List of stars more luminous than any closer star

In order to find a star more luminous than α Cen, the radius would have to be extended out to 9 light years, to include Sirius. The closest star more luminous than Sirius is Vega, at 25 light years, and so on. List of most luminous stars. List of nearest stars. List of nearest bright stars.

Extraterrestrial places in the Cthulhu Mythos

Xoth may be the star Sirius, since "Xoth" is similar to "Sothis", the Egyptian name for the star. However, it is more likely that Xoth coincides with the star "Zoth" in Smith's writings. Yaddith is a distant planet that orbits five suns, and itself orbited by five moons. Yaddith is located thousands of light years from the Sun, near the star Deneb. Aeons ago, it was inhabited by the Nug-Soth, creatures with traits similar to mammals, reptiles, and insects. The Nug-Soth sought a way to prevent the destruction of their planet's crust by the Dholes, but to no avail. Eventually, the Dholes overwhelmed them and destroyed the Nug-Soth's civilization.

Orders of magnitude (length)

To help compare different distances this section lists lengths starting at 10 10 metres (10 gigametres (Gm) or 10 million kilometres, or 0.07 Astronomical units). To help compare distances at different orders of magnitude this section lists lengths starting at 10 11 metres (100 Gm or 100 million kilometres or 0.7 astronomical units). To help compare different distances, this section lists lengths starting at 10 12 m (1 Tm or 1 billion km or 6.7 astronomical units). To help compare different distances this section lists lengths starting at 10 13 m (10 Tm or 10 billion km or 67 astronomical units).

Béla Harkányi

Kobold), occasionally visiting major astronomical institutes in Germany and the USA, including Lick Observatory. He obtained his PhD in 1896 at the Royal Hungarian University of Sciences in Budapest. Next he spent two years at the Observatory of Paris with postgraduate studies, attending, among others, Poincaré's university lectures. In the first half of 1899 he worked in the Observatory of Potsdam under J. F. Hartmann, following which he started work in the astronomical observatory of Miklós Konkoly-Thege in Ógyalla. Here he conducted observational photometry while he also developed an interest in theoretical astrophysics, under the influence of his friend and associate, Radó Kövesligethy.

Winter Triangle

The Winter Triangle is an astronomical asterism formed from three of the brightest stars in the winter sky. It is an imaginary equilateral triangle drawn on the celestial sphere, with its defining vertices at Sirius, Betelgeuse, and Procyon, the primary stars in the three constellations of Canis Major, Orion, and Canis Minor, respectively. For much of the night in the northern winter, the Winter Triangle lies high in the sky at mid-northern latitudes, but can also be seen during autumn in the early morning to the East. In the spring the winter triangle is visible early in the evening to the West before its stars set below the horizon.

List of nearest stars and brown dwarfs

passing starsnearest starsclosest stars
There are 52 stellar systems beyond our own Solar system that currently lie within 5.0 pc of the Sun. These systems contain a total of 63 stars, of which 50 are red dwarfs, by far the most common type of star in the Milky Way. Much more massive stars, such as our own, make up the remaining 13. In addition to these "true" stars, there are 11 brown dwarfs (objects not quite massive enough to fuse hydrogen), and 4 white dwarfs (extremely dense objects that remain after stars such as our Sun exhaust all fusable hydrogen in their core and slowly shed their outer layers while only the collapsed core remains).

List of largest stars

largest known starslargest stars knownlargest stars
Jupiter < Proxima Centauri < Sun < Sirius A 4. Sirius A < Pollux < Arcturus < Aldebaran 5. Aldebaran < Rigel A < Antares A < Betelgeuse 6. Betelgeuse < Mu Cephei < VV Cephei A < VY Canis Majoris Below is an ordered list of the largest stars currently known by radius. The unit of measurement used is the radius of the Sun (approximately 1 solar radius). The exact order of this list is very incomplete, as great uncertainties currently remain, especially when deriving various important parameters used in calculations, such as stellar luminosity and effective temperature. Often stellar radii can only be expressed as an average or within a large range of values.

Big Dipper

Northern DipperPloughBeidou
Extending a line from Phecda to Megrez leads to Thuban (α Draconis), which was the pole star 4,000 years ago. Crossing the top of the bowl from Megrez to Dubhe takes one in the direction of Capella (α Aurigae). A mnemonic for this is "Cap to Capella.". Castor (α Geminorum) is reached by imagining a diagonal line from Megrez to Merak and then extending it for approximately five times that distance. By following the curve of the handle from Alioth to Mizar to Alkaid, one reaches Arcturus (α Boötis) and Spica (α Virginis). A mnemonic for this is "Arc to Arcturus then speed (or spike) to Spica.".

VY Canis Majoris

This demonstrates that LBVs, such as Eta Carinae, are not the only progenitors of SNe IIn or HN, but it stressed the requirement that these types of supernovae increased episodic mass loss just prior to the explosion. For a star as massive as VY CMa, the remnant would be likely a black hole rather than a neutron star. * Remote Sensing Tutorial Page A-5 archive VLT image of the surroundings of VY Canis Majoris seen with SPHERE Astronomers Map a Hypergiant Star's Massive Outbursts, HubbleSite NewsCenter, 2007-01-08. "What is the Biggest Star in the Universe?", Fraser Cain, Universe Today, published 2008-04-06, updated 13 May 2013.


lunarthe MoonLuna
Understanding of the Moon's cycles was an early development of astronomy: by the 5th century BC, Babylonian astronomers had recorded the 18-year Saros cycle of lunar eclipses, and Indian astronomers had described the Moon's monthly elongation. The Chinese astronomer Shi Shen (fl. 4th century BC) gave instructions for predicting solar and lunar eclipses. Later, the physical form of the Moon and the cause of moonlight became understood. The ancient Greek philosopher Anaxagoras (d. 428 BC) reasoned that the Sun and Moon were both giant spherical rocks, and that the latter reflected the light of the former.

Observational astronomy

astronomical observationobservationsobservational
The darkness of the night sky is an important factor in optical astronomy. With the size of cities and human populated areas ever expanding, the amount of artificial light at night has also increased. These artificial lights produce a diffuse background illumination that makes observation of faint astronomical features very difficult without special filters. In a few locations such as the state of Arizona and in the United Kingdom, this has led to campaigns for the reduction of light pollution. The use of hoods around street lights not only improves the amount of light directed toward the ground, but also helps reduce the light directed toward the sky.

Astronomical object

celestial bodiescelestial bodycelestial object
An astronomical object or celestial object is a naturally occurring physical entity, association, or structure that exists in the observable universe. In astronomy, the terms object and body are often used interchangeably. However, an astronomical body or celestial body is a single, tightly bound, contiguous entity, while an astronomical or celestial object is a complex, less cohesively bound structure, which may consist of multiple bodies or even other objects with substructures. Examples of astronomical objects include planetary systems, star clusters, nebulae, and galaxies, while asteroids, moons, planets, and stars are astronomical bodies.

White dwarf

white dwarfswhite dwarf starcentral star
Astronomy Picture of the Day. NGC 2440: Cocoon of a New White Dwarf 2010 February 21. Dust and the Helix Nebula 2009 December 31. The Helix Nebula from La Silla Observatory 2009 March 3. IC 4406: A Seemingly Square Nebula 2008 July 27. A Nearby Supernova in Spiral Galaxy M100 2006 March 7. Astronomy Picture of the Day: White Dwarf Star Spiral 2005 June 1.


The astrolabe was a marriage of the planisphere and dioptra, effectively an analog calculator capable of working out several different kinds of problems in astronomy. Theon of Alexandria (c. 335 – c. 405) wrote a detailed treatise on the astrolabe, and Lewis argues that Ptolemy used an astrolabe to make the astronomical observations recorded in the Tetrabiblos. The invention of the plane astrolabe is sometimes wrongly attributed to Theon's daughter Hypatia (c. undefined 350–370; died 415 AD), but it is, in fact, known to have already been in use at least 500 years before Hypatia was born.

John Flamsteed

FlamsteedFlamsteed, JohnSir John Flamsteed
He associated himself with local gentlemen interested in astronomy, including William Litchford, whose library included the work of the astrologer John Gadbury which included astronomical tables by Jeremiah Horrocks, who had died in 1641 at the age of twenty-two. Flamsteed was greatly impressed (as Isaac Newton had been) by the work of Horrocks. In August 1665, at the age of nineteen and as a gift for his friend Litchford, Flamsteed wrote his first paper on astronomy, entitled Mathematical Essays, concerning the design, use and construction of an astronomer's quadrant, including tables for the latitude of Derby.

Interstellar medium

interstellar gasinterstellarinterstellar matter
A great deal of radio astronomy depends on compensating for the different propagation effects to uncover the desired signal. The nature of the interstellar medium has received the attention of astronomers and scientists over the centuries, and understanding of the ISM has developed. However, they first had to acknowledge the basic concept of "interstellar" space. The term appears to have been first used in print by : "The Interstellar Skie.. hath .. so much Affinity with the Starre, that there is a Rotation of that, as well as of the Starre." Later, natural philosopher discussed "The inter-stellar part of heaven, which several of the modern Epicureans would have to be empty."

Cosmic dust

interstellar dustdustspace dust
Cosmic dust was once solely an annoyance to astronomers, as it obscures objects they wish to observe. When infrared astronomy began, the dust particles were observed to be significant and vital components of astrophysical processes. Their analysis can reveal information about phenomena like the formation of the Solar System. For example, cosmic dust can drive the mass loss when a star is nearing the end of its life, play a part in the early stages of star formation, and form planets. In the Solar System, dust plays a major role in the zodiacal light, Saturn's B Ring spokes, the outer diffuse planetary rings at Jupiter, Saturn, Uranus and Neptune, and comets.

Mount Wilson Observatory

Mount WilsonMt. WilsonHooker Telescope
In 1919 the Hooker telescope was equipped with a special attachment, a 6-meter optical astronomical interferometer developed by Albert A. Michelson, much larger than the one he had used to measure Jupiter's satellites. Michelson was able to use the equipment to determine the precise diameter of stars, such as Betelgeuse, the first time the size of a star had ever been measured. Henry Norris Russell developed his star classification system based on observations using the Hooker. In 1935 the silver coating used since 1917 on the Hooker mirror was replaced with a more modern and longer lasting aluminum coating that reflected 50% more light than the older silver method of coating.


BoorongBoorong peopleWotjobaluk
A reanalysis of Stanbridge's material has recently led to the hypothesis that the Wergaia had registered the massive flaring or 'great eruption' of η Carinae, which they identified as collowgullouric war (a female crow and wife of war (Canopus)), and did so sometimes after 1837, and had incorporated it into their ethnoastronomical system. A few examples illustrate the intimate correlation they established between the movements of celestial bodies and the cycles of natural phenomena in their native habitat. The northern rise of Arcturus, known as Marpeankuurk signaled that it was time to harvest the larvae of a species of Carpenter ant, the wood ant are ready to be harvested.


the Renaissanceearly RenaissanceRenaissance Europe
As the pioneer headquarters of European exploration, Lisbon flourished in the late 15th century, attracting experts who made several breakthroughs in mathematics, astronomy and naval technology, including Pedro Nunes, João de Castro, Abraham Zacuto and Martin Behaim. Cartographers Pedro Reinel, Lopo Homem, Estêvão Gomes and Diogo Ribeiro made crucial advances in mapping the world. Apothecary Tomé Pires and physicians Garcia de Orta and Cristóvão da Costa collected and published works on plants and medicines, soon translated by Flemish pioneer botanist Carolus Clusius.

Space telescope

space observatoryspace observatoriesAstronomy
Ultraviolet astronomy. X-ray astronomy satellite.


North Starpole starNorthern Star
Its name in traditional pre-Islamic Arab astronomy was Al-Judeyy الجدي, and that name was used in medieval Islamic astronomy as well. In those times, it was not yet as close to the north celestial pole as it is now, and used to rotate around the pole. It was invoked as a symbol of steadfastness in poetry, as "steadfast star" by Spenser. Shakespeare's sonnet 116 is an example of the symbolism of the north star as a guiding principle: "[Love] is the star to every wandering bark / Whose worth's unknown, although his height be taken."

William Herschel

HerschelWilliamSir William Herschel
In 1782, he was appointed "The King's Astronomer" (not to be confused with the Astronomer Royal). On 1 August 1782 Herschel and his sister Caroline moved to Datchet (then in Buckinghamshire but now in Berkshire). There he continued his work as an astronomer and telescope maker. He achieved an international reputation for their manufacture, profitably selling over 60 completed reflectors to British and Continental astronomers. From 1782 to 1802, and most intensively from 1783 to 1790, Herschel conducted systematic surveys in search of "deep sky" or nonstellar objects with two 20 foot, 12 inch and 18.7 inch telescopes (in combination with his favoured 6-inch aperture instrument).


In astronomy, metallicity is used to describe the abundance of elements present in an object that are heavier than hydrogen or helium. Most of the physical matter in the Universe is in the form of hydrogen and helium, so astronomers use the word "metals" as a convenient short term for "all elements except hydrogen and helium". This usage is distinct from the usual physical definition of a solid metal. For example, stars and nebulae with relatively high abundances of carbon, nitrogen, oxygen, and neon are called "metal-rich" in astrophysical terms, even though those elements are non-metals in chemistry.

Effective temperature

surface temperatureeffective (surface) temperaturetemperature
A red star could be a tiny red dwarf, a star of feeble energy production and a small surface or a bloated giant or even supergiant star such as Antares or Betelgeuse, either of which generates far greater energy but passes it through a surface so large that the star radiates little per unit of surface area. A star near the middle of the spectrum, such as the modest Sun or the giant Capella radiates more energy per unit of surface area than the feeble red dwarf stars or the bloated supergiants, but much less than such a white or blue star as Vega or Rigel.