11 relations: American Association of Variable Star Observers, Bright Star Catalogue, Cancer (constellation), Durchmusterung, Epoch (astronomy), Henry Draper Catalogue, Hipparcos, Luminosity, Semiregular variable star, Star, Variable star.
Since its founding in 1911, the American Association of Variable Star Observers (AAVSO) has coordinated, collected, evaluated, analyzed, published, and archived variable star observations made largely by amateur astronomers and makes the records available to professional astronomers, researchers, and educators.
The Bright Star Catalogue, also known as the Yale Catalogue of Bright Stars or Yale Bright Star Catalogue, is a star catalogue that lists all stars of stellar magnitude 6.5 or brighter, which is roughly every star visible to the naked eye from Earth.
Cancer is one of the twelve constellations of the zodiac.
In astronomy, Durchmusterung or Bonner Durchmusterung (BD), is the comprehensive astrometric star catalogue of the whole sky, compiled by the Bonn Observatory (Germany) from 1859 to 1903.
In astronomy, an epoch is a moment in time used as a reference point for some time-varying astronomical quantity, such as the celestial coordinates or elliptical orbital elements of a celestial body, because these are subject to perturbations and vary with time.
The Henry Draper Catalogue (HD) is an astronomical star catalogue published between 1918 and 1924, giving spectroscopic classifications for 225,300 stars; it was later expanded by the Henry Draper Extension (HDE), published between 1925 and 1936, which gave classifications for 46,850 more stars, and by the Henry Draper Extension Charts (HDEC), published from 1937 to 1949 in the form of charts, which gave classifications for 86,933 more stars.
Hipparcos was a scientific satellite of the European Space Agency (ESA), launched in 1989 and operated until 1993.
In astronomy, luminosity is the total amount of energy emitted per unit of time by a star, galaxy, or other astronomical object.
Semiregular variable stars are giants or supergiants of intermediate and late spectral type showing considerable periodicity in their light changes, accompanied or sometimes interrupted by various irregularities.
A star is type of astronomical object consisting of a luminous spheroid of plasma held together by its own gravity.
A variable star is a star whose brightness as seen from Earth (its apparent magnitude) fluctuates.