Stars & Scopes Glossary
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Constellations Folklore Names for Full Moons Planets Moons of the Solar System
Aberration In an optical system, any departure from a spherically converging final wave front.
Absolute Magnitude The apparent magnitude of a star at 32.6 light-years (10 parsecs) away.
Achromatic A refracting optical system without color correction.
Adrastea A moon of Jupiter was discovered by David C. Jewitt and G. Edward Danielson on July 8, 1979. Adrastea is also designated as "Jupiter XV" and "S/1979 J1". In Greek mythology, Adrastea was a nymph, the daughter of Jupiter and Ananke.
Afocal Photography A type of eyepiece projection photography in which the camera lens is placed very close to a telescope's eyepiece
Airy Disk The central, brightest part of a normal Airy pattern.
Airy Pattern The diffraction pattern of a telescope with central Airy Disk and surrounding diffraction rings. An ideal telescope objective produces a diffraction-limited Airy pattern from an infinitely small, luminous object point.
Aitne A moon of Jupiter was discovered by Scott S. Sheppard and team in 2001. Aitne is also designated as "Jupiter XXXI" and "S/2001 J11". In Greek mythology, Aitne was a nymph who was seduced by Zeus.
Albiorix A moon of Saturn was discovered by Matthew Holm in 2000. Albiorix also is designated as "Saturn XXVI" and "S/2000 S11". In Celtic mytholoy, Albiorix, also known as Toutatis, is the god of tribal unity.
Alt-Azimuth Mount A type of telescope mount designed to move up and down (altitude) and left and right (azimuth).
Amalthea A moon of Jupiter was discovered by Edward Emerson Barnard on September 9, 1892. Amalthea was the first new moon of Jupiter to be discovered since Galileo Galilei discovered the Galilean moons in 1610. Amalthea is also designated as "Jupiter V". In Greek mythology, Amalthea was a nymph who nursed the infant Zeus (Jupiter) with goat's milk.
Ananke A moon of Jupiter was discovered by Seth Nicholson at Mount Wilson Observatory on September 28, 1951. Ananke is also designated as "Jupiter XII". In Greek mythology, Ananke was the personification of destiny, unalterable necessity and fate.
Andromeda The constellation "The Chained Maiden"
Angular Resolution The angular size of the smallest detail of an astronomical object that can be distinguished with a telescope.
Anti-Light Pollution (ALP) Filter A type of nebular filter that eliminates light frequencies from mercury and sodium vapor street lights.
Anti-Reflection Coatings Interference coatings on a lens surface to increase light transmission.
Antlia The constellation "The Air Pump"
Aoede A moon of Jupiter was discovered by Scott S. Sheppard and team in 2003. Aoede is also designated as "Jupiter XLI" and "S/2003 J7". In Greek mythology, Aoede was the Muse of song, and was a daughter of Zeus (Jupiter).
Aperture The measurement of the diameter of the main lens of an optical system.
Aphelion
Aphelion
Aphelion of Earth
The Aphelion occurs when a planet is furthest to the Sun during its slightly elliptical orbit.
Aplanatic To be free of coma and spherical aberration.
Apochromatic An optical system without color aberration and free of secondary spectrum.
Apparent Magnitude The relative brightness of a star as view from Earth.
Apus The constellation "The Bird of Paradise"
Aquarius Aquarius (The Water Bearer) is a zodiacal constellation, that is, it lies across the ecliptic, an imaginary line across the sky that the Sun, Moon and all the planets except Pluto seem to move along. There are 3 deep sky objects that are on the Messier catalog, the Globular Cluster M2, Globular Cluster M72, and the Open Cluster M73. Also in Aquarius, is the Saturn Nebula NGC-7009 and the Helix Nebula NGC-7293.
Aquila The constellation "The Eagle"
Ara The constellation "The Altar"
Arche A moon of Jupiter was discovered by Scott S. Sheppard and team in 2002. Arche is also designated as "Jupiter XLIII" and "S/2002 J1". In Greek mythology, Arche was one of the four original Muses, an addition to the earlier three (Aoede, Melete, and Mneme).
Arcminute One-sixtieth of a degree of arc.
Arcsecond One-sixtieth of a minute of arc. 1/3600 of a degree.
Ariel A moon of Uranus was discovered by William Lassell on October 24, 1851. Ariel is also designated as "Uranus I". Ariel was the spirit who serves Prospero in Shakespeare's The Tempest.
Aries Aries (The Ram) is a zodiacal constellation, that is, it lies across the ecliptic, an imaginary line across the sky that the Sun, Moon and all the planets except Pluto seem to move along. Aries has a few dim deep sky objects including the galaxies NGC-697, NGC-772, NGC-972 and NGC-1156.
Asterism A recognizable grouping of stars which is a subset of a Constellation. For Example: 'The Big Dipper' is an asterism of the Constellation Ursa Major (The Big Bear) or 'Pleiades' is an asterism in the Constellation Taurus (The Bull).
Asteroid Large piece of rock orbiting the sun, usually located in the asteroid belt between Mars and Jupiter.
Astigmatism An optical aberration that causes the image of a point light source to appear as an ellipse.
Astronomical Season Rule This is a rule to define a Blue Moon based on the "Maine Rule," but using the actual Equinoxes and Solstices instead of the circular orbit of a fictitious mean Earth to define the seasons.
Astronomical Unit A measurement of distance equal to the distance from the Sun to the circular orbit of a Fictious Mean Earth or about 92,955,807 miles.
Atlas A moon of Saturn was discovered by Richard Tirrile (Voyager 1) in 1980. Atlas also is designated as "Saturn XV" and "S/1980 S28". In Greek mythology, Atlas was a titan who held the sky up.
AU Abbreviation for an "Astronomical Unit" which is a measurement of distance equal to the distance from the Sun to the circular orbit of a Fictitious Mean Earth or about 92,955,807 miles.
Auriga The constellation "The Charioteer"
Aurora Light emission in the sky around the north and south poles caused by charged particles from the solar wind hitting the Earth magnetic field.
Autonoe A moon of Jupiter was discovered by Scott S. Sheppard and team in 2001. Autonoe is also designated as "Jupiter XXVIII" and "S/2001 J1". In Greek mythology, Autonoe was a daughter of Cadmus, founder of Thebes, and the goddess Harmonia.
Autumnal Having to do with the season of Autumn. The Autumnal Equinox is the beginning of Fall.
Averted Vision An observing technique in which a faint object image may be made to appear brighter to the eye by not looking directly at it.
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Constellations Folklore Names for Full Moons Planets Moons of the Solar System
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The "Stars and Scopes" Glossary was compiled by Peter Ue from various sources on the internet. I tried to correct and edit as much as possible, but I can make no claim or warrenty to the information here. If you find any errors just contact me and I'll try to fix it - Thanks , Peter.

 

 

 

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