In astronomy, an epoch or reference epoch is a moment in time used as a reference point for some time-varying astronomical quantity. It is useful for the...

and periodization, an epoch or reference epoch is an instant in time chosen as the origin of a particular calendar era. The "epoch" serves as a reference...

to: Any historical era Epoch (astronomy), a moment in time used as a reference for the orbital elements of a celestial body Epoch (computing), a moment...

definition of the light-year as a unit of measurement of distance. In astronomy, an epoch specifies a precise moment in time. The positions of celestial objects...

transform Bessel window, in signal processing Besselian date, see Epoch (astronomy)#Besselian years MV Bessel, a German merchant ship in service 1928–45...

Decimal time Epoch (astronomy) Epoch (reference date) Era J2000 – the epoch that starts on JD 2451545.0 (TT), the standard epoch used in astronomy since 1984...

In astronomy, an equinox is either of two places on the celestial sphere at which the ecliptic intersects the celestial equator. Although there are two...

The first picosecond (10−12 seconds) of cosmic time includes the Planck epoch, during which currently established laws of physics may not have applied;...

In cosmology, recombination refers to the epoch during which charged electrons and protons first became bound to form electrically neutral hydrogen atoms...

Almanac The Astronomical Almanac (new name) Ephemera Ephemeris time Epoch (astronomy) Epoch (reference date) Fundamental ephemeris January 0 or March 0 Keplerian...

502°/d · t where t is the time (in days) since January 1, 2000 (see Epoch (astronomy)). This shows that the smallest perigee occurs at either new moon or...

"The epoch of the constellations on the Farnese Atlas and their origin in Hipparchus's lost catalogue" (PDF). Journal for the History of Astronomy. 36/2...

clock Clock synchronization Clock signal Epoch (astronomy) Frequency standard Radio clock Time in astronomy Time signal Time metrology Time transfer Timekeeping...

the photon epoch was the period in the evolution of the early universe in which photons dominated the energy of the universe. The photon epoch started after...

Amateur astronomy is a hobby where participants enjoy observing or imaging celestial objects in the sky using the unaided eye, binoculars, or telescopes...

Indian astronomy refers to astronomy practiced in the Indian subcontinent. It has a long history stretching from pre-historic to modern times. Some of...

In computing, an epoch is a fixed date and time used as a reference from which a computer measures system time. Most computer systems determine time as...

Animation of barycenters In astronomy, the barycenter (or barycentre; from Ancient Greek βαρύς (barús) 'heavy' and κέντρον (kéntron) 'center') is the...

navigation Diurnal motion Eclipse Ecliptic Elongation Epoch Equinox Halley, Edmond History of Astronomy Jyotish Kepler's laws of planetary motion Occultation...

the Big Bang (13.799 ± 0.021 billion years ago) to the present day. An epoch is a moment in time from which nature or situations change to such a degree...

Bahadurkhani (1838) — by Ghulam Hussain Jaunpuri (1760–1862) Astrometry Epoch (astronomy) Ephemeris Star catalogue Kennedy, Edward Stewart (1956). Islamic Astronomical...

helium also experienced a similar reionization phase change, but at a later epoch in the history of the universe. This is usually called "helium reionization"...

In physical cosmology, the inflationary epoch was the period in the evolution of the early universe when, according to inflation theory, the universe...

Lower Imbrian epoch, while the eastern mare material is of the Upper Imbrian epoch, and the western mare material is of the Eratosthenian epoch.[citation...

short periods of time known as the quark epoch, the hadron epoch, and the lepton epoch. Together, these epochs encompassed less than 10 seconds of time...

scheme, placing its first year near the beginning of the Holocene geological epoch and the Neolithic Revolution, when humans shifted from a hunter-gatherer...

In physical cosmology, the quark epoch was the period in the evolution of the early universe when the fundamental interactions of gravitation, electromagnetism...

This is a compilation of symbols commonly used in astronomy, particularly professional astronomy. τ - age Astrometry parameters Rv - radial velocity cz...

2002). "The latitude and epoch for the formation of the southern Greek constellations". Journal for the History of Astronomy. 33 (113): 313–350. Bibcode:2002JHA...

is any model concerning the origin of the cosmos or the universe. In astronomy, cosmogony is the study of the origin of particular astrophysical objects...