41 relations: Angular distance, Apparent magnitude, Astronomy & Astrophysics, Bortle scale, Bright Star Catalogue, BY Draconis variable, Calcium hydride, Cetus, Constellation, CSIRO, Debris disk, Double star, Durchmusterung, Effective temperature, Flamsteed designation, G-type main-sequence star, Gauss (unit), Gliese Catalogue of Nearby Stars, Glossary of astronomy, Henry Draper Catalogue, Hipparcos, Hyades (star cluster), Light-year, Minute and second of arc, Photosphere, Proper motion, SIMBAD, Smithsonian Astrophysical Observatory Star Catalog, Solar analog, Spectral line, Starspot, Stellar atmosphere, Stellar classification, Stellar kinematics, Stellar magnetic field, Stellar nucleosynthesis, Stellar population, Sun, Titanium oxide, Variable star, Variable star designation.
In mathematics (in particular geometry and trigonometry) and all natural sciences (e.g. astronomy and geophysics), the angular distance (angular separation, apparent distance, or apparent separation) between two point objects, as viewed from a location different from either of these objects, is the angle of length between the two directions originating from the observer and pointing toward these two objects.
The apparent magnitude of a celestial object is a number that is a measure of its brightness as seen by an observer on Earth.
Astronomy & Astrophysics is a peer-reviewed scientific journal covering theoretical, observational, and instrumental astronomy and astrophysics.
The Bortle scale is a nine-level numeric scale that measures the night sky's brightness of a particular location.
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.
BY Draconis variables are variable stars of late spectral types, usually K or M, and typically belong to the main sequence.
Calcium hydride is the chemical compound with the formula CaH2, and is therefore an alkaline earth hydride.
Cetus is a constellation.
Christmas is an annual festival commemorating the birth of Jesus Christ,Martindale, Cyril Charles.
The Christmas season, also called the festive season, or the holiday season (mainly in the U.S. and Canada; often simply called the holidays),, is an annually recurring period recognized in many Western and Western-influenced countries that is generally considered to run from late November to early January.
Christmas Eve is the evening or entire day before Christmas Day, the festival commemorating the birth of Jesus.
Christmas traditions vary from country to country.
A constellation is a group of stars that are considered to form imaginary outlines or meaningful patterns on the celestial sphere, typically representing animals, mythological people or gods, mythological creatures, or manufactured devices.
The Commonwealth Scientific and Industrial Research Organisation (CSIRO) is an independent Australian federal government agency responsible for scientific research.
A debris disk is a circumstellar disk of dust and debris in orbit around a star.
In observational astronomy, a double star or visual double is a pair of stars that appear close to each other in the sky as seen from Earth when viewed through an optical telescope.
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.
The effective temperature of a body such as a star or planet is the temperature of a black body that would emit the same total amount of electromagnetic radiation.
A Flamsteed designation is a combination of a number and constellation name that uniquely identifies most naked eye stars in the modern constellations visible from southern England.
A G-type main-sequence star (Spectral type: G-V), often (and imprecisely) called a yellow dwarf, or G dwarf star, is a main-sequence star (luminosity class V) of spectral type G. Such a star has about 0.84 to 1.15 solar masses and surface temperature of between 5,300 and 6,000 K., G. M. H. J. Habets and J. R. W. Heintze, Astronomy and Astrophysics Supplement 46 (November 1981), pp.
The gauss, abbreviated as G or Gs, is the cgs unit of measurement of magnetic flux density (or "magnetic induction") (B).
The Gliese Catalogue of Nearby Stars is a modern star catalogue of stars located within 25 parsecs (81.54 ly) of the Earth.
This page is a glossary of astronomy.
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.
The Hyades (Greek Ὑάδες, also known as Melotte 25 or Collinder 50) is the nearest open cluster and one of the best-studied star clusters.
The light-year is a unit of length used to express astronomical distances and measures about 9.5 trillion kilometres or 5.9 trillion miles.
A minute of arc, arcminute (arcmin), arc minute, or minute arc is a unit of angular measurement equal to of one degree.
New Year is the time or day at which a new calendar year begins and the calendar's year count increments by one.
New Year's Day, also called simply New Year's or New Year, is observed on January 1, the first day of the year on the modern Gregorian calendar as well as the Julian calendar.
In the Gregorian calendar, New Year's Eve (also known as Old Year's Day or Saint Sylvester's Day in many countries), the last day of the year, is on 31 December which is the seventh day of Christmastide.
The photosphere is a star's outer shell from which light is radiated.
Proper motion is the astronomical measure of the observed changes in the apparent places of stars or other celestial objects in the sky, as seen from the center of mass of the Solar System, compared to the abstract background of the more distant stars.
SIMBAD (the Set of Identifications, Measurements, and Bibliography for Astronomical Data) is an astronomical database of objects beyond the Solar System.
The Smithsonian Astrophysical Observatory Star Catalog is an astrometric star catalogue.
Solar-type star, solar analogs (also analogues), and solar twins are stars that are particularly similar to the Sun.
A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from emission or absorption of light in a narrow frequency range, compared with the nearby frequencies.
Starspots are stellar phenomena.
The stellar atmosphere is the outer region of the volume of a star, lying above the stellar core, radiation zone and convection zone.
In astronomy, stellar classification is the classification of stars based on their spectral characteristics.
In astronomy, stellar kinematics is the observational study or measurement of the kinematics or motions of stars through space.
A stellar magnetic field is a magnetic field generated by the motion of conductive plasma inside a star.
Stellar nucleosynthesis is the theory explaining the creation (nucleosynthesis) of chemical elements by nuclear fusion reactions between atoms within the stars.
During 1944, Walter Baade categorized groups of stars within the Milky Way into bluer stars associated with the spiral arms and the general position of yellow stars near the central galactic bulge or within globular star clusters.
The Sun is the star at the center of the Solar System.
Titanium oxide may refer to.
A variable star is a star whose brightness as seen from Earth (its apparent magnitude) fluctuates.
Variable stars are designated using a variation on the Bayer designation format of an identifying label (as described below) combined with the Latin genitive of the name of the constellation in which the star lies.
2018 has been designated as the third International Year of the Reef by the International Coral Reef Initiative.
2019 (MMXIX) will be a common year starting on Tuesday of the Gregorian calendar, the 2019th year of the Common Era (CE) and Anno Domini (AD) designations, the 19th year of the 3rd millennium, the 19th year of the 21st century, and the 10th and last year of the 2010s decade.