21 relations: A-type main-sequence star, Astronomical unit, Bright Star Catalogue, Brown dwarf, Constellation, Delphinus, Durchmusterung, Effective temperature, Epoch (astronomy), Henry Draper Catalogue, Hipparcos, Jupiter, Kelvin, Light-year, Minute and second of arc, Parsec, Smithsonian Astrophysical Observatory Star Catalog, Spacecraft, Star, Stellar classification, Stellar parallax.
An A-type main-sequence star (A V) or A dwarf star is a main-sequence (hydrogen-burning) star of spectral type A and luminosity class V. These stars have spectra which are defined by strong hydrogen Balmer absorption lines.
The astronomical unit (symbol: au, ua, or AU) is a unit of length, roughly the distance from Earth to the Sun.
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.
Brown dwarfs are substellar objects that occupy the mass range between the heaviest gas giant planets and the lightest stars, having masses between approximately 13 to 75–80 times that of Jupiter, or approximately to about.
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.
Delphinus (Eng. U.S.) Eng.
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.
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.
Jupiter is the fifth planet from the Sun and the largest in the Solar System.
The Kelvin scale is an absolute thermodynamic temperature scale using as its null point absolute zero, the temperature at which all thermal motion ceases in the classical description of thermodynamics.
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 parsec (symbol: pc) is a unit of length used to measure large distances to astronomical objects outside the Solar System.
The Smithsonian Astrophysical Observatory Star Catalog is an astrometric star catalogue.
A spacecraft is a vehicle or machine designed to fly in outer space.
A star is type of astronomical object consisting of a luminous spheroid of plasma held together by its own gravity.
In astronomy, stellar classification is the classification of stars based on their spectral characteristics.
Stellar parallax is the apparent shift of position of any nearby star (or other object) against the background of distant objects.
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.