Beta Pegasi (β Peg / β Pegasi) is a star in the constellation Pegasus. It also has the traditional name Scheat; confusingly, this name is also sometimes used for Delta Aquarii. In astronomy, an epoch is a moment in time for which celestial coordinates or orbital elements are specified. ... A Julian epoch is an epoch that is based on Julian years of exactly 365. ... This article is about the year 2000. ... Most stars are of nearly constant luminosity. ... In astronomy, stellar classification is a classification of stars based initially on photospheric temperature and its associated spectral characteristics, and subsequenly refined in terms of other characteristics. ... Right ascension (RA; symbol α: Greek letter alpha) is the astronomical term for one of the two coordinates of a point on the celestial sphere when using the equatorial coordinate system. ... In astronomy declination (dec) is one of the two coordinates of the equatorial coordinate system, the other being either right ascension or hour angle. ... A light year, abbreviated ly, is the distance light travels in one year: roughly 9. ... The parsec (symbol pc) is a unit of length used in astronomy. ... The apparent magnitude (m) of a star, planet or other heavenly body is a measure of its apparent brightness; that is, the amount of light received from the object. ... In astronomy, the solar mass is a unit of mass used to express the mass of stars and larger objects such as galaxies. ... In astronomy, the solar radius is a unit of length used to express the size of stars and larger objects such as galaxies. ... In astronomy, absolute magnitude is the apparent magnitude, m, an object would have if it were at a standardized distance away. ... // In General Physics In general physics, luminosity (more properly called luminance) is the density of luminous intensity in a given direction. ... The solar luminosity is a unit of luminosity (power emitted in the form of photons) conventionally used by astronomers to give the luminosities of stars. ... The historical temperature record shows the fluctuations of the temperature of the atmosphere and the oceans throughout history, and in particular since 1850. ... The kelvin (symbol: K) is the SI unit of temperature, and is one of the seven SI base units. ... The Pleiades star cluster A star is any massive gaseous body in outer space. ... Orion is a remarkable constellation, visible from most places on the globe (but not always the whole year long). ... Pegasus is a northern constellation, named after the mythological Pegasus. ... Skat is the name of Delta Aquarii. ...

Scheat is unusual among other bright stars in having such a relatively cool surface temperature in relation to other stars such as the Sun, although this is due in large part to its size, being a red giant. Scheat is also an irregular variable star, its brightness changing slowly over an irregular period. By ancient tradition, the Sun is the light in the heavens whose presence is day and whose absence is night. ... According to the Hertzsprung-Russell diagram, a red giant is a large non-main sequence star of stellar classification K or M; so-named because of the reddish appearance of the cooler giants. Examples include Aldebaran and Arcturus. ...