies in a gravitational system. Overview The word is often used in reference to the Sun, Earth, and either the Moon or a planet, where the latter is in conjunction or opposition. Solar and lunar eclipses occur at times of syzygy, as do transits and occultations. The term is often applied when the Sun and Moon are in conjunction (new moon) or opposition (full moon). The word ''syzygy'' is often used to describe interesting configurations of astronomical objects in general. For example, one such case occurred on March 21, 1894, around 23:00 GMT, when Mercury transited the Sun as would have been seen from Venus, and Mercury and Venus both simultaneously transited the Sun as seen from Saturn. It is also used to describe situations when all the planets are on the same side of the Sun although they are ''not necessarily in a straight line'', such as on March 10, 1982. On June 3, 201 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angular Distance
Angular distance \theta (also known as angular separation, apparent distance, or apparent separation) is the angle between the two sightlines, or between two point objects as viewed from an observer. Angular distance appears in mathematics (in particular geometry and trigonometry) and all natural sciences (e.g. astronomy and geophysics). In the classical mechanics of rotating objects, it appears alongside angular velocity, angular acceleration, angular momentum, moment of inertia and torque. Use The term ''angular distance'' (or ''separation'') is technically synonymous with ''angle'' itself, but is meant to suggest the linear distance between objects (for instance, a couple of stars observed from Earth). Measurement Since the angular distance (or separation) is conceptually identical to an angle, it is measured in the same units, such as degrees or radians, using instruments such as goniometers or optical instruments specially designed to point in well-defined directions and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kali
Kali (; sa, काली, ), also referred to as Mahakali, Bhadrakali, and Kalika ( sa, कालिका), is a Hinduism, Hindu goddess who is considered to be the goddess of ultimate power, time, destruction and change in Shaktism. In this tradition, she is considered as a ferocious form of goddess Mahadevi, the supreme of all powers, or the ultimate reality. She is the first of the ten Mahavidyas in the Hindu Tantras (Hinduism), tantric tradition. Kali's earliest appearance is when she emerged from Shiva. She is regarded as the ultimate manifestation of Shakti, and the mother of all living beings. The goddess is stated to destroy evil in order to protect the innocent. Over time, Kali has been worshipped by devotional movements and Tàntric sects variously as the Divine Mother, Mother of the Universe, Principal energy Adi Shakti. Shaktism, Shakta Hindu and Tantra, Tantric sects additionally worship her as the ultimate reality or ''Brahman''. She is also seen as the divi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amavasya
Amāvásyā () is the lunar phase of the new moon in Sanskrit. Indian calendars use 30 lunar phases, called tithi in India. The dark moon tithi is when the Moon is within 12 degrees of the angular distance between the Sun and Moon before conjunction ( syzygy). The New Moon tithi (called Pratipada or Prathama) is the 12 angular degrees after syzygy. Amāvásyā is often translated as new moon since there is no standard term for the Moon before conjunction in English. Meaning of Amāvásyā In Sanskrit, "amā" means "together" and "vásya" means "to dwell" or "cohabit". It also means "na" +"ma"+"asya" meaning to "na" = "No, "ma"=Moon, "Asya"="There" in turn meaning to There is no Moon i.e., Moon is not visible. In the ''pūrṇimānta māna'' Hindu lunar calendar used in most parts of the Indian subcontinent, the lunar month starts on the day following the full moon or ''purnima'' and therefore Amāvásyā always falls in the middle of the month. However, in the '' amānta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hecate
Hecate or Hekate, , ; grc-dor, Ἑκάτᾱ, Hekátā, ; la, Hecatē or . is a goddess in ancient Greek religion and mythology, most often shown holding a pair of torches, a key, snakes, or accompanied by dogs, and in later periods depicted as three-formed or triple-bodied. She is variously associated with crossroads, entrance-ways, night, light, magic, witchcraft, the Moon, knowledge of herbs and poisonous plants, graves, ghosts, necromancy, and sorcery.Seyffert, s.vHecate/ref>d'Este, Sorita & Rankine, David, Hekate Liminal Rites, Avalonia, 2009. Her earliest appearance in literature was in Hesiod's ''Theogony'' in the 8th century BCE as a goddess of great honour with domains in sky, earth, and sea. Her place of origin is debated by scholars, but she had popular followings amongst the witches of Thessaly and an important sanctuary among the Carian Greeks of Asia Minor in Lagina. Her oldest known representation was found in Selinunte, in Sicily. Hecate was one of several de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Babylonia
Babylonia (; Akkadian: , ''māt Akkadī'') was an ancient Akkadian-speaking state and cultural area based in the city of Babylon in central-southern Mesopotamia (present-day Iraq and parts of Syria). It emerged as an Amorite-ruled state c. 1894 BCE. During the reign of Hammurabi and afterwards, Babylonia was called "the country of Akkad" (''Māt Akkadī'' in Akkadian), a deliberate archaism in reference to the previous glory of the Akkadian Empire. It was often involved in rivalry with the older state of Assyria to the north and Elam to the east in Ancient Iran. Babylonia briefly became the major power in the region after Hammurabi ( fl. c. 1792–1752 BCE middle chronology, or c. 1696–1654 BCE, short chronology) created a short-lived empire, succeeding the earlier Akkadian Empire, Third Dynasty of Ur, and Old Assyrian Empire. The Babylonian Empire rapidly fell apart after the death of Hammurabi and reverted to a small kingdom. Like Assyria, the Babylonian state retained ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crescent
A crescent shape (, ) is a symbol or emblem used to represent the lunar phase in the first quarter (the "sickle moon"), or by extension a symbol representing the Moon itself. In Hinduism, Lord Shiva is often shown wearing a crescent moon on his head symbolising that the lord is the master of time and is himself timeless. It is used as the astrological symbol for the Moon, and hence as the alchemical symbol for silver. It was also the emblem of Diana/Artemis, and hence represented virginity. In Christianity Marian veneration, it is associated with the Virgin Mary. From its use as roof finial in Ottoman era mosques, it has also become associated with Islam, and the crescent was introduced as chaplain badge for Muslim chaplains in the US military in 1993.On December 14, 1992, the Army Chief of Chaplains requested that an insignia be created for future Muslim chaplains, and the design (a crescent) was completed January 8, 1993. Emerson, William K., ''Encyclopedia of United St ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
