Apparent magnitudeApparent magnitude (m) is a measure of the brightness of a star, astronomical object or other celestial objects like artificial satellites. Its value depends on its intrinsic luminosity, its distance, and any extinction of the object's light caused by interstellar dust or atmosphere along the line of sight to the observer. Unless stated otherwise, the word magnitude in astronomy usually refers to a celestial object's apparent magnitude.
StarLarge self-illuminated object in spaceThe Sun, a G-type main-sequence star, the closest to EarthA star-forming region in the Large Magellanic CloudA star is a luminous spheroid of plasma held together by self-gravity. The nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night; their immense distances from Earth make them appear as fixedpoints of light.
List of brightest starsThis is a list of stars arranged by their apparent magnitude – their brightness as observed from Earth. It includes all stars brighter than magnitude +2.50 in visible light, measured using a V-band filter in the UBV photometric system. Stars in binary systems (or other multiples) are listed by their total or combined brightness if they appear as a single star to the naked eye, or listed separately if they do not.
Canis MinorCanis Minor is a small constellation in the northern celestial hemisphere. In the second century, it was included as an asterism, or pattern, of two stars in Ptolemy's 48 constellations, and it is counted among the 88 modern constellations. Its name is Latin for "lesser dog", in contrast to Canis Major, the "greater dog"; both figures are commonly represented as following the constellation of Orion the hunter.
Bayer designationA Bayer designation is a stellar designation in which a specific star is identified by a Greek or Latin letter followed by the genitive form of its parent constellation's Latin name. The original list of Bayer designations contained 1564 stars. The brighter stars were assigned their first systematic names by the German astronomer Johann Bayer in 1603, in his star atlas Uranometria.
Night skyThe night sky is the nighttime appearance of celestial objects like stars, planets, and the Moon, which are visible in a clear sky between sunset and sunrise, when the Sun is below the horizon. Natural light sources in a night sky include moonlight, starlight, and airglow, depending on location and timing. Aurorae light up the skies above the polar circles.
HipparcosHipparcos was a scientific satellite of the European Space Agency (ESA), launched in 1989 and operated until 1993. It was the first space experiment devoted to precision astrometry, the accurate measurement of the positions and distances of celestial objects on the sky. This was the first practical attempt at all-sky absolute parallax measurement, something not possible with groundside observatories, and thus represented a fundamental breakthrough in astronomy.
ParsecThe parsec (symbol: pc) is a unit of length used to measure the large distances to astronomical objects outside the Solar System, approximately equal to 3.26 light-years or 206,265 astronomical units (au), i.e., 30.9 trillionkilometres (19.2 trillion miles). The parsec unit is obtained by the use of parallax and trigonometry, and is defined as the distance at which 1 au subtends an angle of one arcsecond (1/3600 of a degree).
European Space AgencyEuropean organisation dedicated to space explorationThe European Space Agency (ESA; pronounced ) is a 23-member international organisation devoted to space exploration. It has its headquarters in Paris and a staff of around 3,000 people globally as of 2025. ESA was founded in 1975 in the context of European integration. Its 2026 annual budget was around €8.3 billion.
Latinisation of namesLatinisation (or Latinization) of names is the practice of changing certain non-Latin names into a form that more closely fits the style, structure, and rules of Latin. The practice is found with historical proper names, including personal names and toponyms, and in the standard binomial nomenclature of the life sciences.
ConstellationA constellation is an area on the celestial sphere in which a group of visible stars forms a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The first constellations were likely defined in prehistory. People used them to relate stories of their beliefs, experiences, creation, and mythology.
Light-yearA light-year, alternatively spelled light year (ly or lyr), is a unit of length used to express astronomical distances and is equal to exactly 9460730472580.8 km, which is approximately 9.46 trillion kilometres or 5.88 trillion miles. As defined by the International Astronomical Union (IAU), a light-year is the distance that light travels in vacuum in one Julian year (365.25 days). Despite its inclusion of the word "year", the term is a unit of distance, not a unit of time.*As an Amazon Associate I earn from qualifying purchases.