An eclipse is an astronomical event that occurs when an astronomical object or spacecraft is temporarily obscured, 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 also used when a spacecraft reaches a position where it can observe two celestial bodies so aligned. An eclipse is the result of either an occultation or a transit.
The full moon is the lunar phase when the Moon appears fully illuminated from Earth's perspective. This occurs when Earth is located between the Sun and the Moon. This means that the lunar hemisphere facing Earth – the near side – is completely sunlit and appears as a circular disk. The full moon occurs roughly once a month.
The lunar phase or Moon phase is the shape of the Moon's directly sunlit portion as viewed from Earth. The lunar phases gradually change over a synodic month as the Moon's orbital positions around Earth and Earth around the Sun shift. The visible side of the moon is variously sunlit, depending on the position of the Moon in its orbit. Thus, this face's sunlit portion can vary from 0% to 100% . Each of the four "intermediate" lunar phases is approximately 7.4 days, with +/- 19 hours in variation due to the Moon's orbit's elliptical shape.
In astronomy, the new moon is the first lunar phase, when the Moon and Sun have the same ecliptic longitude. At this phase, the lunar disk is not visible to the unaided eye, but its presence may be detected because it occults stars behind it.
Eclipses may occur repeatedly, separated by certain intervals of time: these intervals are called eclipse cycles. The series of eclipses separated by a repeat of one of these intervals is called an eclipse series.
The saros is a period of exactly 223 synodic months, approximately 6585.3211 days, or 18 years, 10, 11, or 12 days, and 8 hours, that can be used to predict eclipses of the Sun and Moon. One saros period after an eclipse, the Sun, Earth, and Moon return to approximately the same relative geometry, a near straight line, and a nearly identical eclipse will occur, in what is referred to as an eclipse cycle. A sar is one half of a saros.
The heliacal rising or star rise of a star occurs annually, or the similar phenomenon of a planet, when it first becomes visible above the eastern horizon at dawn just before sunrise, after it has spent a season behind the sun rendering it invisible. Historically, the most important such rising is that of Sirius, which was an important feature of the Egyptian calendar and astronomical development. The rising of the Pleiades heralded the start of the Ancient Greek sailing season, using celestial navigation.
A lunar day is the period of time for Earth's Moon to complete one rotation on its axis with respect to the Sun. Due to tidal locking, it is the time the Moon takes to complete one orbit around Earth plus about 2.2 more Earth days to return to the same Moon phase. The lunar day is roughly 29 1/2 Earth days, the length of a lunar month, the time of which includes a full day-night cycle.
The Hindu calendar, Panchanga or Panjika is one of various lunisolar calendars that are traditionally used in the Indian subcontinent and Southeast Asia, with further regional variations for social and Hindu religious purposes. They adopt a similar underlying concept for timekeeping based on sidereal year for solar cycle and adjustment of lunar cycles in every three years, but differ in their relative emphasis to moon cycle or the sun cycle and the names of months and when they consider the New Year to start. Of the various regional calendars, the most studied and known Hindu calendars are the Shalivahana Shaka found in the Deccan region of Southern India, Vikram Samvat (Bikrami) found in Nepal, North and Central regions of India – all of which emphasize the lunar cycle. Their new year starts in spring. In regions such as Tamil Nadu and Kerala, the solar cycle is emphasized and this is called the Tamil Calendar and Malayalam calendar and these have origins in the second half of the 1st millennium CE. A Hindu calendar is sometimes referred to as Panchangam (पञ्चाङ्ग), which is known also known as Panjika in Eastern India.
In classical antiquity, the seven classical planets or seven luminaries are the seven moving astronomical objects in the sky visible to the naked eye: the Moon, Mercury, Venus, the Sun, Mars, Jupiter, and Saturn. The word planet comes from two related Greek words, πλάνης planēs and πλανήτης planētēs, both with the original meaning of "wanderer", expressing the fact that these objects move across the celestial sphere relative to the fixed stars. Greek astronomers such as Geminus and Ptolemy often divided the seven planets into the Sun, the Moon, and the five planets.
The Tibetan calendar, or Tibetan lunar calendar, is a lunisolar calendar, that is, the Tibetan year is composed of either 12 or 13 lunar months, each beginning and ending with a new moon. A thirteenth month is added every two or three years, so that an average Tibetan year is equal to the solar year.
Vikram Samvat or Bikram Sambat and also known as the Vikrami calendar, is the historical Hindu calendar used in the Indian subcontinent. It is the official calendar of Nepal. In India, it is used in several states. The traditional Vikram Samvat calendar, as used in India, uses lunar months and solar sidereal years. The Nepali Bikram Sambat introduced in 1901 AD, also uses a solar sidereal year.
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 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.
The Vira Nirvana Samvat (era) is a calendar era beginning on 7 October 527 BCE. It commemorates the Nirvana of Lord Mahaviraswami, the 24th Jain Tirthankara. This is one of the oldest system of chronological reckoning which is still used in India.
Ēkādaśī ("Eleventh"), also spelled as Ēkādaśi, is the eleventh lunar day (tithi) of each of the two lunar phases which occur in an vedic calendar month - the Shukla Pakṣa and the Kṛṣṇa Pakṣa It is according to the Vedic medical texts of Ayurveda and is mentioned in detail in many original treatises such as Charaka Samhita and Susruta Samhita.
Paksha , thwa and gа̄ in Nepal Bhasa, refers to a fortnight or a lunar phase in a month of the Hindu lunar calendar.
A total lunar eclipse took place at the Moon's descending node of the orbit on Tuesday, May 24, 1910 with an umbral eclipse magnitude of 1.09503. A total lunar eclipse takes place when the Earth comes between the Sun and the Moon and its shadow covers the Moon. Eclipse watchers can see the Moon turn red when the eclipse reaches totality. Total eclipses of the Moon happen at Full Moon when the Sun, Earth, and Moon are aligned to form a line. The astronomical term for this type of alignment is syzygy, which comes from the Greek word for being paired together. The Moon does not have its own light but shines because its surface reflects the Sun's rays. During a total lunar eclipse, the Earth comes between the Sun and the Moon and blocks any direct sunlight from reaching the Moon. The Sun casts the Earth's shadow on the Moon's surface. A shallow total eclipse saw the Moon in relative darkness for 49 minutes and 29.5 seconds. The Moon was 9.503% of its diameter into the Earth's umbral shadow, and should have been significantly darkened. The partial eclipse lasted for 3 hours, 35 minutes and 22.9 seconds in total.
Pūrṇimā is the word for full moon in Sanskrit. The day of Purnima is the day (Tithi) in each month when the full moon occurs, and marks the division in each month between the two lunar fortnights (paksha), and the Moon is aligned exactly in a straight line, called a syzygy, with the Sun and Earth. Full moon is considered the third of the four primary phases of the Moon; the other three phases are new moon, first quarter moon, and third quarter moon. The full moon shows 100% illumination, causes high tides, and can concur with lunar eclipses.
In lunar calendars, a lunar month is the time between two successive syzygies of the same type: new moons or full moons. The precise definition varies, especially for the beginning of the month.
The Hindu calendar is based on a geocentric model of the solar system. A geocentric model describes the solar system as seen by an observer on the surface of the earth.
