Apparent visual magnitude in the context of "Mesarthim"

Lambda Scorpii is a triple star system and the second-brightest object in the constellation of Scorpius. It is formally named Shaula; Lambda Scorpii is its Bayer designation, which is Latinised from λ Scorpii and abbreviated Lambda Sco or λ Sco. With an apparent visual magnitude of 1.63, it is one of the brightest stars in the night sky.

Beta Fornacis (Beta For, β Fornacis, β For) is solitary star in the southern constellation of Fornax. It is visible to the naked eye with an apparent visual magnitude of 4.46. Based upon an annual parallax shift of 18.46 mas, it is located around 177 light years away from the Sun. At that distance, the visual magnitude is reduced by an interstellar extinction factor of 0.1.

This is an evolved, G-type giant star with a stellar classification of G8 III. It is a red clump giant, which means it has undergone helium flash and is currently generating energy through the fusion of helium at its core. Beta Fornacis has 1.33 times the mass of the Sun and, at an age of 3.3 billion years, has expanded to 10.5 times the Sun's radius. It is radiating 51 times the solar luminosity from its outer atmosphere at an effective temperature of 4,790 K.

Nu Fornacis, Latinized from ν Fornacis, is a single, variable star in the southern constellation of Fornax. It is blue-white in hue and faintly visible to the naked eye with an apparent visual magnitude that fluctuates around 4.69. This body is located approximately 370 light years distant from the Sun based on parallax, and is drifting further away with a radial velocity of +18.5 km/s. It is a candidate member of the Pisces-Eridanus stellar stream, which suggests an age of 120 million years or less.

This object is an Ap star with a stellar classification of B9.5IIIspSi matching a late B-type giant star. The 'Si' suffix indicates an abundance anomaly of silicon. It is an Alpha Canum Venaticorum variable that ranges from magnitude 4.68 down to 4.73 with a period of 1.89 days – the same as its rotational period. It is 3.65 times as massive and 245 times as luminous as the Sun, with 3.44 times the Sun's diameter.

Procyon (/ˈproʊsi.ɒn/) is the brightest star in the constellation of Canis Minor and usually the eighth-brightest star in the night sky, with an apparent visual magnitude of 0.34. It has the Bayer designation α Canis Minoris, which is Latinized to Alpha Canis Minoris, and abbreviated α CMi or Alpha CMi, respectively. As determined by the European Space Agency Hipparcos astrometry satellite, this system lies at a distance of just 11.46 light-years (3.51 parsecs), and is therefore one of Earth's nearest stellar neighbors.

A binary star system, Procyon consists of a white-hued main-sequence star of spectral type F5 IV–V, designated component A, in orbit with a faint white dwarf companion of spectral type DQZ, named Procyon B. The pair orbit each other with a period of 40.84 years and an eccentricity of 0.4.

Alpha Doradus, Latinized from α Doradus, is the brightest star in the southern constellation of Dorado. The distance to this system, as measured using the parallax method, is about 169 light-years (52 parsecs).

This is a binary star system with an overall apparent visual magnitude that varies between 3.26 and 3.30, making this one of the brightest naked-eye binary stars. The system consists of a subgiant star of spectral type B revolving around a giant star with spectral type A in an eccentric orbit with a period of about 12 years. The orbital separation varies from 2 astronomical units at periastron to 17.5 astronomical units at apastron. The primary, α Doradus A, is a chemically peculiar star whose atmosphere displays an abnormally high abundance of silicon, making this an Si star.

Delta Crateris (δ Crt, δ Crateris) is a solitary star in the southern constellation of Crater. With an apparent visual magnitude of 3.56, it is the brightest star in this rather dim constellation. It has an annual parallax shift of 17.017 mas as measured from Earth, indicating Delta Crateris lies at a distance of 192 ly from the Sun.

Beta Crateris, Latinized from β Crateris, is a binary star system in the southern constellation of Crater. It is visible to the naked eye with an apparent visual magnitude of 4.46. Based upon an annual parallax shift of 9.59 mas as seen from Earth, it is around 340 light years from the Sun.

This is an astrometric binary star system with an orbital period of 6.0 years and a projected separation of 8.3 AU. The orbit has an estimated semimajor axis of 9.3 AU. The primary component A is listed as an A-type giant star with a stellar classification of A2 III. However, Houk and Smith-Moore (1988) give a main sequence classification of A1 V, while Abt and Morrell (1995) list it as a subgiant star with a class of A2 IV. The spectrum shows enhanced barium, possibly as a result of a previous mass transfer event.

HD 209458 is a star with an orbiting exoplanet in the constellation Pegasus. It has an apparent visual magnitude of 7.65 and an absolute magnitude of 4.28. Because it is located at a distance of 157 light-years (48 parsecs) from the Sun as measured via parallax, it is not visible to the unaided eye. With good binoculars or a small telescope it should be easily detectable. The system is drifting closer with a heliocentric radial velocity of −14.8 km/s.

Gamma Pegasi is a binary star in the constellation of Pegasus, located at the southeast corner of the asterism known as the Great Square. It has the formal name Algenib /ælˈdʒiːnɪb/; the Bayer designation Gamma Pegasi is Latinized from γ Pegasi and abbreviated Gamma Peg or γ Peg. The average apparent visual magnitude of +2.84 makes this the fourth-brightest star in the constellation. The distance to this system has been measured using the parallax technique, yielding a value of roughly 470 light-years (144 parsecs).

Alpheratz is a prominent star system in the constellation of Andromeda. Pronounced /ælˈfɪəræts/, it has the Bayer designation Alpha Andromedae, Latinised from α Andromedae, and abbreviated Alpha And or α And, respectively. Alpheratz is the brightest star in the constellation when Mirach (β Andromedae) undergoes its periodical dimming. Immediately northeast of the constellation of Pegasus, it is the upper left star of the Great Square of Pegasus. It is located at a distance of 97 light-years from Earth.

Although it appears to the naked eye as a single star with overall apparent visual magnitude +2.06, it is actually a binary system composed of two stars in close orbit. The chemical composition of the brighter of the two stars is unusual as it is a mercury-manganese star whose atmosphere contains abnormally high abundances of mercury, manganese, and other elements, including gallium and xenon. It is the brightest mercury-manganese star known.

Aldebaran (Arabic: الدَّبَران, lit. 'The Follower') is a star in the zodiac constellation of Taurus. It has the Bayer designation α Tauri, which is Latinized to Alpha Tauri and abbreviated Alpha Tau or α Tau. Aldebaran varies in brightness from an apparent visual magnitude of 0.75 down to 0.95, making it the brightest star in the constellation, as well as (typically) the fourteenth-brightest star in the night sky. It is at a distance of approximately 67 light-years. The star lies along the line of sight to the nearby Hyades cluster, but is unrelated and much older than the young cluster.

Aldebaran is a red giant, meaning that it is cooler than the Sun with a surface temperature of 3,900 K, but its radius is about 45 times the Sun's, so it is over 400 times as luminous. As a giant star, it has moved off the main sequence on the Hertzsprung–Russell diagram after depleting its supply of hydrogen in the core. The star spins slowly and takes 520 days to complete a rotation.

The Ring Nebula is a planetary nebula in the northern constellation of Lyra, positioned about mid-way between the prominent stars Beta and Gamma Lyrae. It is catalogued as Messier 57, M57 and NGC 6720; Ring Nebula is its proper name. This nebula was discovered Charles Messier in 1779. It has an apparent visual magnitude of 8.8, which is too faint to be visible with the naked eye, but it can be readily observed with a small telescope.

A planetary nebula is formed when a star, during the last stages of its evolution before becoming a white dwarf, expels a vast luminous envelope of ionized gas into the surrounding interstellar space. The progenitor star for the ring nebula is now a carbon-oxygen white dwarf with an apparent visual magnitude of +15.75. Based on parallax measurements, this star is located at a distance of approximately 2,570 light-years (790 pc) from the Sun. After expanding for 1,610 years, the nebula currently has a diameter of 4.6 ly.

Barnard's Star is a small red dwarf star in the constellation of Ophiuchus. At a distance of 5.96 light-years (1.83 pc) from Earth, it is the fourth-nearest-known individual star to the Sun after the three components of the Alpha Centauri system, and is the closest star in the northern celestial hemisphere. Its stellar mass is about 16% of the Sun's, and it has 19% of the Sun's diameter. Despite its proximity, the star has a dim apparent visual magnitude of +9.5 and is invisible to the unaided eye; it is much brighter in the infrared than in visible light.

Barnard's Star is among the most studied red dwarfs because of its proximity and favorable location for observation near the celestial equator. Historically, research on Barnard's Star has focused on measuring its stellar characteristics, its astrometry, and also refining the limits of possible extrasolar planets. Although Barnard's Star is ancient, it still experiences stellar flare events, one being observed in 1998.

Crux (/krʌks/ KRUKS) is a constellation of the southern sky that is centred on four bright stars in a cross-shaped asterism commonly known as the Southern Cross. It lies on the southern end of the Milky Way's visible band. The name Crux is Latin for cross. Though it is the smallest of all 88 modern constellations, Crux is among the most easily distinguished, as each of its four main stars has an apparent visual magnitude brighter than +2.8. It has attained a high level of cultural significance in many Southern Hemisphere states and nations.

Blue-white α Crucis (Acrux) is the most southerly member of the constellation, and at magnitude 0.8, the brightest. The three other stars of the cross appear clockwise and in order of lessening magnitude: β Crucis (Mimosa), γ Crucis (Gacrux), and δ Crucis (Imai). ε Crucis (Ginan) also lies within the cross asterism. Many of these brighter stars are members of the Scorpius–Centaurus association, a large but loose group of hot, blue-white stars that appear to share common origins and motion across the southern Milky Way.

Mirach is a prominent star in the northern constellation of Andromeda. It is pronounced /ˈmaɪræk/ and has the Bayer designation Beta Andromedae, which is Latinized from β Andromedae. This star is positioned northeast of the Great Square of Pegasus and is potentially visible to all observers north of latitude 54° S. It is commonly used by stargazers to find the Andromeda Galaxy. The galaxy NGC 404, also known as Mirach's Ghost, is seven arcminutes away from Mirach.

This star has an apparent visual magnitude of around 2.07, varying between 2.01 and 2.10, which at times makes it the brightest star in the constellation. Based upon parallax measurements, it is roughly 197 light-years (60 parsecs) from the Solar System. Its apparent magnitude is reduced by 0.06 by extinction due to gas and dust along the line of sight. The star has a negligible radial velocity of 0.1 km/s, but with a relatively large proper motion, traversing the celestial sphere at an angular rate of 0.208″·yr.

NGC 7662 is a planetary nebula located in the northern constellation Andromeda. It is known as the Blue Snowball Nebula, Snowball Nebula, and Caldwell 22. This nebula was discovered October 6, 1784 by the German-born English astronomer William Herschel. In the New General Catalogue it is described as a "magnificent planetary or annular nebula, very bright, pretty small in angular size, round, blue, variable nucleus". The object has an apparent visual magnitude of 8.3 and spans an angular size of 32″ × 28″. Parallax measurements give a distance estimate of 5,730 ± 340 ly (1,757 ± 103 pc).

NGC 7662 is a popular planetary nebula for casual observers. A small telescope will reveal a star-like object with slight nebulosity. A 6" telescope with a magnification around 100x will reveal a slightly bluish disk, while telescopes with a primary mirror at least 16" in diameter may reveal slight color and brightness variations in the interior.

Altair is the brightest star in the equatorial constellation of Aquila and the twelfth-brightest star in the night sky. It has the Bayer designation Alpha Aquilae, which is Latinised from α Aquilae and abbreviated Alpha Aql or α Aql. Altair is an A-type main-sequence star with an apparent visual magnitude of 0.77 and is one of the vertices of the Summer Triangle asterism; the other two vertices are marked by Deneb and Vega. It is located at a distance of 16.7 light-years (5.1 parsecs) from the Sun. Altair is currently in the G-cloud—a nearby interstellar cloud formed from an accumulation of gas and dust.

Altair rotates rapidly, with a velocity at the equator of approximately 286 km/s. This is a significant fraction of the star's estimated breakup speed of 400 km/s. A study with the Palomar Testbed Interferometer revealed that Altair is not spherical, but is flattened at the poles due to its high rate of rotation. Other interferometric studies with multiple telescopes, operating in the infrared, have imaged and confirmed this phenomenon.

Alpha Persei (Latinized from α Persei, abbreviated Alpha Per, α Per), formally named Mirfak (pronounced /ˈmɜːrfæk/ or /ˈmɪərfæk/), is the brightest star in the northern constellation of Perseus, outshining the constellation's best-known star, Algol (β Persei). Alpha Persei has an apparent visual magnitude of 1.8, and is a circumpolar star when viewed from mid-northern latitudes.

Alpha Persei lies in the midst of a cluster of stars named as the eponymous Alpha Persei Cluster, or Melotte 20, which is easily visible in binoculars and includes many of the fainter stars in the constellation. Determined distance using the trigonometric parallax, places the star 510 light-years (160 parsecs) away.