Triangulum Australe

Southern TriangleTrATrianguli Australis
NGC 5979, a planetary nebula of apparent magnitude 12.3, has a blue-green hue at higher magnifications, while Henize 2-138 is a smaller planetary nebula of magnitude 11.0. NGC 5938 is a remote spiral galaxy around 300 million light-years (90 megaparsecs) away. It is located 5 degrees south of Epsilon Trianguli Australis. ESO 69-6 is a pair of merging galaxies located about 600 million light-years (185 megaparsecs) away. Their contents have been dragged out in long tails by the interaction. Citations Sources Online sources The Deep Photographic Guide to the Constellations: Triangulum Australe. Starry Night Photography: Triangulum Australe.

Delta Canis Majoris

δ CMaδ Canis MajorisDelta
It is a yellow-white F-type supergiant with an apparent magnitude of +1.83. Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified. Delta Canis Majoris is the third-brightest star in the constellation after Sirius and ε Canis Majoris (Adhara), with an apparent magnitude of +1.83, and is white or yellow-white in colour. Lying about 10 degrees south southeast of Sirius, it only rises to about 11 degrees above the horizon at the latitude of the United Kingdom. The open cluster NGC 2354 is located only 1.3 degrees east of Delta Canis Majoris.


This gigapixel camera or 'GPC' saw first light on August 22, 2007, imaging the Andromeda Galaxy. After initial technical difficulties that were later mostly solved, PS1 began full operation on May 13, 2010. Nick Kaiser, principal investigator of the Pan-STARRS project, summed it up saying “PS1 has been taking science-quality data for six months, but now we are doing it dusk-to-dawn every night.” (quote: June 15, 2010). The PS1 images however remain slightly less sharp than initially planned, which significantly affects some scientific uses of the data.

Timeline of the far future

far future40,000 years296,000 years
Orders of magnitude (time). Space and survival. 10th millennium. Timeline of natural history. Timeline of the formation of the Universe. Timeline of the near future. Ultimate fate of the universe.

Iota2 Normae

ι 2 Norι² Normae
It is faintly visible to the naked eye with an apparent visual magnitude of +5.57. Measuring its parallax reveals it is located 280 light-years away from the sun. At that distance, the visual magnitude is diminished by an interstellar extinction factor of 0.24 due to intervening dust. The radial velocity of this star is zero, indicating it is neither moving toward nor away from the Sun. Iota 2 Normae is a B-type main-sequence star with a stellar classification of B9.5 V. It is larger than the Sun with 2.6 times the mass of the Sun and about 3.1 times the Sun's radius. The star is estimated to be 257 million years old and is spinning with a projected rotational velocity of 111 km/s.

List of exoplanetary host stars

The following is a list of exoplanetary host stars. The table contains information about the coordinates, spectral and physical properties, and number of confirmed planets. The two most important stellar properties are mass and metallicity because they determine how these planetary systems form. Stars of higher mass and metallicity tend to have more numerous and more massive planets.

NGC 4565

NGC 4565 (also known as the Needle Galaxy or Caldwell 38) is an edge-on spiral galaxy about 30 to 50 million light-years away in the constellation Coma Berenices. It lies close to the North Galactic Pole and has a visual magnitude of approximately 10. It is known as the Needle Galaxy for its narrow profile. First recorded in 1785 by William Herschel, it is a prominent example of an edge-on spiral galaxy. NGC 4565 is a giant spiral galaxy more luminous than the Andromeda Galaxy. Much speculation exists in literature as to the nature of the central bulge.


Lyramong the starsConstellation of Orpheus
The true nova HR Lyrae flared in 1919 to a maximum magnitude of 6.5, over 9.5 magnitudes higher than in quiescence. Some of its characteristics are similar to those of recurring novae. M57, also known as the "Ring Nebula" and NGC 6720, has a diameter of one light-year and is at a distance of 2,000 light-years from Earth. It is one of the best known planetary nebulae and the second to be discovered; its integrated magnitude is 8.8. It was discovered in 1779 by Antoine Darquier, 15 years after Charles Messier discovered the Dumbbell Nebula. Astronomers have determined that it is between 6,000 and 8,000 years old; it is approximately one light-year in diameter.

List of star extremes

most extreme stars
A star is a sphere that is mainly composed of hydrogen and plasma, held together by gravity and is able to produce light through nuclear fusion. Stars exhibit many diverse properties, resulting from different masses, volumes, velocities, stage in stellar evolution and even proximity to earth. Some of these properties are considered extreme and sometimes disproportionate by astronomers.

Epsilon Eridani

ε Eridaniε EriEpsilon Erdani
The apparent magnitude of 3.73 can make it difficult to observe from an urban area with the unaided eye, because the night skies over cities are obscured by light pollution. Epsilon Eridani has an estimated mass of 0.82 solar masses and a radius of 0.74 solar radii. It shines with a luminosity of only 0.34 solar luminosities. The estimated effective temperature is 5,084 K. With a stellar classification of K2 V, it is the second-nearest K-type main-sequence star (after Alpha Centauri B). Since 1943 the spectrum of Epsilon Eridani has served as one of the stable anchor points by which other stars are classified.

NGC 7418

Galaxies like the Milky Way and the Andromeda Galaxy have been found to host both. The stellar population at the nucleus of NGC 7418 has been found to be quite young, with mean age less than 100 million years, indicating recent star forming activity. One supernova has been observed in NGC 7418, SN 1983 Z. It was discovered by L. E. Gonzalez at Cerro El Roble 11" west and 52" south of the nucleus. On September 3 1983 it had an apparent magnitude of 15.5. NGC 7418 is a member of a galaxy group known as the IC 1459 group. It is a loose group centred at IC 1459 and contains a large number of spiral galaxies.

List of red dwarfs

This is a list of the least intrinsically energetic, the least luminous (absolute magnitude) red dwarf stars This is a list of the least luminous (absolute magnitude) red dwarfs This is a list of the most intrinsically energetic, the most luminous (absolute magnitude) red dwarf stars This is a list of the most luminous (absolute magnitude) red dwarfs This is a list of the least bright (apparent magnitude) red dwarf stars, as they appear from Earth This is a list of titleholders of being the dimmest (apparent magnitude) red dwarf as seen from Earth, and its succession over time.

Stars and planetary systems in fiction

47 Ursae Majoris in fictionArcturus61 Cygni
Although the 61 Cygni binary is known to be the home system of Mesklin, and is often seen in the sky, it is never actually named in the book: 61 Cygni A is always called simply "the sun", while 61 Cygni B, fainter by a full apparent magnitude, bears the Mesklinite name Esstes. Andromeda: A Space Age Tale (1959), novel by Ivan Yefremov. The Earth of the far future is a communist utopia, nonetheless able to send no more than a few infrequent space ships to the nearest star systems, since interstellar travel is limited by the speed of light. One of these near neighbors is 61 Cygni, which has a planet and is also the 16th-closest star to the Sun.

Type Ia supernova

type Iatype 1a supernovatype Ia supernovae
The Chandra X-ray Observatory revealed that the X-ray radiation of five elliptical galaxies and the bulge of the Andromeda galaxy is 30–50 times fainter than expected. X-ray radiation should be emitted by the accretion discs of Type Ia supernova progenitors. The missing radiation indicates that few white dwarfs possess accretion discs, ruling out the common, accretion-based model of Ia supernovae. Inward spiraling white dwarf pairs are strongly-inferred candidate sources of gravitational waves, although they have not been directly observed.

List of astronomy acronyms

EGGsX-Ray Flashes
ACV – (celestial object) Alpha Canes Venatici, a class of rotating variable stars with strong magnetic fields named after Alpha Canum Venaticorum (Cor Caroli), the archetype for the class. ACYG – (celestial object) Alpha CYGni, a class of rotating variable stars named after Alpha Cygni (Deneb), the archetype for the class. ADAF – (astrophysics terminology) Advection Dominated Accretion Flow, a mechanism by which matter is slowly accreted onto a black hole. ADC – (organization) Astronomical Data Center. ADEC – (organization) Astrophysics Data Centers Executive Council, an organization that provides oversight for the Astrophysics Data and Information Services.

List of selected stars for navigation

navigational starsnavigation star58 stars
The final characteristic provided in the tables and star charts is the star's brightness, expressed in terms of apparent magnitude. Magnitude is a logarithmic scale of brightness, designed so that a body of one magnitude is approximately 2.512 times brighter than a body of the next magnitude. Thus, a body of magnitude 1 is 2.512 5, or 100 times brighter than a body of magnitude 6. The dimmest stars that can be seen through a 200 inch terrestrial telescope are of the 20th magnitude, and very bright objects like the Sun and a full Moon have magnitudes of −26.7 and −12.6 respectively. The table of navigational stars provides several types of information.

Norma (constellation)

NormaNorconstellation Norma
NGC 6087 is the brightest of the open clusters in Norma with a magnitude of 5.4. It lies in the southeastern corner of the constellation between Alpha Centauri and Zeta Arae. Thought to be around 100 million years old, it is about 3300 light-years away and is around 14 light-years in diameter. Its brightest member is the Cepheid variable S Normae. A rich background star field makes it less distinct, though around 36 member stars are visible though a 10 cm telescope at 150x magnification. Located 0.4° north of Kappa Normae is NGC 6067, which has an integrated magnitude of 5.6 though it is indistinct as it lies in a rich star field.

Cosmic distance ladder

standard candlestandard candlesdistance
The brightness of an object can be expressed in terms of its absolute magnitude. This quantity is derived from the logarithm of its luminosity as seen from a distance of 10 parsecs. The apparent magnitude, the magnitude as seen by the observer (an instrument called a bolometer is used), can be measured and used with the absolute magnitude to calculate the distance D to the object in kiloparsecs (where 1 kpc equals 1000 parsecs) as follows: or where m is the apparent magnitude and M the absolute magnitude. For this to be accurate, both magnitudes must be in the same frequency band and there can be no relative motion in the radial direction.


TriTriangulaTriangulum (constellation)
Within the constellation, it lies near the border of Pisces, 3.5 degrees west-northwest of Alpha Trianguli and 7 degrees southwest of Beta Andromedae. Within the galaxy, NGC 604 is an H II region where star formation takes place. In addition to M33, there are several NGC galaxies of visual magnitudes 12 to 14. The largest of these include the 10 arcminute long magnitude 12 NGC 925 spiral galaxy and the 5 arcminute long magnitude 11.6 NGC 672 barred spiral galaxy. The latter is close by and appears to be interacting with IC 1727. The two are 88,000 light-years apart and lie around 18 million light-years away.

C/2011 L4

Original estimates predicted that C/2011 L4 would brighten to roughly apparent magnitude 0 (roughly the brightness of Alpha Centauri A or Vega). An estimate in October 2012 predicted that it might brighten to magnitude −4 (roughly equivalent to Venus). In January 2013 there was a noticeable brightening slowdown that suggested that it may only brighten to magnitude +1. During February the brightness curve showed a further slowdown suggesting a perihelion magnitude of around +2. However, a study using the secular light curve indicates that C/2011 L4 had a "slowdown event" when it was 3.6 AU from the Sun at a magnitude 5.6.

Extraterrestrial skies

Mercurian daylunar skynight sky
From 40 Eridani, 16 light years away, the Sun would be an average looking star of about apparent magnitude 3.3 in the constellation Serpens Caput. At this distance most of the stars nearest to us would be in different locations to those in our sky, including Alpha Centauri, Sirius, and Procyon. From a planet orbiting Aldebaran, 65 light years away, our Sun would be seen as an insignificant 6.4 magnitude star between Ophiuchus and Scorpius (more specifically, it would in the vicinity of Phi Ophiuchi and 24 Scorpii). Constellations made of bright, distant stars would look somewhat similar (such as Orion and Scorpius) but much of the night sky would seem unfamiliar to someone from Earth.