Astronomy: General
- aberration of starlight
- absolute magnitude
- Adrastea
- aerolite
- albedo
- Alfonsine tables
- Almagest
- Alphonsine tables
- altazimuth coordinate system
- altazimuth mounting
- Amalthea
- American Ephemeris and Nautical Almanac
- Ananke
- Andromeda Galaxy
- anomalistic year
- apastron
- aphelion
- apogee
- apparent magnitude
- apparent solar time
- apsides
- apsis
- Aquarids
- Arrokoth
- asteroid
- astrolabe
- astrometry
- astronomical coordinate systems
- Astronomical Ephemeris
- astronomical unit
- astronomy
- astrophysics
- Atlas
- azimuth
- Baily's beads
- Beehive
- Belinda
- Bianca
- big-bang theory
- binary star
- black hole
- blink microscope
- blue shift
- Bode's law
- bolide
- Brahic, André Fernand
- Braille
- brown dwarf
- Caliban
- Callirrhoë
- Callisto
- Calypso
- carbon-nitrogen-oxygen cycle
- Carme
- Cassegrain focus
- Cassini's division
- celestial equator
- celestial horizon
- celestial mechanics
- celestial meridian
- celestial pole
- celestial sphere
- Cepheid variables
- Ceres
- Chaldene
- Charon
- chondrite
- chromosphere
- circumpolar star
- civil time
- cluster
- Coalsack
- COBE
- color index
- coma
- comet
- conjunction
- Copernican system
- Cordelia
- corona
- coronagraph
- Cosmic Background Explorer
- Coudé focus
- counterglow
- Crab Nebula
- Cressida
- culminate
- cycle
- dark energy
- dark matter
- day
- daylight saving time
- declination
- Deimos
- Desdemona
- Despina
- Dione
- diurnal circle
- dog days
- double star
- Draconids
- dwarf planet
- dwarf star
- Dysnomia
- eccentricity
- eclipse
- eclipsing binary star
- ecliptic
- ecliptic coordinate system
- Elara
- elongation
- emerald flash
- Enceladus
- encounter theory
- ephemeris
- ephemeris time
- epicycle
- Epimetheus
- equation of time
- equatorial coordinate system
- equatorial mounting
- equinox
- Erinome
- Eris
- Eros
- escape velocity
- Europa
- evening star
- exoplanet
- expanding universe
- faculae
- failed star
- falling star
- filament
- fireball
- flare, solar
- flash spectrum
- flocculi
- Foucault pendulum
- Fraunhofer lines
- galactic cluster
- galactic coordinate system
- Galatea
- galaxy
- gamma-ray astronomy
- Ganymede
- gegenschein
- Geminids
- geocentric system
- giant star
- gibbous phase
- globular cluster
- gnomon
- granule
- gravitational collapse
- green flash
- Greenwich mean time
- Hale Observatories
- Halley's comet
- Harpalyke
- harvest moon
- Helene
- heliocentric system
- Hercules cluster
- Hermes
- Hertzsprung-Russell diagram
- Hidalgo
- Himalia
- horizon
- horizon coordinate system
- Horsehead Nebula
- hour angle
- hour circle
- Hubble's law
- hunter's moon
- Hyades
- Hyperion
- Iapetus
- Icarus
- inclination
- inferior planet
- Infrared Astronomical Satellite
- infrared astronomy
- Infrared Space Observatory
- interstellar matter
- Io
- Iocaste
- IRAS
- Isonoe
- Janus
- Jovian planets
- Julian Day calendar
- Juliet
- Juno
- Jupiter
- Kalyke
- Kepler's laws
- Kirkwood gaps
- Kuiper Airborne Observatory
- Kuiper belt
- Lagoon Nebula
- Large Magellanic Cloud
- Larissa
- Leda
- light-year
- limb darkening
- Local Group
- local solar time
- luminosity
- Lyrids
- Lysithea
- Magellanic Clouds
- magnitude
- main-sequence star
- Major Planets of the Solar System
- Maksutov telescope
- maria
- Mars
- mascon
- mass-luminosity relation
- mean solar time
- Megaclite
- Mercury
- meridian circle
- Messier catalog
- meteor
- meteor shower
- meteorite
- meteoroid
- Metis
- Metonic cycle
- midnight sun
- Milky Way
- Mimas
- minor planet
- Miranda
- moon
- morning star
- nadir
- Naiad
- Nautical Almanac
- nebula
- nebular hypothesis
- Neptune
- Nereid
- neutrino astronomy
- neutron star
- New General Catalog
- Newtonian focus
- NICMOS
- node
- North American Nebula
- nova
- nucleosynthesis
- nutation
- Oberon
- obliquity of the ecliptic
- observatory
- occultation
- Oort cloud
- open cluster
- Ophelia
- opposition
- optical double
- orbit
- Orion Nebula
- Pallas
- Pan
- Pandora
- parallax
- parsec
- Pasiphaë
- penumbra
- periastron
- perigee
- perihelion
- Perseids
- perturbation
- phase
- Phobos
- Phoebe
- photographic magnitude
- photosphere
- plage
- planet
- planetarium
- planetary nebula
- planetary science
- planetary system
- planetesimal theory
- planetoid
- Pleiades
- Pluto
- population I and II
- Portia
- Praesepe
- Praxidike
- precession of the equinoxes
- Prometheus
- prominences
- proper motion
- Proteus
- proton-proton cycle
- protoplanet theory
- Ptolemaic system
- Puck
- pulsar
- quadrature
- quasar
- quasi-stellar object
- radar astronomy
- radial velocity
- radiant
- radio astronomy
- radio telescope
- red giant
- red shift
- reflector
- refractor
- resolving power
- retrograde motion
- Rhea
- right ascension
- rille
- ring
- Ring nebula
- Roche limit
- Rosalind
- RR Lyrae
- saros
- satellite, artificial
- satellite, natural
- Saturn
- Schmidt telescope
- Sedna
- seeing
- sextant
- shooting star
- sidereal day
- sidereal period
- sidereal time
- sidereal year
- siderolite
- Signs of the Zodiac
- Sinope
- Small Magellanic Cloud
- SOFIA
- solar constant
- solar system
- solar time
- solar wind
- solstice
- Space Infrared Telescope Facility
- spectral class
- Spectral Classes for Main Sequence Stars
- spectroheliograph
- spectroscopic binary
- spicule
- spiral nebula
- Spitzer Space Telescope
- standard time
- star
- star cluster
- Star of Bethlehem
- steady-state theory
- stellar evolution
- stellar populations
- stellar structure
- Stratospheric Observatory for Infrared Astronomy
- sun
- sunspots
- supergiant star
- superior planet
- supernova
- Sycorax
- synchrotron radiation
- synodic period
- syzygy
- Taygete
- telescope
- Telesto
- terrestrial planet
- Tethys
- Thalassa
- Thebe
- Themisto
- tidal theory
- time zone
- Titan
- Titania
- Titius-Bode law
- transit
- transit instrument
- Triton
- Trojan asteroids
- tropical year
- twilight
- twinkling
- Ultima Thule
- ultraviolet astronomy
- umbra
- Umbriel
- universal time
- universe
- Uranus
- variable star
- Venus
- vernal equinox
- vertical circle
- Vesta
- virtual observatory
- virtual telescope
- visual binary
- visual magnitude
- Vulcan
- white dwarf
- Widmanstätten figures
- Wolf-Rayet star
- X-ray astronomy
- Xena
- year
- zenith
- zodiac
- zodiacal band
- zodiacal light
- ‘Oumuamua
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