An eclipse is an astronomical event that occurs when an astronomical object is temporarily obscured, either by passing into the shadow of another body or by having another body pass between it and the viewer. This alignment of three celestial objects is known as a syzygy. Apart from syzygy, the term eclipse is used when a spacecraft reaches a position where it can observe two celestial bodies so aligned. An eclipse is the result of either a transit; the term eclipse is most used to describe either a solar eclipse, when the Moon's shadow crosses the Earth's surface, or a lunar eclipse, when the Moon moves into the Earth's shadow. However, it can refer to such events beyond the Earth–Moon system: for example, a planet moving into the shadow cast by one of its moons, a moon passing into the shadow cast by its host planet, or a moon passing into the shadow of another moon. A binary star system can produce eclipses if the plane of the orbit of its constituent stars intersects the observer's position.
For the special cases of solar and lunar eclipses, these only happen during an "eclipse season", the two times of each year when the plane of the Earth's orbit around the Sun crosses with the plane of the Moon's orbit around the Earth. The type of solar eclipse that happens during each season depends on apparent sizes of the Sun and Moon. If the orbit of the Earth around the Sun, the Moon's orbit around the Earth were both in the same plane with each other eclipses would happen each and every month. There would be a lunar eclipse at every full moon, a solar eclipse at every new moon, and if both orbits were circular each solar eclipse would be the same type every month. It is because of non-circular differences that eclipses are not a common event. Lunar eclipses can be viewed from the entire nightside half of the Earth, but solar eclipses total eclipses occurring at any one particular point on the Earth's surface, are rare events that can be many decades apart. The term is derived from the ancient Greek noun ἔκλειψις, which means "the abandonment", "the downfall", or "the darkening of a heavenly body", derived from the verb ἐκλείπω which means "to abandon", "to darken", or "to cease to exist," a combination of prefix ἐκ-, from preposition ἐκ, "out," and of verb λείπω, "to be absent".
For any two objects in space, a line can be extended from the first through the second. The latter object will block some amount of light being emitted by the former, creating a region of shadow around the axis of the line; these objects are moving with respect to each other and their surroundings, so the resulting shadow will sweep through a region of space, only passing through any particular location in the region for a fixed interval of time. As viewed from such a location, this shadowing event is known as an eclipse; the cross-section of the objects involved in an astronomical eclipse are disk shaped. The region of an object's shadow during an eclipse is divided into three parts: The umbra, within which the object covers the light source. For the Sun, this light source is the photosphere; the antumbra, extending beyond the tip of the umbra, within which the object is in front of the light source but too small to cover it. The penumbra, within which the object is only in front of the light source.
A total eclipse occurs when the observer is within the umbra, an annular eclipse when the observer is within the antumbra, a partial eclipse when the observer is within the penumbra. During a lunar eclipse only the umbra and penumbra are applicable; this is because Earth's apparent diameter from the viewpoint of the Moon is nearly four times that of the Sun. The same terms may be used analogously in describing other eclipses, e.g. the antumbra of Deimos crossing Mars, or Phobos entering Mars's penumbra. The first contact occurs when the eclipsing object's disc first starts to impinge on the light source. For spherical bodies, when the occulting object is smaller than the star, the length of the umbra's cone-shaped shadow is given by: L = r ⋅ R o R s − R o where Rs is the radius of the star, Ro is the occulting object's radius, r is the distance from the star to the occulting object. For Earth, on average L is equal to 1.384×106 km, much larger than the Moon's semimajor axis of 3.844×105 km. Hence the umbral cone of the Earth can envelop the Moon during a lunar eclipse.
If the occulting object has an atmosphere, some of the luminosity of the star can be refracted into the volume of the umbra. This occurs, for example, during an eclipse of the Moon by the Earth—producing a faint, ruddy illumination of the Moon at totality. On Earth, the shadow cast during an eclipse moves approximately at 1 km per sec; this depends on the angle in which it is moving. An eclipse cycle takes place; this happens. A particular instance is the saros, which results in a repetition of a solar or lunar eclipse every 6,585.3 days, or a little over 18 years. Because this is not a
The lunar phase or phase of the Moon is the shape of the directly sunlit portion of the Moon as viewed from Earth. The lunar phases and cyclically change over the period of a synodic month, as the orbital positions of the Moon around Earth and of Earth around the Sun shift; the Moon's rotation is tidally locked by Earth's gravity. This near side is variously sunlit, depending on the position of the Moon in its orbit. Thus, the sunlit portion of this face can vary from 0% to 100%; the lunar terminator is the boundary between the darkened hemispheres. Each of the four "intermediate" lunar phases is around 7.4 days, but this varies due to the elliptical shape of the Moon's orbit. Aside from some craters near the lunar poles, such as Shoemaker, all parts of the Moon see around 14.77 days of daylight, followed by 14.77 days of "night". In western culture, the four principal phases of the Moon are new moon, first quarter, full moon, third quarter; these are the instances when the Moon's ecliptic longitude and the Sun's ecliptic longitude differ by 0°, 90°, 180°, 270°, respectively.
Each of these phases occur at different times when viewed from different points on Earth. During the intervals between principal phases, the Moon's apparent shape is either crescent or gibbous; these shapes, the periods when the Moon shows them, are called the intermediate phases and last one-quarter of a synodic month, or 7.38 days, on average. However, their durations vary because the Moon's orbit is rather elliptical, so the satellite's orbital speed is not constant; the descriptor waxing is used for an intermediate phase when the Moon's apparent shape is thickening, from new to full moon, waning when the shape is thinning. The eight principal and intermediate phases are given the following names, in sequential order: Non-Western cultures may use a different number of lunar phases; when the Sun and Moon are aligned on the same side of the Earth, the Moon is "new", the side of the Moon facing Earth is not illuminated by the Sun. As the Moon waxes, the lunar phases progress through new moon, crescent moon, first-quarter moon, gibbous moon, full moon.
The Moon is said to wane as it passes through the gibbous moon, third-quarter moon, crescent moon, back to new moon. The terms old moon and new moon are not interchangeable; the "old moon" is a waning sliver until the moment it aligns with the Sun and begins to wax, at which point it becomes new again. Half moon is used to mean the first- and third-quarter moons, while the term quarter refers to the extent of the Moon's cycle around the Earth, not its shape; when an illuminated hemisphere is viewed from a certain angle, the portion of the illuminated area, visible will have a two-dimensional shape as defined by the intersection of an ellipse and circle. If the half-ellipse is convex with respect to the half-circle the shape will be gibbous, whereas if the half-ellipse is concave with respect to the half-circle the shape will be a crescent; when a crescent moon occurs, the phenomenon of earthshine may be apparent, where the night side of the Moon dimly reflects indirect sunlight reflected from Earth.
In the Northern Hemisphere, if the left side of the Moon is dark the bright part is thickening, the Moon is described as waxing. If the right side of the Moon is dark the bright part is thinning, the Moon is described as waning. Assuming that the viewer is in the Northern Hemisphere, the right side of the Moon is the part, always waxing. In the Southern Hemisphere, the Moon is observed from a perspective inverted, or rotated 180°, to that of the Northern and to all of the images in this article, so that the opposite sides appear to wax or wane. Closer to the Equator, the lunar terminator will appear horizontal during the evening. Since the above descriptions of the lunar phases only apply at middle or high latitudes, observers moving towards the tropics from northern or southern latitudes will see the Moon rotated anti-clockwise or clockwise with respect to the images in this article; the lunar crescent can open upward or downward, with the "horns" of the crescent pointing up or down, respectively.
When the Sun appears above the Moon in the sky, the crescent opens downward. The crescent Moon is most and brightly visible when the Sun is below the horizon, which implies that the Moon must be above the Sun, the crescent must open upward; this is therefore the orientation in which the crescent Moon is most seen from the tropics. The waxing and waning crescents look similar; the waxing crescent appears in the western sky in the evening, the waning crescent in the eastern sky in the morning. When the Moon as seen from Earth is a narrow crescent, Earth as viewed from the Moon is fully lit by the Sun; the dark side of the Moon is dimly illuminated by indirect sunlight reflected from Earth, but is bright enough to be visible from Earth. This phenomenon is called earthshine and sometimes picturesquely described as "the old moon in the new
A calendar is a system of organizing days for social, commercial or administrative purposes. This is done by giving names to periods of time days, weeks and years. A date is the designation of a specific day within such a system. A calendar is a physical record of such a system. A calendar can mean a list of planned events, such as a court calendar or a or chronological list of documents, such as a calendar of wills. Periods in a calendar are though not synchronised with the cycle of the sun or the moon; the most common type of pre-modern calendar was the lunisolar calendar, a lunar calendar that adds one intercalary month to remain synchronised with the solar year over the long term. The term calendar is taken from calendae, the term for the first day of the month in the Roman calendar, related to the verb calare "to call out", referring to the "calling" of the new moon when it was first seen. Latin calendarium meant "account book, register"; the Latin term was adopted in Old French as calendier and from there in Middle English as calender by the 13th century.
A calendar can be on paper or electronic device. The course of the sun and the moon are the most salient natural recurring events useful for timekeeping, thus in pre-modern societies worldwide lunation and the year were most used as time units; the Roman calendar contained remnants of a ancient pre-Etruscan 10-month solar year. The first recorded physical calendars, dependent on the development of writing in the Ancient Near East, are the Bronze Age Egyptian and Sumerian calendars. A large number of Ancient Near East calendar systems based on the Babylonian calendar date from the Iron Age, among them the calendar system of the Persian Empire, which in turn gave rise to the Zoroastrian calendar and the Hebrew calendar. A great number of Hellenic calendars developed in Classical Greece, in the Hellenistic period gave rise to both the ancient Roman calendar and to various Hindu calendars. Calendars in antiquity were lunisolar, depending on the introduction of intercalary months to align the solar and the lunar years.
This was based on observation, but there may have been early attempts to model the pattern of intercalation algorithmically, as evidenced in the fragmentary 2nd-century Coligny calendar. The Roman calendar was reformed by Julius Caesar in 45 BC; the Julian calendar was no longer dependent on the observation of the new moon but followed an algorithm of introducing a leap day every four years. This created a dissociation of the calendar month from the lunation; the Islamic calendar is based on the prohibition of intercalation by Muhammad, in Islamic tradition dated to a sermon held on 9 Dhu al-Hijjah AH 10. This resulted in an observation-based lunar calendar that shifts relative to the seasons of the solar year; the first calendar reform of the early modern era was the Gregorian calendar, introduced in 1582 based on the observation of a long-term shift between the Julian calendar and the solar year. There have been a number of modern proposals for reform of the calendar, such as the World Calendar, International Fixed Calendar, Holocene calendar, the Hanke-Henry Permanent Calendar.
Such ideas are mooted from time to time but have failed to gain traction because of the loss of continuity, massive upheaval in implementation, religious objections. A full calendar system has a different calendar date for every day, thus the week cycle is by itself not a full calendar system. The simplest calendar system just counts time periods from a reference date; this applies for Unix Time. The only possible variation is using a different reference date, in particular, one less distant in the past to make the numbers smaller. Computations in these systems are just a matter of subtraction. Other calendars have one larger units of time. Calendars that contain one level of cycles: week and weekday – this system is not common year and ordinal date within the year, e.g. the ISO 8601 ordinal date systemCalendars with two levels of cycles: year and day – most systems, including the Gregorian calendar, the Islamic calendar, the Solar Hijri calendar and the Hebrew calendar year and weekday – e.g. the ISO week dateCycles can be synchronized with periodic phenomena: Lunar calendars are synchronized to the motion of the Moon.
Solar calendars are based on perceived seasonal changes synchronized to the apparent motion of the Sun. Lunisolar calendars are based on a combination of both solar and lunar reckonings; the week cycle is an example of one, not synchronized to any external phenomenon. A calendar includes more than one type of cycle, or has both cyclic and non-cyclic elements. Most calendars incorporate more complex cycles. For example, the vast majority of them track years, months and days; the seven-day week is universal, though its use varies. It has run uninterrupted for millennia. Solar calendars assign a date to each solar day. A day may consist of the period between sunrise and sunset, with
A diary is a record with discrete entries arranged by date reporting on what has happened over the course of a day or other period. A personal diary may include a person's experiences, and/or feelings, excluding comments on current events outside the writer's direct experience. Someone who keeps a diary is known as a diarist. Diaries undertaken for institutional purposes play a role in many aspects of human civilization, including government records, business ledgers, military records. In British English, the word may denote a preprinted journal format. A diary is a collection of notes. Today the term is employed for personal diaries intended to remain private or to have a limited circulation amongst friends or relatives; the word "journal" may be sometimes used for "diary," but a diary has daily entries, whereas journal-writing can be less frequent. Although a diary may provide information for a memoir, autobiography or biography, it is written not with the intention of being published as it stands, but for the author's own use.
In recent years, there is internal evidence in some diaries that they are written with eventual publication in mind, with the intention of self-vindication, or for profit. By extension the term diary is used to mean a printed publication of a written diary; the word diary comes from the Latin diarium. The word journal comes from the same root through Old French jurnal; the earliest use of the word refers to a book in which a daily record was written was in Ben Jonson's comedy Volpone in 1605. The oldest extant diaries come from Middle Eastern and East Asian cultures, although the earlier work To Myself, today known as the Meditations, written in Greek by the Roman Emperor Marcus Aurelius in the second half of the 2nd century AD displays many characteristics of a diary. Pillowbooks of Japanese court ladies and Asian travel journals offer some aspects of this genre of writing, although they consist of diurnal records; the scholar Li Ao, for example, kept a diary of his journey through southern China.
In the medieval Near East, Arabic diaries were written from before the 10th century. The earliest surviving diary of this era which most resembles the modern diary was that of Ibn Banna' in the 11th century, his diary is the earliest known to be arranged in order of date much like modern diaries. The precursors of the diary in the modern sense include daily notes of medieval mystics, concerned with inward emotions and outward events perceived as spiritually important. From the Renaissance on, some individuals wanted not only to record events, as in medieval chronicles and itineraries, but to put down their own opinions and express their hopes and fears, without any intention to publish these notes. One of the early preserved examples is the anonymous Journal d'un bourgeois de Paris that covers the years 1405–49, giving subjective commentaries on the current events. Famous 14th- to 16th-century Renaissance examples, which appeared much as books, were the diaries by the Florentines Buonaccorso Pitti and Gregorio Dati and the Venetian Marino Sanuto the Younger.
Here we find records of less important everyday occurrences together with much reflection, emotional experience and personal impressions. In 1908 the Smythson company created the first featherweight diary, enabling diaries to be carried about. Many diaries of notable figures have been published and form an important element of autobiographical literature. Samuel Pepys is the earliest diarist, well known today. Pepys was amongst the first who took the diary beyond mere business transaction notation, into the realm of the personal. Pepys' contemporary John Evelyn kept a notable diary, their works are among the most important primary sources for the English Restoration period, consist of eyewitness accounts of many great events, such as the Great Plague of London, the Great Fire of London; the practice of posthumous publication of diaries of literary and other notables began in the 19th century. As examples, the Grasmere Journal of Dorothy Wordsworth was published in 1897. Among important U. S. Civil War diaries are those of George Templeton Strong, a New York City lawyer, Mary Chesnut, the wife of a Confederate officer.
The diary of Jemima Condict, living in the area of what is now West Orange, New Jersey, includes local observations of the American Revolutionary War. Since the 19th century the publication of diaries by their authors has become commonplace – notably amongst politicians seeking justification but amongst artists and litterateurs of all descriptions. Amongst late 20th-century British published political diaries, those of Richard Crossman, Tony Benn and Alan Clark are representative, the latter being more indiscreet in the tradition of the diaries of Chips Channon. In Britain in the field of the arts notable diaries were published by James Lees-Milne, Roy Strong and Peter Hall. Harold Nicolson in the mid-20th century covered the arts. One of the m
The Rumi calendar, a specific calendar based on the Julian calendar was used by the Ottoman Empire after Tanzimat and by its successor, the Republic of Turkey until 1926. It is a solar based calendar, assigning a date to each solar day. In the Islamic state of the Ottoman Empire, the religious Islamic calendar was in use, within which days are numbered within each lunar phase cycle; because the length of the lunar month is not an fraction of the length of the tropical year, a purely lunar calendar drifts relative to the seasons. In 1677, Head Treasurer Hasan Pasha under Sultan Mehmed IV proposed the correction of financial records by dropping one year every 33 years, resulting from the difference between the lunar Islamic calendar and the solar Julian calendar. In 1740 during the reign of Sultan Mahmud I, March was adopted as the first month of the fiscal year for the payment of taxes and dealings with government officials instead of Muharram following Treasurer Atıf Efendi's proposal. Proposed by Treasurer Moralı Osman Efendi during the reign of Sultan Abdul Hamid I, the range of the fiscal calendar applications was extended in 1794 to state expenditures and payments in order to prevent surplus cost arising from the time difference between the Islamic and Julian calendar.
The Julian calendar, used from 1677 AD on for fiscal matters only, was adopted on March 13, 1840 AD, in the frame of Tanzimat reforms shortly after the accession to the throne of Sultan Abdülmecid I, as the official calendar for all civic matters and named "Rumi calendar". The counting of years began with the year 622 AD, when Muhammad and his followers emigrated from Mecca to Medina, the same event marking the start of the Islamic calendar; the months and days of the Julian calendar were used, the year starting in March. However, in 1256 AH the difference between the Hijri and the Gregorian calendars amounted to 584 years. With the change from lunar calendar to solar calendar, the difference between the Rumi calendar and the Julian or Gregorian calendar remained a constant 584 years. Since the Julian to Gregorian calendar changeover was being adopted in neighboring countries, the Rumi calendar was realigned to the Gregorian calendar in February 1917, leaving the difference of 584 years unchanged, however.
Thus, after February 15, 1332 AH, the next day instead of being February 16 became March 1, 1333 AH. The year 1333 AH was made into a year with only ten months, running from March 1 to December 31. January 1, AD 1918 thus became January 1, AH 1334; the Rumi calendar remained in use after the dissolution of the Ottoman Empire into the first years of the succeeding Republic of Turkey. The use of the AH era was abandoned as part of Atatürk's reforms by an act of December 26, 1341 AH and was replaced by the common era from 1926; the names of four months that occur in pairs in the Semitic/Arabic naming system were changed on January 10, 1945 to Turkish language names, Kasım, Aralık and Ocak, for simplicity. From 1918 the fiscal year has commenced on 1 January. In the Ottoman Empire, the lunar-based Hijri calendar remained in use for religious matters alongside the Rumi calendar. In order to prevent confusion between the dates, both calendars were used on most documents. To convert dates between the two calendars, the following periods have to be taken into consideration: Start-of-year correction Until the end of 1332 AH, Rumi dates in the last 12 or 13 days of December, all of January, February belong to the following Gregorian year.
Until the end of February 1917 AD, Gregorian dates in January and the first 12 or 13 days of March belong to the previous Rumi year. Before March 13, 1840 AD No conversion is possible. Between March 13, 1840 AD and March 13, 1900 AD Add 12 days and 584 years to find the Gregorian date. 1900 was not a Gregorian leap year. The day after February 28, 1900 AD was March 1, 1900 AD Between March 14, 1900 AD and February 28, 1917 AD Add 13 days and 584 years to find Gregorian date. Starting on March 1, 1917 AD Add 584 years only. From Rumi calendar into Gregorian calendar 31 March Incident occurred on March 31, 1325 AH Adding 13 days to date and 584 to year: April 13, 1909 AD From Gregorian calendar into Rumi calendar Proclamation of the republic in Turkey on October 29, 1923 AD Subtract 584 from year. Date remains same after January 1, 1918, due to use of the Gregorian calendar in the Rumi calendar: October 29, 1339 AH List of calendars Arabic names of calendar months Interconvert Gregorian and Rumi dates
In ancient Rome, the fasti were chronological or calendar-based lists, or other diachronic records or plans of official and religiously sanctioned events. After Rome's decline, the word fasti continued to be used for similar records in Christian Europe and Western culture. Public business, including the official business of the Roman state, had to be transacted on dies fasti, "allowed days"; the fasti were the records of this business. In addition to the word's general sense, there were fasti that recorded specific kinds of events, such as the fasti triumphales, lists of triumphs celebrated by Roman generals; the divisions of time used in the fasti were based on the Roman calendar. The yearly records of the fasti encouraged the writing of history in the form of chronological annales, "annals," which in turn influenced the development of Roman historiography. Fasti is the plural of the Latin adjective fastus, most used as a substantive; the word derives from fas, meaning "that, permitted," that is, "that, legitimate in the eyes of the gods."
Fasti dies were the days on which business might be transacted without impiety, in contrast to dies nefasti, days on which assemblies and courts could not convene. The word fasti; the temporal structure distinguished fasti from regesta, which were simple lists of property, or assets, such as land or documents, or transactions transferring property. Fasti Magistrales, Annales or Historici, were concerned with the several festivals, everything relating to religious practice and the gods, the magistrates, they came to be denominated magni, "great," by way of distinction from the bare calendar, or fasti diurni. The word fasti thus came to be used in the general sense of annals or historical records. Fasti consulares were official chronicles in which years were denoted by the respective consuls and other magistrates with the principal events that happened during their consulates, but sometimes not. An example is the fasti Capitolini, a modern name assigned because they were deposited in 1547 in the courtyard of the Palazzo dei Conservatori on the Capitoline Hill on order of Alessandro Farnese, who kept them temporarily in his villa after their excavation from the Roman forum in 1545 or 1546.
Michelangelo, who designed the complex of three palaces on the hill restored the tables of the fasti. The Palazzo today is one of the Capitoline Museums, which serve a double duty as museums and city government buildings; the fasti are located in the same room as the bronze wolf. More pieces discovered; the fasti consulares were discovered as 30 marble fragments in the forum. With them were 26 fragments of Acta Triumpharum, since called the fasti triumphales. Both lists were restored as distinct records; the restoration was based nearly on the observations of Onofrio Panvinio and Pirro Ligorio, who were standing at the top of the trench in which a portion of wall was showing, featuring inscriptional material between pilasters. They conferred with Michelangelo. Pope Paul III had authorized the mining of stone for St. Peter's in 1540 and Michelangelo was in fact protestingly working on its design also; the pope was following the widespread convention that prevailed in the Renaissance of ripping up the structures of the past to reuse in building structures they considered more magnificent.
The scholars were collaborating to save. A resident colony of quarrymen went on dismantling buildings. All trace of structures in that part of the forum vanished between August 15 and September 14, 1546; the stone was sold to lime burners for the creation of cement. None of these proceedings were in any way archaeological. Cardinal Farnese assigned the scholars to watch the diggings. Collecting a team they moved swiftly to rescue what they could, sinking tunnels to the side to search for fragments. Subsequently, more fragments turned up embedded in buildings in use, showing that the area had been less intensely mined and casting doubt of the location of the original source of the fragments, it has been estimated that the consular lists were in four entablatures several feet high: I covering AUC 1-364. They were not published, however, as two lists; the editors took certain freedoms, such as filling in missing magistrates from other records as they thought best and filling in missing dates AUC to give the appearance of a continuous yearly chronicle, at the same time concealing the problems.
Representations under the name capitolini are not that. There were in fact two different original lists placed under that name to which were added fragments found in 1816-1818, 1872–1878 and a final one from the Tiber river in 1888, unrestored. All the fragments became CIL I under Fragmenta Quae Dicuntur Capitolini, "Fragments Called Capitolini" and Cetera Quae Supersunt Fragmenta, "Other Remaining Fragments." The unified list states the magistrates for each AUC from the first year of the first king to the death of Augustus. The marble entablatures were erected at the order of Augustus, based on information available to the Romans although the nature and validity of this information remains unknown; the degree of detail suggest