This page lists the 5027 tags that currently have astronomical definitions.
This page lists the 5027 tags that currently have astronomical definitions.
21-cm line, 21 cm line
21 centimeter line of hydrogen
53 Persei star
Abell cluster
optical aberration, aberration
aberration of optical image
aberration
aberration of light
ablation
abnormal spectrum
absolute magnitude
absolute temperature scale
absorption
absorption coefficient, absorptivity
absorption line
absorption line system
dark nebula, absorption nebula
absorption spectroscopy
absorption spectrum
absorption coefficient, absorptivity
abundance, chemical abundance, element abundance, stellar abundance
abundance ratio
Bailey type, AB variable star
actinium, Ac
actinium (atomic number 89)
acceleration
surface gravity, acceleration of gravity
gravity, acceleration of gravity
Acceleration of particles
accretion
Accretion, accretion disks
accretion disk
accretion discs UK
achondrite
acoustics
acoustic wave, sound, sound wave
actinium, Ac
actinium (atomic number 89)
active galactic nucleus, AGN
active galaxy, eruptive galaxy
active optics
active prominence
active region
solar active region
active star
active Sun
activity index
adaption
adaptive optics
adiabatic process
adjustment
adsorption
A dwarf
A dwarf star
antenna, aerials, antennas
aerolite
aeronomy
Ae star
afterglow
silver, Ag
silver (atomic number 47)
age
A giant
A giant star
active galactic nucleus, AGN
air
air conditioning
airglow, dayglow, nightglow
airplane-borne instrument, airplane borne instrument
air pollution
cosmic ray shower, air shower, auger shower
Airy disk
Airy discs UK
delta Scuti star, AI Velorum star
aluminum, Al
aluminum (atomic number 13)
albedo, spherical albedo
Alfven surface
Alfven wave, hydromagnetic wave
Algol variable star, beta Persei star
alignment optics
alignment of optical image
all-sky camera, all sky camera
all-sky photography, all sky photography
almanac
alpha2 Canum Venaticorum star
alpha particle
altazimuth mounting, alt-azimuth mounting, azimuth mounting
altimeter
altimetry
altitude angle, elevation angle
altitude [angle]
aluminizing
aluminum, Al
aluminum (atomic number 13)
aluminum coating
aluminium coating UK
americium, Am
americium (atomic number 95)
amateur astronomy
AM Canum Venaticorum star
americium, Am
americium (atomic number 95)
AM Herculis star, polars
ammonia
Amor group
amplifier
amplitude
Am star
analog recorder
analysis
archaeoastronomy, ancient astronomy, astroarchaeology
anemometer
refraction angle, angle of refraction
angle of refraction
spherical coordinate, angular coordinate
angular diameter, apparent diameter
angular separation, angular distance
angular momentum
angular resolution
angular separation, angular distance
angular velocity
anisotropy
annual equation
annual parallax, heliocentric parallax, parallax
annular eclipse
anomalistic month
anomalistic year
anomaly
ansa
antapex
antarctic observatory
antenna, aerials, antennas
antenna design
antenna, aerials, antennas
anthropic principle
Galactic anticenter, anticenter
antimatter
antimony, Sb
antimony (atomic number 51)
antineutrino
antinode
antinucleon
antiparticle
antiproton
antireflection coating
apastron
aperiodic comet
aperture
aperture synthesis, synthetic aperture
apex
aphelion
apocenter
apodization, apodisation UK
apodization, apodisation UK
apogee
Apollo group
orbital anomaly, apparent anomaly
orbital_anomaly
angular diameter, apparent diameter
apparent intensity
apparent magnitude
apparent position, apparent places
apparent position, apparent places
apparent superluminal motion, superluminal motion
apsis, apse
apsidal motion
apsis, apse
Ap star, peculiar A star
argon, Ar
argon (atomic number 18)
arc
archaeoastronomy, ancient astronomy, astroarchaeology
surface photometry, area photometry
argon, Ar
argon (atomic number 18)
spiral arm, arm
armillary sphere
array
array processor
arsenic, As
arsenic (atomic number 33)
artificial satellite
arsenic, As
arsenic (atomic number 33)
ascending node
ashen light
A star
astatine, At
astatine (atomic number 85)
asteroid, minor planet, planetoid
asteroid belt
asteroid occultation
occultation by asteroid
asteroseismology, stellar seismology
astigmatism
archaeoastronomy, ancient astronomy, astroarchaeology
astrodynamics
astrograph
astrographic camera
astrographic catalog, astrographic catalogues UK
astrographic catalog, astrographic catalogues UK
astrolabe
astrology
astrometric binary star
astrometric instrument
Astrometry and celestial mechanics
astronomer
astronomical constant
Astronomical data bases
Astronomical data bases: miscellaneous
astronomical geodesy
instrument, astronomical instrument, instrumentation
Astronomical instrumentation, methods and techniques
astronomical optics
astronomical research
astronomical technique
Astronomical Unit, A.U., AU
astronomy
photography, astrophotography
jet, astrophysical jet
astrophysics
A subdwarf
A subdwarf star
A subgiant
A subgiant star
A supergiant
A supergiant star
asymptotic giant branch, AGB
astatine, At
astatine (atomic number 85)
ataxite
atlas, chart
Atlases
atmosphere
atmospheric density
Atmospheric effects
atmospheric extinction, extinction
atmospheric radiation, sky radiation
atmospheric refraction
atmospheric scattering
atmospheric scintillation, twinkling
atmospheric tide
atmospheric window
atom
atomic clock, caesium clock, cesium clock
Atomic data
atomic line
atomic physics
atomic process
Atomic processes
atomic spectrum
atomic time
attenuation
cosmic ray shower, air shower, auger shower
aurora
auroral arc
auroral jet
australite
auto-correlation, autocorrelation
autoguider
automated telescope, robotic telescope
automatic patrol telescope
autumnal equinox
auxiliary instrument
avalanche photodiode
axial ratio
axion
axis
azimuth, bearing
altazimuth mounting, alt-azimuth mounting, azimuth mounting
boron, B
boron (atomic number 5)
barium, Ba
barium (atomic number 56)
Baade-Wesselink method
background
background noise
background radiation, radiation background
barium star, Ba II star
Bailey type, AB variable star
bailys bead
Baily's bead
Baker-Nunn camera
balloon-borne instrument, balloon borne instrument
Balloons
Balmer continuum
Balmer limit
Balmer series, Balmer line
Balmer series, Balmer line
barium, Ba
barium (atomic number 56)
barium star, Ba II star
barometer
barred spiral galaxy
baryon
baryonic Dark Matter
basin
B band
B dwarf
B dwarf star
beryllium, Be
beryllium (atomic number 4)
beam switching
beam waveguide
beamwidth
azimuth, bearing
double-mode Cepheid, beat_Cepheid, double mode Cepheid
bediasite
Be star, Be dwarf star
berkelium, Bk
berkelium (atomic number 97)
beryllium, Be
beryllium (atomic number 4)
Besselian epoch
Bessel photometry, Bessel UBVRI photometry
Bessel photometry, Bessel UBVRI photometry
Be star, Be dwarf star
beta Cephei star, beta Canis Majoris star
beta Cephei star, beta Canis Majoris star
beta Lyrae star
Algol variable star, beta Persei star
B galaxy
barred galaxy (Yerkes classification scheme)
B giant
B giant star
bohrium, Bh
bohrium (atomic number 107)
bismuth, Bi
bismuth (atomic number 83)
Bianchi cosmology
bias calibration
Big Bang theory
binary star, binaries, double star
Binaries: close
Binaries: eclipsing
Binaries: general
Binaries: spectroscopic
Binaries: symbiotic
Binaries: visual
double galaxy, binary galaxy
binary pulsar
binary star, binaries, double star
binary system
biology
bipolar outflow, bipolar flow
bipolar galaxy
bipolar group
bipolar nebula
bipolar outflow, bipolar flow
birth rate
bismuth, Bi
bismuth (atomic number 83)
berkelium, Bk
berkelium (atomic number 97)
black body radiation, thermal black body radiation
black dwarf
black dwarf star
black hole
Black hole physics
blank field
blazar
Blazhko effect
BL Herculis star
blink comparator
blinking
BL Lacertae object, BL Lac object
BL Lacertae objects: general
BL Lacertae object, BL Lac object
blue galaxy
blue loop
blue object
blueshift, blue shift, blue-shift
early-type star, blue star, early type star, hot star
Blue stragglers
blue straggler star
B magnitude
Bodes law, Titius-Bode law
Bode's law
bohrium, Bh
bohrium (atomic number 107)
Bok globule
bolide
bolometer
bolometric correction
boron, B
boron (atomic number 5)
Bose-Einstein nucleus
Bose-Einstein statistics
boson
boundary layer
bound-free transition, bound free transition
Bouwers telescope
bow shock
bow-shock
Bp star
bromine, Br
bromine (atomic number 35)
Brackett series
bremsstrahlung, free free transition, free-free transition
bridge
bright galaxy
bright nebula
brightness
brightness distribution
brightness temperature
bright point
solar bright point
bright star
brillouin scattering
brillouin spectrum
broad band photometry, wide-band photometry
broad-band photometry
bromine, Br
bromine (atomic number 35)
brown dwarf
B star
B subdwarf
B subdwarf star
B supergiant
B supergiant star
bubble
bulge
Cepheid, Cepheid variable star, bump Cepheid, classical Cepheid, delta Cephei star
Burkert profile
Burkert mass-profile
burst
burster
butterfly diagram
BV photometry
Bw star
BY Draconis star
carbon, C
carbon (atomic number 6)
calcium, Ca
calcium (atomic number 20)
cadmium, Cd
cadmium (atomic number 48)
caesium, Cs, cesium
caesium (atomic number 55)
atomic clock, caesium clock, cesium clock
Ca II emission line
calcium, Ca
calcium (atomic number 20)
calcium line
calendar
calibration
californium, Cf
californium (atomic number 98)
camera
camera lens
luminescence, candoluminescence
canyon
Cape photometry, UCBV photometry
Cape RI photometry
capture
carbon, C
carbon (atomic number 6)
carbonaceous chondrite
carbon burning
carbon compound
carbon nitrogen cycle, CNO cycle, carbon cycle
carbon flash, carbon detonation
carbon dioxide, CO2, CO_2
carbon disulfide
carbon flash, carbon detonation
carbon line
carbon monosulfide, CS
carbon monoxide, CO
carbon nitrogen cycle, CNO cycle, carbon cycle
carbon star, C star
Cassegrain antenna, Cassegrain antennas, two reflector antennas, two-reflector antennas
Cassegrain antenna, Cassegrain antennas, two reflector antennas, two-reflector antennas
Cassegrain focus
Cassegrain telescope
cataclysmic variable star, CV, cataclysmic binary star, eruptive variable star
cataclysmic variable star, CV, cataclysmic binary star, eruptive variable star
catadioptric system
catalog, catalogues UK
Catalogs
catalog, catalogues UK
catastrophe theory
cathode
catoptric system
caustic
caustic crossing
charge-transfer device, CCD, charge transfer device
charge-coupled device, CCD, charge coupled device
CCD detector, CCD camera
CCD detector, CCD camera
CCD observation
CCD photometry
cadmium, Cd
cadmium (atomic number 48)
cD galaxy
cD galaxy (compact D galaxy in the Yerkes classification scheme)
cerium, Ce
cerium (atomic number 58)
equatorial coordinate system, celestial coordinate, equatorial system
celestial coordinate system
celestial equator
Declination, celestial latitude
Right Ascension, celestial longitude
celestial pole
celestial sphere
celsius temperature scale
center
center of mass
central star
centrifugal force
centripetal force
Cepheid, Cepheid variable star, bump Cepheid, classical Cepheid, delta Cephei star
Cepheid distance
Cepheids
Cepheid, Cepheid variable star, bump Cepheid, classical Cepheid, delta Cephei star
Cerenkov counter, Cherenkov counter
Cerenkov radiation, Cerenkov effect
Cerenkov radiation, Cerenkov effect
Ceres
cerium, Ce
cerium (atomic number 58)
caesium, Cs, cesium
caesium (atomic number 55)
atomic clock, caesium clock, cesium clock
californium, Cf
californium (atomic number 98)
hydrated carbon, CH
CH molecule
methane, CH4, CH_4
methane molecule
Chandler wobble, polar wandering
Chandrasekhar mass
Chandrasekhar limit
Chandrasekhar limit; the mass-limit for a degenerate stellar object
Chandrasekhar-Schoenberg limit, Chandrasekhar-Schonberg limit, Schoenberg-Chandrasekhar limit, Schonberg-Chandrasekhar limit
Chandrasekhar-Schoenberg limit; the mass-limit for an isothermal stellar core
Chandrasekhar-Schoenberg limit, Chandrasekhar-Schonberg limit, Schoenberg-Chandrasekhar limit, Schonberg-Chandrasekhar limit
Chandrasekhar-Schoenberg limit; the mass-limit for an isothermal stellar core
Chaos
charge-coupled device, CCD, charge coupled device
ion, charged particle
charge-injection device, CID, charge injection device
charge-transfer device, CCD, charge transfer device
atlas, chart
abundance, chemical abundance, element abundance, stellar abundance
chemical composition
chemical element
chemical evolution
chemiluminescence
chemistry
Cerenkov counter, Cherenkov counter
chlorine, Cl
chlorine (atomic number 17)
chondrite
chondrules
chromatic aberration
chromium, Cr
chromium (atomic number 24)
chromosphere
prominence, chromospheric eruption
flare, chromospheric eruption
chronometer, chronograph
chronometer, chronograph
CH star
charge-injection device, CID, charge injection device
C I emission
C II region
circular orbit
circular polarization, circular polarisation UK
circular polarization, circular polarisation UK
circumplanetary matter
circumstellar matter, circumstellar cloud, stellar envelope
circumstellar disk
circumstellar discs UK
circumstellar dust
circumstellar envelope, stellar envelope
circumstellar gas
circumstellar grain
circumstellar matter, circumstellar cloud, stellar envelope
Circumstellar matter
circumstellar shell, stellar envelope
civil time
chlorine, Cl
chlorine (atomic number 17)
Cepheid, Cepheid variable star, bump Cepheid, classical Cepheid, delta Cephei star
classical nova, nova
classical T Tauri star, CTTS
classification
clean method
clock
close binary star
closed universe
close encounter
cloud
cloud monitor
Magellanic cloud, Clouds of Magellan
clumping
cluster
clustering
galaxy cluster, cluster of galaxies, galaxy clustering
cluster of galaxies
star cluster, cluster of star
moving cluster parallax, cluster parallax
RR Lyrae star, cluster type variable star
curium, Cm
curium (atomic number 96)
Cosmic microwave background, CMB
color-magnitude relation, c m diagram, c m relation, c-m diagram, c-m relation, color magnitude relation, color-magnitude diagram
coronal mass ejection, CME
Sun: coronal mass ejections, CMEs
color-magnitude relation, c m diagram, c m relation, c-m diagram, c-m relation, color magnitude relation, color-magnitude diagram
cyanogen, CN
CNO anomaly
carbon nitrogen cycle, CNO cycle, carbon cycle
CN star
carbon dioxide, CO2, CO_2
coating
cobalt, Co
cobalt (atomic number 27)
magnetic star, cobalt star
cocoon star
coelostat
coherence
cold Dark Matter
collapse
collapsed star, collapsed object, collapsing star
collapsed star, collapsed object, collapsing star
collapsing cloud
collapsed star, collapsed object, collapsing star
collimation
collimator
collision
collisional excitation
collisional plasma
collision broadening
collision process
collision spectroscopy
collision strength
color
color equation
color excess
optical filter, color filter
colorimetry
color index
color-luminosity relation, color luminosity relation
color-magnitude relation, c m diagram, c m relation, c-m diagram, c-m relation, color magnitude relation, color-magnitude diagram
Hertzsprung-Russell and C-M diagrams, Color-Magnitude diagrams, H-R and C-M diagrams, H-R and CM diagrams, HR and C-M diagrams, HR and CM diagrams, Hertzsprung-Russel and Color-Magnitude diagrams, Hertzsprung-Russel diagrams
color-magnitude relation, c m diagram, c m relation, c-m diagram, c-m relation, color magnitude relation, color-magnitude diagram
color photography
color-redshift relation, color redshift relation
color vision
comatic aberration, coma
comatic aberration (coma)
comet
cometary globule
Comets: general
compact galaxy
compact H II region
compact nebula
compact nucleus
compact object
compact source
companion galaxy
companion star
comparison
comparison lamp
comparison star
component
composite particle
composition
Compton effect
Compton scattering
computer
computer application
computer model
computer program
computer simulation
computing
condensation
conjunction
constant
constellation
contact binary star
galaxy structure, content of galaxy, structure of galaxy
structure of galaxy
continent
continental drift
continuous spectrum
continuum radiation
contiuum
contour map
contraction
contrast
control system
convective envelope
convective shell
convective zone
late-type dwarf, cool dwarf star, late type dwarf star
late-type dwarf star
late-type giant, cool giant star, late type giant star
late-type giant star
cooling
cooling flow
Cooling flows
late-type star, cool star, late type star
late-type subdwarf, cool subdwarf star
late-type supergiant, cool supergiant star
late-type supergiant star
coordinated Universal Time, UTC
coordinate system
copper, Cu
copper (atomic number 29)
core
corona, coronas
coronagraph
coronal dimming
solar coronal dimming
coronal hole
coronal line
coronal loop
coronal mass ejection, CME
coronal plume
coronal transient
coronal wave
solar coronal wave
corona, coronas
corpuscular emission
field corrector, correcting lens
correction
corrector plate
correlation
cosmic
cosmic abundance
cosmic background radiation
cosmochemistry, astrochemistry, cosmic chemistry
dust, cosmic dust
cosmic electrodynamics
gamma-ray burst, GRB, cosmic gamma ray burst, cosmic gamma-ray burst, gamma ray burst
Cosmic microwave background, CMB
cosmic noise
plasma, cosmic plasma
cosmic ray, cosmic radiation, primary cosmic ray
cosmic ray, cosmic radiation, primary cosmic ray
cosmic ray astronomy
Cosmic rays
cosmic ray shower, air shower, auger shower
cosmic ray source
cosmic string, string
cosmic year
cosmochemistry, astrochemistry, cosmic chemistry
cosmochronology, nucleocosmochronology
cosmogony
cosmological constant, Lambda
cosmological distance scale
cosmological model
cosmological parameter
cosmological parameter/constant
Cosmological parameters
Cosmic microwave background, CMB
Cosmological parameters
Dark matter
Diffuse radiation
Distance scale
Early universe
Large-scale structure of Universe
Cosmology: miscellaneous
Cosmology: observations
Cosmology: theory
universe, cosmos
Coude focus
Coude spectrograph
Coude spectrum
counter, count
gegenschein, counterglow
counting, count
coupling
chromium, Cr
chromium (atomic number 24)
crater
cross-correlation, cross correlation
crust
crustal dynamics
cryogenics
cryostat
CS
CS molecule
carbon monosulfide, CS
caesium, Cs, cesium
caesium (atomic number 55)
giant, CS star
giant star
carbon star, C star
classical T Tauri star, CTTS
copper, Cu
copper (atomic number 29)
curium, Cm
curium (atomic number 96)
current
current sheet
field curvature, curvature of field
curve of growth
cusp
cusp crossing
cataclysmic variable star, CV, cataclysmic binary star, eruptive variable star
Novae, cataclysmic variables, CV
cyanoacetylene
cyanodiacetylene
cyanogen, CN
cyanogen line
cyanopolyene
cycle
cyclotron radiation
damping constant
Danjon astrolabe
dark adaption, retinal adaption
dark cloud
thermionic emission, dark current
dark-current calibration
Dark Energy, dark energy
dark nebula, absorption nebula
darkness
darkroom
darmtadtium, Ds
darmtadtium (atomic number 110)
DA star
DA white dwarf star
data acquisition
data analysis
database, data base
data center
data processing
data reduction
data retrieval
data storage
airglow, dayglow, nightglow
dubnium, Db
dubnium (atomic number 105)
DB star
DB white dwarf star
DDO photometry
dead-time calibration
space debris, debris
decay oscillation
decay of oscillation
deceleration
deceleration parameter, q-parameter
Declination, celestial latitude
deconvolution
defect
deformation
degenerate dwarf
degenerate dwarf star
degenerate matter
degenerate star
Cepheid, Cepheid variable star, bump Cepheid, classical Cepheid, delta Cephei star
delta delphini star
Delta Sct
delta Scuti star, AI Velorum star
dense cloud
Dense matter
densitometer
densitometry
density, specific gravity
density bounded
density distribution
density fluctuation
density perturbation
density variation
density wave model
descending node
design
de Sitter universe
destruction
detached binary star
detection
detector
detector array
determination
deuterium
deuterium, an isotope of hydrogen
D galaxy
rotationally symmetric elliptical galaxy (Yerkes classification scheme)
diagram
diameter
diamond ring effect
dichroic mirror
Dicke radiometer
differential equation
differential image motion monitor, DIMM
differential image-motion monitor
differential rotation
diffraction
diffraction grating, grating
diffraction patterns
diffuse nebula
digital image
digital recorder
dimension
differential image motion monitor, DIMM
differential image-motion monitor
diode
diode array
dioptric system
dipole
dipole antenna, dipole antennas
dipole antenna, dipole antennas
dirac cosmology
directional antenna, directional antennas
directional antenna, directional antennas
dirty snowball theory
discoloration
discoveries
discrete radio source
dish antenna, dish antennas
dish antenna, dish antennas
disintegration
disk
discs UK
disk flaring
disc flaring UK
disk galaxy
disc galaxy UK
disk population
disc population UK
disk star
disc star UK
dispersion
disruption
dissipation
distance
distance indicator
distance measurement
distance modulus, modulus
distortion
distribution function
distribution in space
diurnal parallax
diurnal phenomena
diurnal variation
D layer, D region
D line
dwarf nova, DN
dome, telescope dome
dome seeing
Doppler broadening
Doppler effect
DO star
DO white dwarf star
double galaxy, binary galaxy
double-mode Cepheid, beat_Cepheid, double mode Cepheid
double-mode pulsation, double mode pulsation
double-mode variable star, double mode variable star
double quasar
binary star, binaries, double star
DQ Herculis star
dredge up
D layer, D region
drift scan
drift wave
drive
darmtadtium, Ds
darmtadtium (atomic number 110)
dubnium, Db
dubnium (atomic number 105)
dust, cosmic dust
dust cloud
dust detector
Dust, extinction
dust grain
dust nebula
dust shell
dust storm
dwarf
dwarf star
dwarf Cepheid
dwarf galaxy
dwarf nova, DN
dwarf planet
dysprosium, Dy
dysprosium (atomic number 66)
dynamical evolution
dynamical friction
dynamical parallax
dynamical time
dynamics
dynamo theory
dysprosium, Dy
dysprosium (atomic number 66)
pre-main sequence star, early stage star, premainsequence star
early-type emission star, early type emission star
early-type galaxy, early type galaxy
early-type star, blue star, early type star, hot star
early-type supergiant, early type supergiant star
early-type supergiant star
early-type supergiant, early type supergiant star
early-type supergiant star
early-type variable star, early type variable star
Earth atmosphere, terrestrial atmosphere
Earth-Moon system, Earth Moon system
Earth orbit
earthquake
Earth rotation
Earth sciences
Earthshine
eccentric anomaly
eccentricity
elliptical orbit, eccentric orbit
echelle grating, echelons
echelle spectrograph, echelle spectrometer
echelle spectrograph, echelle spectrometer
echelle spectrum
echelle grating, echelons
eclipse
Eclipses
eclipsing binary star, eclipsing star, eclipsing variable star, photometric binary star
eclipsing binary star, eclipsing star, eclipsing variable star, photometric binary star
eclipsing binary star, eclipsing star, eclipsing variable star, photometric binary star
ecliptic
ecliptic coordinate system
ecliptic latitude
ecliptic longitude
ecliptic plane
ecliptic pole
E corona, E component, E-corona
E corona, E component, E-corona
Eddington limit
edge effect
Edgeworth-Kuiper belt, Kuiper belt
Edgeworth-Kuiper belt object, EKO, KBO, Kuiper belt object
teaching in astronomy, education
effective temperature
e-folding time
elliptical galaxy, e galaxy
E galaxy
elliptical galaxy (Yerkes classification scheme)
Einstein coefficient
Einstein effect, Einstein shift
einsteinium, Es
einsteinium (atomic number 99)
Einstein ring
Einstein effect, Einstein shift
Einstein universe
ejecta
ejection
Edgeworth-Kuiper belt object, EKO, KBO, Kuiper belt object
elasticity
E layer, E region
electrical property
electric charge
electric current
electric dipole
electric field
electricity
electrode
electrodynamics
electronographic camera, electrographic camera
electromagnetic
electromagnetic field
electromagnetic forces
electromagnetic interaction
electromagnetic radiation, electromagnetic wave
electromagnetic theory
electromagnetic radiation, electromagnetic wave
radiation scattering, electromagnetic wave scattering
electron
electron beam
electron density
electronic camera
electronic equipment
electronics
electronographic camera, electrographic camera
electron pumping
electron temperature
electrostatic wave
abundance, chemical abundance, element abundance, stellar abundance
elementary particle
Elementary particles
elementary particle scattering
element formation, formation of element
height, elevation
altitude [height]
altitude angle, elevation angle
altitude [angle]
ellipsoidal variable star, ellipsoidal binary star, photometric binary star
ellipsoidal variable star, ellipsoidal binary star, photometric binary star
elliptical galaxy, e galaxy
elliptical orbit, eccentric orbit
emerging flux
emission coefficient
emission line
emission line galaxy
emission line object
emission line star
emission nebula
emission process
emission spectrum
emissivity
encounter
energetic particle
energy
energy content
energy density
energy distribution
energy level
energy source
energy spectrum
energy-transfer, energy transfer
engineering
English mounting
enrichment
enthalpy
entropy
envelope
Ep galaxy
peculiar elliptical galaxy with dust absorption (modification of Yerkes classification scheme)
ephemeral active region
Ephemerides
ephemeris
ephemeris time
epoch
e-process
e process
equation of the center
equation of the equinox
equation of time
equator
equator correction
equator determination
equatorial bulge
equatorial coordinate system, celestial coordinate, equatorial system
equatorial mounting
equatorial coordinate system, celestial coordinate, equatorial system
equatorial zone
equator position
equilibrium
equilibrium figures
equinox
equinox correction
equinox position
equipotential surface
equivalent width
erbium, Er
erbium (atomic number 68)
erbium, Er
erbium (atomic number 68)
ergosphere
error
error analysis
eruption
eruptive binary star
active galaxy, eruptive galaxy
cataclysmic variable star, CV, cataclysmic binary star, eruptive variable star
einsteinium, Es
einsteinium (atomic number 99)
escape velocity
ethane
ethylene
europium, Eu
europium (atomic number 63)
europium, Eu
europium (atomic number 63)
extreme ultraviolet radiation, EUV
evaporation
event horizon
Evershed-effect, Evershed effect
evolutionary track
evolved star
mass exchange, exchange of mass
mass-exchange
excitation
exciting star
astrobiology, exobiology
exosphere
expanding envelope
expanding universe
expansion
explosion
exponential profile
exponential mass-profile
extended object
extended source
atmospheric extinction, extinction
extragalactic object
extragalactic radio source
extrasolar planet
extraterrestrial intelligence
extraterrestrial life
extreme carbon star
extreme horizontal branch star
extreme population I star
extreme ultraviolet radiation, EUV
eyepiece
florine, F
florine (atomic number 9)
Faber-Jackson distance
Faber-Jackson relation
Fabry-Perot interferometer, Fabry Perot interferometer
Fabry-Perot spectrograph, Fabry Perot spectrograph, Fabry Perot spectrometer, Fabry-Perot spectrometer
Fabry-Perot spectrograph, Fabry Perot spectrograph, Fabry Perot spectrometer, Fabry-Perot spectrometer
facula
faint blue star
faint galaxy
faint star
false color photography
Fanaroff-Riley class
fanaroff riley class
Faraday effect
Faraday rotation
far infrared radiation
far ultraviolet radiation, FUV
fast Fourier transform, FFT
fast nova
F corona, F component, F-corona
F corona, F component, F-corona
F dwarf
F dwarf star
iron, Fe
iron (atomic number 26)
feed
feed horn
Fermi-Dirac nucleus, Fermi Dirac nucleus
Fermi-Dirac statistics, Fermi Dirac statistics
Fermi interaction
fermion
fermium, Fm
fermium (atomic number 100)
Feynman diagram
Feynman integrals
fast Fourier transform, FFT
F giant
F giant star
fiber optics
fibrill
field corrector, correcting lens
field curvature, curvature of field
field equation
field galaxy
field of view
field star
figuring
filamentary nebula
filling factor
optical film, film [optical]
photographic film, film [photographic]
filter
photometry, filter photometry
filter wheel
finding chart
finding list
fine analysis
fine structure
fireball
fission
solar oscillation, five minute oscillation
FK catalog system
flare, chromospheric eruption
flare star
flash spectrum
flash star
flat field
flat field lamp
flattening
F layer, F region
flexure
florine, F
florine (atomic number 9)
flow
flow instability
fluctuation
fluid dynamics
fluid mechanics
fluorescence
flux
flux density
fermium, Fm
fermium (atomic number 100)
focal length
focal reducer
focus
Fokker-Planck equation, Fokker Planck equation
forbidden line
forbidden transition
forbush effect
force
gravitational force, force of gravity
forecasts
fork mounting
formation
element formation, formation of element
galaxy formation, formation of galaxies
star formation, formation of star
Stromgren photometry, Stromgren uvby system, four-color photometry, uvby system
Fourier analysis, harmonic analysis
Fourier component
Fourier spectrograph, Fourier spectrometer
Fourier spectrograph, Fourier spectrometer
Fourier transform
Fourier transform spectroscopy
francium, Fr
francium (atomic number 87)
fragment
fragmentation
francium, Fr
francium (atomic number 87)
Fraunhofer line
free-bound emission, free bound emission
free-free emission, free free emission
bremsstrahlung, free free transition, free-free transition
frequency
frequency analysis
frequency distribution
frequency shift
frequency standard
friction
Friedmann universe
interference fringe, fringe patterns, fringe
interference fringe, fringe patterns, fringe
frozen in element
F star
F subdwarf
F subdwarf star
F subgiant
F subgiant star
F supergiant
F supergiant star
function
fundamental chemical element
the fundamental chemical element which appear in the periodic table
physical constant, fundamental constant
fundamental frequency
fundamental mode
fundamental particle
fundamental plane
fundamental star
fundamental system
funneling
FU Orionis star
fusion
future light cone
far ultraviolet radiation, FUV
oscillator strength, f value, f-value
gallium, Ga
gallium (atomic number 31)
gadolinium, Gd
gadolinium (atomic number 64)
Galactic
Galactic anticenter, anticenter
Galactic bulge
Galactic bulge (Milky Way)
Galactic center
Galactic center (Milky Way)
Galactic cluster
Galactic open star cluster (in Milky Way)
Galactic coordinate system
Galactic cosmic ray
Galactic equator
Galactic halo
Galactic latitude
Galactic longitude
galactic nucleus
Galactic plane
Galactic plane (Milky Way)
Galactic pole
Galactic pole (Milky Way)
Galactic rotation
Galactic rotation (Milky Way)
Galactic spurs
Galactic spurs (Milky Way)
Galactic structure
Galactic structure (Milky Way)
Galactic window
Galactic window (Milky Way)
Galaxies
Galaxies: abundances
Galaxies: active
BL Lacertae objects: general
Galaxies: bulges
Galaxies: clusters: general
Cooling flows
Galaxies: distances and redshifts
Galaxies: dwarf
Galaxies: elliptical and lenticular, cD
Galaxies: evolution
Galaxies: formation
Galaxies: fundamental parameters
Galaxies: general
Galaxies: halos
Galaxies: high-redshift
Galaxies: interactions
Intergalactic medium, IGM
Galaxies: irregular
Galaxies: ISM
Galaxies: jets
Galaxies: kinematics and dynamics
Local Group
Galaxies: luminosity function, mass function
Magellanic Clouds, LMC, SMC
Galaxies: magnetic fields
Galaxies: nuclei
Galaxies: peculiar
Galaxies: photometry
Quasars: absorption lines
Quasars: emission lines
Quasars: general
Galaxies: Seyfert
Galaxies: spiral
Galaxies: starburst
Galaxies: star clusters
Galaxies: statistics
Galaxies: stellar content
Galaxies: structure
galaxy
Galaxy: abundances
Galaxy: bulge
Galaxy: center
galaxy cluster, cluster of galaxies, galaxy clustering
cluster of galaxies
galaxy cluster, cluster of galaxies, galaxy clustering
cluster of galaxies
galaxy content
galaxy count
Galaxy: disk
galaxy distribution
galaxy encounter
Galaxy: fundamental parameters
Galaxy: general
Globular clusters: general
galaxy group
group of galaxies
Galaxy: halo
Galaxy: kinematics and dynamics
galaxy merger
Galaxy: nucleus
Open clusters and associations:general
galaxy rotation curve
rotation curve of galaxy
Solar neighbourhood
Galaxy: stellar content
galaxy structure, content of galaxy, structure of galaxy
structure of galaxy
Galaxy: structure
galaxy void
galilean satellite
gallium, Ga
gallium (atomic number 31)
gamma Cassiopeiae star
gamma-ray radiation, gamma radiation, gamma-ray
gamma-ray radiation, gamma radiation, gamma-ray
gamma-ray astronomy, gamma ray astronomy
gamma-ray background, gamma ray background
gamma-ray burst, GRB, cosmic gamma ray burst, cosmic gamma-ray burst, gamma ray burst
gamma-ray line, gamma ray line
gamma-ray observatory, gamma ray observatory
gamma-ray radiation, gamma radiation, gamma-ray
Gamma rays: bursts, GRB
gamma-ray scattering, gamma ray scattering
Gamma rays: observations
gamma-ray source, gamma ray source
gamma-ray spectrograph, gamma ray spectrograph
gamma-ray spectroscopy
gamma-ray spectrum, gamma ray spectrum
Gamma rays: theory
gamma-ray telescope
gas
gas cloud
gas content
gas density
gas distribution
gas dynamics, gas kinematics
gaseous disk
gaseous discs UK
gaseous nebula
gaseous sphere
gas dynamics, gas kinematics
gas to dust ratio
G band
G-band
gadolinium, Gd
gadolinium (atomic number 64)
G dwarf
G dwarf star
germanium, Ge
germanium (atomic number 32)
gegenschein, counterglow
general theory of relativity
Geneva photometry, ubvgri photometry
geocentric orbit
geocorona
geodesy
geoid
geology
geomagnetic field
geomagnetism
geophysical observatory
geophysics, terrestrial physics
geostationary satellite
germanium, Ge
germanium (atomic number 32)
German mounting
gf value
G giant
G giant star
giant, CS star
giant star
giant branch, RGB, red giant branch
giant branch star
giant elliptical galaxy
giant galaxy
giant molecular cloud
giant planet
giant radio galaxy
glaciology
glass
optical fiber, glass fiber
glitch
sudden frequency shift
global positioning system, GPS
Globular clusters: general
globular star cluster
globule
Goedel universe
gold, Au
gold (atomic number 79)
Goulds belt
global positioning system, GPS
grading function, illumination function
grain
granulation
granule
graph
graphite
graticule
diffraction grating, grating
grating response
grating ring
grating spectrograph
gravimetry
gravitating disk
gravitating discs UK
gravitational collapse
gravitational constant
Newton's gravitational constant G
gravitational deflection
gravitational effect
gravitational energy
gravitational equilibrium
gravitational field, gravity field
gravitational force, force of gravity
gravitational instability
gravitational interaction
gravitational lens
gravitational lensing shear
gravitationally lensed source
gravitational microlensing, microlensing
microlensing
gravitational radiation
gravitational redshift
gravitational wave
Gravitational waves
graviton
gravity, acceleration of gravity
gravity anomaly
gravity darkening
gravitational field, gravity field
gravity wave
grazing incidence
grazing incidence spectrograph
grazing incidence telescope
gamma-ray burst, GRB, cosmic gamma ray burst, cosmic gamma-ray burst, gamma ray burst
Gamma rays: bursts, GRB
Great Attractor
greenhouse effect
Gregorian calendar
Gregorian telescope
grid
grism
ground-based astronomy, ground based astronomy
G star
G subdwarf
G subdwarf star
G subgiant
G subgiant star
G supergiant
G supergiant star
guide system
Gunn diode
Gunn photometry, Gunn g,r,i,z photometry
Gunn photometry, Gunn g,r,i,z photometry
g value
PG1159 star, GW Virginis star, PG1159-35 star
gyrosynchrotron radiation
negative H ion, H minus ion, H-, H- ion
negative hydrogen ion
hydrogen, H
hydrogen (atomic number 1)
hour angle, HA
hadron
hadron barrier
hafnium, Hf
hafnium (atomic number 72)
halation
half-wave dipole, half wave dipole, halfwave dipole
half-wave plate, half wave plate, halfwave plate
halo
halo star
H alpha
H alpha (656 nm)
H alpha emission line star
H alpha photometry
H and K line
Hanle effect
Harman-Seaton sequence, Harman Seaton sequence
Fourier analysis, harmonic analysis
harmonic frequency, harmonic overtones, harmonics
overtone frequency, harmonic overtones, overtones
harmonic frequency, harmonic overtones, harmonics
harmonic frequency, harmonic overtones, harmonics
Haro galaxy
Hartmann test
Henry Draper system, HD system, Harvard classification
Henry-Draper system
hassium, Hs
hassium (atomic number 108)
Hawking radiation
Hayashi track
Stars: horizontal-branch, HB
H beta
H beta (486 nm)
H beta photometry
Hickson compact group, HCG
Hickson compact group of galaxies
HD curve
H delta
H delta (410 nm)
Henry Draper system, HD system, Harvard classification
Henry-Draper system
helium, He
helium (atomic number 2)
head tail galaxy
heat-transfer
heat transfer
heavy element
heavy metal star
He I
neutral helium
height, elevation
altitude [height]
He II
once-ionized helium
He III
twice-ionized helium
He II ionization zone, He+ ionisation zone UK, He+ ionization zone
He II ionization zone, He+ ionisation zone UK, He+ ionization zone
He II ionization zone, He+ ionisation zone UK, He+ ionization zone
heliocentric correction
heliocentric Julian Date, H.J.D., HJD
heliocentric orbit
annual parallax, heliocentric parallax, parallax
heliocentric velocity
heliograph
heliometer
heliopause
helioseismology, solar seismology
heliosphere
heliostat
helium, He
helium (atomic number 2)
helium burning
helium flash, helium detonation
helium flash, helium detonation
helium-poor star, helium poor star
helium-rich star, helium rich star
helium shell flash
SX Arietis star, helium variable star
Helmholtz-Kelvin contraction, Helmholtz Kelvin contraction, Kelvin-Helmholtz contraction
Henry Draper catalog
Henry Draper system, HD system, Harvard classification
Henry-Draper system
Henyey track
H epsilon
Herbig AeBe star, Herbig Ae-Be star, Herbig star
Herbig-Haro object, HH-object
Herbig-Haro objects
Herbig AeBe star, Herbig Ae-Be star, Herbig star
Hertzsprung gap
Hertzsprung-Russell and C-M diagrams, Color-Magnitude diagrams, H-R and C-M diagrams, H-R and CM diagrams, HR and C-M diagrams, HR and CM diagrams, Hertzsprung-Russel and Color-Magnitude diagrams, Hertzsprung-Russel diagrams
Hertzsprung-Russell and C-M diagrams, Color-Magnitude diagrams, H-R and C-M diagrams, H-R and CM diagrams, HR and C-M diagrams, HR and CM diagrams, Hertzsprung-Russel and Color-Magnitude diagrams, Hertzsprung-Russel diagrams
Hertzsprung-Russell and C-M diagrams, Color-Magnitude diagrams, H-R and C-M diagrams, H-R and CM diagrams, HR and C-M diagrams, HR and CM diagrams, Hertzsprung-Russel and Color-Magnitude diagrams, Hertzsprung-Russel diagrams
Hertzsprung-Russell diagram, HR diagram, Hertzsprung Russell diagram
Hess diagram
heterodyne
hafnium, Hf
hafnium (atomic number 72)
mercury, Hg
mercury (atomic number 80)
H gamma
H gamma (434 nm)
Herbig-Haro object, HH-object
H I, neutral hydrogen
H I absorption
Hickson compact group, HCG
Hickson compact group of galaxies
H I cloud
H I content
H I emission
hierarchical cosmology
high-resolution spectrosopy, high dispersion spectroscopy, high resolution spectrosopy, high-dispersion spectroscopy
high-resolution spectrum, high dispersion spectrum, high resolution spectrum, high-dispersion spectrum
high-energy astrophysics, high energy astrophysics, high energy process, high-energy process
high-energy astrophysics, high energy astrophysics, high energy process, high-energy process
high-energy radiation, high energy radiation
high-luminosity star, high luminosity star, luminous star
high-mass star
high-mass X-ray binary star
high-resolution spectrosopy, high dispersion spectroscopy, high resolution spectrosopy, high-dispersion spectroscopy
high-resolution spectrum, high dispersion spectrum, high resolution spectrum, high-dispersion spectrum
high-speed photometer, high speed photometer
high-state
photometric high state of variable object
high-temperature, high temperature, hot
high-velocity cloud, HVC, high velocity cloud
high-velocity star, high velocity star
H II, ionized hydrogen
H II region, HII region
HII regions
negative H ion, H minus ion, H-, H- ion
negative hydrogen ion
Hirayama family
H I region
history of astronomy
heliocentric Julian Date, H.J.D., HJD
H line
H magnitude
negative H ion, H minus ion, H-, H- ion
negative hydrogen ion
holmium, Ho
holmium (atomic number 67)
Holmberg radius
holmium, Ho
holmium (atomic number 67)
holmium star
Holtsmark approximation
horizon
horizon coordinate system
horizontal branch star
horizontal parallax
horn antenna, horn antennas
horn antenna, horn antennas
horseshoe mounting
high-temperature, high temperature, hot
early-type star, blue star, early type star, hot star
hour angle, HA
Hertzsprung-Russell and C-M diagrams, Color-Magnitude diagrams, H-R and C-M diagrams, H-R and CM diagrams, HR and C-M diagrams, HR and CM diagrams, Hertzsprung-Russel and Color-Magnitude diagrams, Hertzsprung-Russel diagrams
Hertzsprung-Russell diagram, HR diagram, Hertzsprung Russell diagram
hassium, Hs
hassium (atomic number 108)
Hubble Space Telescope, HST
HST photometry, HST Fnnn[LMNW] photometry, Hubble photometry
HST photometry, HST Fnnn[LMNW] photometry, Hubble photometry
Hubble Sandage variable star, H S variable star, H-S variable star
Hubble-Sandage variable star
Hubble classification, Hubble sequence
Hubble constant
Hubble diagram
Hubble law
HST photometry, HST Fnnn[LMNW] photometry, Hubble photometry
Hubble radius
Hubble Sandage variable star, H S variable star, H-S variable star
Hubble-Sandage variable star
Hubble classification, Hubble sequence
Hubble Space Telescope, HST
Hubble time
high-velocity cloud, HVC, high velocity cloud
hydrated carbon, CH
CH molecule
hydrocarbon
hydrogen, H
hydrogen (atomic number 1)
hydrogen burning
hydrogen deficient star
hydrogen-deficient star
hydrogen line
hydrogen spectrum
magnetohydrodynamics, MHD, hydromagnetics
Alfven wave, hydromagnetic wave
hydrostatic equilibrium
hydroxyl radical, OH, OH radical
hyperbolic orbit
hyperfine line
hypergalaxy
hypergiant
hypergiant star
hypernova
hypothetical planet
HZ Herculis star
iodine, I
iodine (atomic number 53)
water ice, ice
identification
I galaxy
irregular galaxy (Yerkes classification scheme)
Intergalactic medium, IGM
illumination
grading function, illumination function
image
image tube, image converters, image intensifier, light amplifier, photoelectric image tube
image tube, image converters, image intensifier, light amplifier, photoelectric image tube
image processing
image reconstruction
image tube, image converters, image intensifier, light amplifier, photoelectric image tube
imaging instrument
I magnitude
initial mass function, IMF
impact crater
impersonal astrolabe
indium, In
indium (atomic number 49)
inclination
indium, In
indium (atomic number 49)
indochinite
inertial coordinate system
inertial reference frame
inflationary universe
infrared
infrared astronomy
infrared detector
infrared emission
Infrared: galaxies
infrared galaxy
Infrared: general
Infrared: ISM
infrared observatory
infrared photometry
infrared radiation
Infrared: solar system
infrared source
Infrared: stars
infrared telescope
infrared transmission window
infrared transmission window through the atmosphere
inhomogenity
initial mass function, IMF
inner core
inner planet, terrestrial planet
Instabilities
instability
instability strip
instrument, astronomical instrument, instrumentation
instrumental profile
instrument, astronomical instrument, instrumentation
Instrumentation: adaptive optics
Instrumentation: detectors
Instrumentation: high angular resolution
Instrumentation: interferometers
Instrumentation: miscellaneous
Instrumentation: photometers
Instrumentation: polarimeters
Instrumentation: spectrographs
integral field spectrograph
integrated magnitude, total magnitude
integration time
intensity, specific intensity
intensity interferometer
interacting binary star
interacting galaxy
interaction
intercloud gas
intercloud matter
interference filter
interference fringe, fringe patterns, fringe
interference noise
interference [noise]
interference spectrosocopy
interference wave
interference [wave]
interferometer
interferometric correlation
interferometry
intergalactic absorption
intergalactic cloud
intergalactic gas
intergalactic matter
Intergalactic medium, IGM
intergalactic space
interior
intermediate population star
intermediate type star
internal motion
interplanetary dust
interplanetary gas
interplanetary grain
interplanetary magnetic field
interplanetary matter, interplanetary medium
interplanetary matter, interplanetary medium
Interplanetary medium
interplanetary scintillation
interstellar absorption, interstellar extinction
interstellar bubble
interstellar communication
interstellar dust
interstellar absorption, interstellar extinction
interstellar gas
interstellar magnetic field
interstellar matter, interstellar medium
interstellar matter, interstellar medium
Interstellar medium, nebulae, ISM, nebulae
interstellar molecule
interstellar reddening
interstellar scintillation
interstellar wind
intracluster matter
intrinsic color
intrinsic variable star, unstable star
inverse Compton effect
inverse Compton scattering
inverse maser
iodine, I
iodine (atomic number 53)
iodine cell
ion, charged particle
ion composition
ion density
ionization, ionisation UK
ionization equilibrium, ionisation equilibrium UK
ionization, ionisation UK
ionization equilibrium, ionisation equilibrium UK
ionized gas
H II, ionized hydrogen
ionizing shock wave
ionosphere
ionospheric scintillation
ion plasma wave
ion temperature
iridium, Ir
iridium (atomic number 77)
IRAS satellite, IRAS
InfraRed Astronomical Satellite
IRAS galaxy
IRAS satellite, IRAS
InfraRed Astronomical Satellite
iridium, Ir
iridium (atomic number 77)
iron, Fe
iron (atomic number 26)
iron meteorite
irradiance
irregular galaxy
irregular variable star
ISM: abundances
ISM: atoms
ISM: bubbles
ISM: clouds
Cosmic rays
Dust, extinction
Evolution
ISM: general
Herbig-Haro objects
HII regions
ISM: jets and outflows
ISM: kinematics and dynamics
ISM: lines and bands
ISM: magnetic fields
ISM: molecules
Interstellar medium, nebulae, ISM, nebulae
Planetary nebulae: general, PN
Reflection nebulae
ISM: structure
ISM: supernova remnants, SNR
isophot
isophotal diameter
isothermal sphere
isothermal mass-profile
isotope
isotopic abundance
isotopic composition
isotropy
Jansky
Julian Date, J.D., JD
Jeans length
Jeans mass
jet, astrophysical jet
J magnitude
Johnson photometry, Johnson-Morgan filter system, UBV photometry, UBVRI photometry, UBVRIJKL photometry, three-color photometry
Johnson noise
Johnson photometry, Johnson-Morgan filter system, UBV photometry, UBVRI photometry, UBVRIJKL photometry, three-color photometry
Jovian planet
Julian calendar
Julian Date, J.D., JD
Julian epoch
jump condition
Jupiter
potassium, K
potassium (atomic number 19)
kappa mechanism
Kapteyn selected area
Edgeworth-Kuiper belt object, EKO, KBO, Kuiper belt object
K corona, K-corona
k correction, k-term
k-correction
K dwarf
K dwarf star
Kellner eyepiece
Kelvin
Helmholtz-Kelvin contraction, Helmholtz Kelvin contraction, Kelvin-Helmholtz contraction
Kelvin timescale
Keplerian orbit
Kerr black hole
K giant
K giant star
kinematic parallax
kinematics
kinetic energy
Kirkwood gap
K line
K magnitude
krypton, Kr
krypton (atomic number 36)
Kramers opacity
Kreutz sungrazer, sungrazer
Kron-Cousins photometry, Kron Cousins photometry, Kron-Cousins R,I photometry
Kron-Cousins photometry, Kron Cousins photometry, Kron-Cousins R,I photometry
Kruskal diagram
krypton, Kr
krypton (atomic number 36)
K star
K subdwarf
K subdwarf star
K subgiant
K subgiant star
K supergiant
K supergiant star
k correction, k-term
k-correction
Edgeworth-Kuiper belt object, EKO, KBO, Kuiper belt object
lanthanum, La
lanthanum (atomic number 57)
Lagrangian point, libration point
cosmological constant, Lambda
lambda eridani star
lamp
lanthanum, La
lanthanum (atomic number 57)
Large Magellanic Cloud, LMC
large scale structure
Large-scale structure of Universe
laser
laser ranging
late-type dwarf, cool dwarf star, late type dwarf star
late-type dwarf star
late-type dwarf, cool dwarf star, late type dwarf star
late-type dwarf star
late-type galaxy, late type galaxy
late-type giant, cool giant star, late type giant star
late-type giant star
late-type giant, cool giant star, late type giant star
late-type giant star
late-type star, cool star, late type star
late-type subdwarf, cool subdwarf star
late-type supergiant, cool supergiant star
late-type supergiant star
late-type variable star
latitude
latitude determination
latitude variation
lawrencium, Lr
lawrencium (atomic number 103)
Lb variable star
Lc variable star
L dwarf
lead, Pb
lead (atomic number 82)
Lemaitre universe
lens
lens antenna, lens antennas
lens antenna, lens antennas
lens design
lenticular galaxy, S0 galaxy
lepton
L galaxy
low surface-brightness galaxy (Yerkes classification scheme)
lithium, Li
lithium (atomic number 3)
libration, physical libration
Lagrangian point, libration point
life
visible radiation, light
light absorption
image tube, image converters, image intensifier, light amplifier, photoelectric image tube
light coherence
light cone
light curve
light emission
light interference
optical interferometry, light interferometry, stellar interferometry
light polarization, polarization wave
light scattering
light year
limb brightening
limb darkening
limiting magnitude
linearity calibration
plane polarization, linear polarization, plane polarisation UK
line blanketing
line blending
line blocking
line broadening, spectral line broadening
line intensitite
node, line of node
line of sight
line-of-sight
line profile
Line: profiles
line ratio
liner galaxy
line shift, spectral line shift
line spectrum
Zeeman splitting, line splitting, spectral line splitting
line width, spectral line width
lithium star, Li star, lithium rich star, lithium-rich star
lithium, Li
lithium (atomic number 3)
lithium-poor star, lithium poor star
lithium star, Li star, lithium rich star, lithium-rich star
lithium star, Li star, lithium rich star, lithium-rich star
lithosphere
L magnitude
low-mass X-ray binary star, LMXB
lobe
sidelobe, lobe [telescope beam]
Local Standard of Rest, LSR, L.S.R.
Local Supercluster
Local Supercluster of galaxies
local thermodynamic equilibrium, LTE
location
having to do with cosmic location
location behind
location behind something else
location between
location in front
location in front of something else
log g value
log(g) value
long baseline interferometer
long baseline interferometry
longitude
long period comet
long period variable star
long slit
long slit spectrum
loop
low-luminosity star, low luminosity star
low-mass star, low mass star
low-mass X-ray binary star, LMXB
low-state
photometric low state of variable object
low-temperature plasma
low temperature plasma
lawrencium, Lr
lawrencium (atomic number 103)
Local Standard of Rest, LSR, L.S.R.
L subdwarf
local thermodynamic equilibrium, LTE
lutetium, Lu
lutetium (atomic number 71)
luminescence, candoluminescence
luminosity
luminosity class
luminosity classification
luminosity-dispersion relation
luminosity distribution
luminosity function
luminous arc
luminous arc produced by gravitational lensing
luminous blue variable star
high-luminosity star, high luminosity star, luminous star
lunar
lunar dome
lunar eclipse
lunar laser ranging
lunar occultation
occultation by the Moon
lunar phase, phase Moon
phase of the Moon
lunar theory
lutetium, Lu
lutetium (atomic number 71)
Lyman alpha
Lyman alpha forest
Lyman beta
Lyman continuum
Lyman series
macro spicule
macroturbulence
Magellanic cloud, Clouds of Magellan
Magellanic Clouds, LMC, SMC
Magellanic stream
magnesium, Mg
magnesium (atomic number 12)
magnetar
magnetic anomaly
magnetic disturbances
magnetic field
Magnetic fields
magnetic monopole
magnetic pole
magnetic property
magnetic star, cobalt star
magnetic storm
magnetic variable star
magnetograph
magnetoheliograph
magnetohydrodynamics, MHD, hydromagnetics
MHD, Magnetohydrodynamics
magneto-optical effect, magneto optical effect
magnetosphere
magnetospheric substorm
magnitude
main sequence
main sequence star
major axis
Maksutov telescope
manganese, Mn
manganese (atomic number 25)
manganese star
mantle
N-body problem, N body problem, many body problem, many-body problem
map
maria
Markarian galaxy
Mars
mascon
maser
Masers
mass
mass density
mass-density
mass distribution
mass-loss, mass loss, mass-ejection
mass exchange, exchange of mass
mass-exchange
mass flow
mass-flow
mass function
mass-function
massive galaxy
massive object
massive star
mass-loss, mass loss, mass-ejection
mass-luminosity relation, mass luminosity relation
mass-radius relation, mass radius relation
mass-ratio, mass ratio
mass to light ratio
mass-to-light ratio
mass-transfer, mass transfer
mathematical analysis
mathematical model
mathematics
matter
Maunder minimum
maximum
maximum entropy method
mendelevium, Md
mendelevium (atomic number 101)
M dwarf
M dwarf star
mean anomaly
mean equinox
mean solar time
measurement
measuring instrument
mechanical component
mechanical property
medium band photometry
medium-band photometry
megalithic astronomy
megamaser
meitnerium, Mt
meitnerium (atomic number 109)
mendelevium, Md
mendelevium (atomic number 101)
mercury, Hg
mercury (atomic number 80)
mercury, Hg
mercury (atomic number 80)
mercury manganese star
merger
meridian
meridian circle
meridian observation
meson
mesopause
mesosphere
Me star
metagalaxy
metal abundance, metallicity
metal-deficient star
metal abundance, metallicity
metal-rich star, metallic line star
metal rich star
metal line
metal-poor star, metal poor star
metal-rich star, metallic line star
metal rich star
meteor
meteor camera
meteoroid, meteorids
meteorite
meteorite crater
meteorite impact
meteoroid, meteorids
meteoroid dust cloud
meteorology
meteor shower
Meteors, meteoroids
meteor stream
meteor trail
methane, CH4, CH_4
methane molecule
observing technique, method of observation
Methods: analytical
Methods: data analysis
Methods: laboratory
Methods: miscellaneous
Methods: N-body simulations
Methods: numerical
Methods: observational
Methods: statistical
metonic cycle
metrology
Me variable star
magnesium, Mg
magnesium (atomic number 12)
M giant
M giant star
Michelson interferometer
Michelson interferometry
microchannel plate
micro-channel plate
microdensitometer
microdensitometry
gravitational microlensing, microlensing
microlensing
micrometeorite
micrometeoroid
micrometer
microphotometer
microprocessor
microturbulence
microwave
microwave antenna, microwave antennas
microwave antennaa
microwave antenna, microwave antennas
microwave antennaa
microwave background
cosmic microwave background
microwave emission
microwave imaging
microwave radiation
microwave spectroscopy
microwave spectrum
Mie scattering
Milky Way galaxy, the Galaxy
the Milky Way galaxy
millimeter astronomy
millimeter radiation, millimeter wave, mm radiation
millimeter radiation, millimeter wave, mm radiation
Mills cross antenna, Mills cross antennas
Mills cross antenna, Mills cross antennas
Milne Eddington approximation
mineral deposit
mineralogy
minimum
minor axis
asteroid, minor planet, planetoid
minor planet family
Minor planets, asteroids
Mira variable star, Miras, omicron Ceti star, zeta Aurigae star
Mira variable star, Miras, omicron Ceti star, zeta Aurigae star
mirror
mirror cell
missing mass
MK classification
M magnitude
millimeter radiation, millimeter wave, mm radiation
multiple mirror telescope, MMT
manganese, Mn
manganese (atomic number 25)
molybdenum, Mo
molybdenum (atomic number 42)
model
MOdified Newtonian Dynamics, MOND
modulation
modulation transfer function, MTF
distance modulus, modulus
moldavite
molecular astrophysics
molecular band
molecular cloud
Molecular data
molecular hydrogen
molecular line
Molecular processes
molecular spectroscopy
molecular spectrum
molecule
molybdenum, Mo
molybdenum (atomic number 42)
momentum
MOdified Newtonian Dynamics, MOND
monochromator
Monte Carlo technique
moonquake
morphology
motion
mottle
moving cluster parallax, cluster parallax
m region
M star
M subdwarf
M subdwarf star
M subgiant
M subgiant star
M supergiant
M supergiant star
meitnerium, Mt
meitnerium (atomic number 109)
modulation transfer function, MTF
multi-channel detector, multichannel detector
multi-channel spectrograph, multi-channel spectrometer, multichannel spectrograph
multi-channel spectrograph, multi-channel spectrometer, multichannel spectrograph
multi-color photometry, multicolor photometry
multi-fiber spectrograph
multi-periodic pulsation, multiperiodic pulsation
multi-periodic variable star, multiperiodic variable star
multiple galaxy
multiple mirror telescope, MMT
multiple star
multi-slit spectrograph
muon
nitrogen, N
nitrogen (atomic number 7)
sodium, Na
sodium (atomic number 11)
nadir
naked singularity
narrow band photometry
narrow-band photometry
Nasmyth focus
natural line broadening
natural line width
nautical almanac
Navarro-Frenk-White profile, NFW, NFW profile, NFW-profile
Navarro-Frenk-White mass-profile
niobium, Nb
niobium (atomic number 41)
N-body problem, N body problem, many body problem, many-body problem
N-body simulation
North Celestial Pole, NCP, N.C.P.
neodymium, Nd
neodymium (atomic number 60)
neon, Ne
neon (atomic number 10)
nearby dwarf
nearby dwarf star
nearby galaxy
nearby star
near-Earth asteroid, NEO, near Earth asteroid, near-Earth object
near-Earth asteroid, NEO, near Earth asteroid, near-Earth object
near infrared radiation
near ultraviolet radiation, NUV
nebula
nebular filament
negative H ion, H minus ion, H-, H- ion
negative hydrogen ion
neighborhood
near-Earth asteroid, NEO, near Earth asteroid, near-Earth object
neodymium, Nd
neodymium (atomic number 60)
neon, Ne
neon (atomic number 10)
North Ecliptic Pole, NEP, N.E.P.
Neptune
neptunium, Np
neptunium (atomic number 93)
Neumann line
neutral density filter
neutral gas
H I, neutral hydrogen
neutrino
Neutrinos
neutron
neutron star
Newtonian focus
Newtonian gravitation
Newtonian telescope
Navarro-Frenk-White profile, NFW, NFW profile, NFW-profile
Navarro-Frenk-White mass-profile
Navarro-Frenk-White profile, NFW, NFW profile, NFW-profile
Navarro-Frenk-White mass-profile
N galaxy
North Galactic Pole, NGP, N.G.P.
nickel, Ni
nickel (atomic number 28)
nickel, Ni
nickel (atomic number 28)
airglow, dayglow, nightglow
night sky brightness, night sky background
night sky brightness, night sky background
night vision
niobium, Nb
niobium (atomic number 41)
nitrogen, N
nitrogen (atomic number 7)
N magnitude
nobelium, No
nobelium (atomic number 102)
nobelium, No
nobelium (atomic number 102)
noctilucent cloud
node, line of node
noise
nomenclature
non-equilibrium flow, nonequilibrium flow
non-LTE transfer, nonLTE transfer
non-main sequence star, nonmain_sequence star
non-main_sequence star
non-radial pulsation, nonradial pulsation
non-thermal particle, nonthermal particle
non-thermal radiation, nonthermal radiation
non-thermal source, nonthermal source
North Celestial Pole, NCP, N.C.P.
North Ecliptic Pole, NEP, N.E.P.
northern hemisphere
North Galactic Pole, NGP, N.G.P.
Novae, cataclysmic variables, CV
nova-like variable
slow nova, novoid
neptunium, Np
neptunium (atomic number 93)
Stars: neutron, NS
N star
nuclear astrophysics
nuclear fission
nuclear fusion
nuclear physics
nuclear radiation
nuclear reaction
Nuclear reactions, nucleosynthesis, abundances
cosmochronology, nucleocosmochronology
nucleosynthesis
nucleus atom
nucleus [atom]
nucleus celestial object
nucleus [celestial object]
numerical analysis
numerical integration
numerical method
numerical simulation
nutation
near ultraviolet radiation, NUV
oxygen, O
oxygen (atomic number 8)
O association, O-association
OB association
objective
objective [optics]
objective grating
objective prism
oblateness
oblique rotator
obliquity of ecliptic, obliquity
obliquity of ecliptic, obliquity
observation
observational cosmology
observatory
observing technique, method of observation
OB star
OB supergiant
OB supergiant star
occultation
Occultations
occulting disk
occulting disc UK
oceanography
ocean tide
O cluster
O-star cluster
O dwarf
O dwarf star
Oef star
Oe star
Of star
O giant
O giant star
hydroxyl radical, OH, OH radical
OH absorption
OH cloud
OH emission
OH IR star, OH-IR star
OH/IR star
OH line
OH maser
hydroxyl radical, OH, OH radical
OH source
old star
O magnitude
Omega baryon, Omega(baryon)
Omega(baryon), the cosmological baryon mass-density fraction
Omega Lambda, Omega(Lambda)
Omega(Lambda), the cosmological vacuum energy density fraction
Omega mass, Omega(mass)
omega(mass), the cosmological matter density fraction
Omega parameter
the cosmological density fraction parameter, Omega
Mira variable star, Miras, omicron Ceti star, zeta Aurigae star
on-line system, on line system
Oort cloud, Oort comet cloud
Oort constant
Oort formulae, Oort formulas
Oort formulae, Oort formulas
Oosterhoff group
opacity
Open clusters and associations:general
open star cluster
open universe
Opik theory
opposition
optical aberration, aberration
aberration of optical image
optical burst
optical component
optical identification, optical counterparts
optical depth, optical thickness
optical design
optical double star
apparent optical double star
optical instrument, optical equipment
optical fiber, glass fiber
optical film, film [optical]
optical filter, color filter
optical flare
optical glass
optical identification, optical counterparts
optical instrument, optical equipment
optical interferometer, stellar interferometer
optical interferometry, light interferometry, stellar interferometry
optical material
optical observation
optical observatory
optical outburst
optical pathlength
optical position
optical property
optical pulsar
optical radar
optical scanners
optical spectrograph, optical spectrometer
optical spectrograph, optical spectrometer
optical spectroscopy
optical surface
optical system
optical telescope
optical testing
optical depth, optical thickness
optical transfer function, OTF
optical transmission window
optical transmission window through the atmosphere
optical waveguide
optical window
optical window [optics]
optics
orbit
orbital anomaly, apparent anomaly
orbital_anomaly
orbital element
orbital evolution
orbital motion
orbital theory
orbital velocity
orbit determination
space observatory, orbiting observatory
organic matter
organic molecule
orientation
origin
orion population star
orrery
orthohydrogen
orthoscopic eyepiece
osmium, Os
osmium (atomic number 76)
oscillating universe
oscillation
oscillator strength, f value, f-value
osculating orbit
osculatory element
osmium, Os
osmium (atomic number 76)
O star
O subdwarf
O subdwarf star
O supergiant
O supergiant star
optical transfer function, OTF
outburst
outer planet
outgassing
overabundance
overtone frequency, harmonic overtones, overtones
overtone mode, overtones
oxygen, O
oxygen (atomic number 8)
oxygen burning
ozone layer
phosphorus, P
phosphorus (atomic number 15)
protactinium, Pa
protactinium (atomic number 91)
pair annihilation
pair production
paleomagnetism
palladium, Pd
palladium (atomic number 46)
parabolic antenna, parabolic antennas
parabolic antenna, parabolic antennas
parabolic mirror
parabolic orbit
parabolic reflector
parabolic velocity
parahydrogen
parsec, parallax second
parallel computer
parametric amplifier
parsec, parallax second
partial eclipse
particle
particle acceleration
particle accretion
particle beam
particle creation
particle escape
particle interaction
particle production
particle propagation
Paschen-Back effect
Paschen series, Paschen line
Paschen series, Paschen line
past light cone
Paul trap
lead, Pb
lead (atomic number 82)
p branch
p-branch
P Cygni line profile
S Doradus star, P Cygni star
palladium, Pd
palladium (atomic number 46)
Ap star, peculiar A star
peculiar galaxy
peculiar giant
peculiar giant star
peculiar motion
peculiar object
peculiar star
peculiar variable star
peculiar velocity
pencil beam
pendulum
Penrose process
penumbra, penumbras
penumbral filament
penumbra, penumbras
periapsis
periastron
pericenter
perigee
perihelion
period
period-age relation, period age relation
period change, period variation
period-color relation, period color relation
period-density relation, period density relation
period determination
periodic comet
periodic orbit
periodic variable star
period-luminosity-color relation, PLC relation, period luminosity color relation
period-luminosity relation, PL relation, period luminosity relation
period-mass relation, period mass relation
period-radius relation, period radius relation
period-spectrum relation, period spectrum relation
period change, period variation
peripheral
perturbation
perturbation theory
petrology
Pfund series
PG1159 star, GW Virginis star, PG1159-35 star
PG1159 star, GW Virginis star, PG1159-35 star
phase angle
phased array
phase defect
phase difference
phase effect
phase error
phase function
lunar phase, phase Moon
phase of the Moon
phase rotator
phase sensitive detector
phase shift, phase-shift
phase space
phase switching
phase switching interferometer
phase wave
phase of a repeating wave
Phillips band
phosphorescence
phosphorescent scintillation
phosphorus, P
phosphorus (atomic number 15)
photocathode
photomultiplier tube, photocell, photoelectric cell
photochemistry
photoconductive cell
photodiode
photodissociation
photomultiplier tube, photocell, photoelectric cell
image tube, image converters, image intensifier, light amplifier, photoelectric image tube
photoelectric instrument
photoelectric magnitude
photoelectric photometer
photoelectric photometry
photoelectronic device
photogrammetry
photograph
photographic astrometry
photographic developer
photographic emulsion
photographic film, film [photographic]
photographic filter
photographic instrument
photographic magnitude
photographic material
photographic photometry
photographic plate
photographic processing
zenith tube, photographic zenith tube
photography, astrophotography
photoheliograph
photoionization, photoionisation UK
photoionization, photoionisation UK
photoluminescence
photometer
ellipsoidal variable star, ellipsoidal binary star, photometric binary star
eclipsing binary star, eclipsing star, eclipsing variable star, photometric binary star
photometric element
photometric parallax
photometric standard star
photometric system
photometry, filter photometry
photomultiplier tube, photocell, photoelectric cell
photon
photon counting system
photosphere, reversing layer
photovisual magnitude
photovoltaic cell
physical constant, fundamental constant
Physical data and processes
libration, physical libration
pixel, picture element, voxel
pion
pitch angle
pixel, picture element, voxel
plage
flocculi
solar plage
Planck black body formula
Planck constant
Planck's constant h
plane polarization, linear polarization, plane polarisation UK
plane polarization, linear polarization, plane polarisation UK
planet
planetar
planetarium
planetary
planetary alignment
alignment of planet, etc.
planetary microlensing
microlensing of exoplanet
planetary nebula
Planetary nebulae: general, PN
planetary ring
planetary system
Planetary systems
Planetary systems: formation
Planetary systems: protoplanetary disks, proplyd
planetary theory
planetesimal
asteroid, minor planet, planetoid
planetology
Planets and satellites: formation
Planets and satellites: general
planet satellite
Planets: rings
plasma, cosmic plasma
plasma cloud
plasma jet
plasma loop
plasmapause
plasma physics
Plasmas
plasma wave
platinum, Pt
platinum (atomic number 78)
period-luminosity-color relation, PLC relation, period luminosity color relation
period-luminosity relation, PL relation, period luminosity relation
Pluto
plutonium, Pu
plutonium (atomic number 94)
promethium, Pm
promethium (atomic number 61)
P magnitude
Stars: pre-main sequence, PMS
Planetary nebulae: general, PN
polonium, Po
polonium (atomic number 84)
Pogson scale
Poincare theorem
pointing accuracy
pointing error
point spread function, PSF
polar axis
polar cap
polar diagram
polarimeter
polarimetry
polarized light, polarised light UK
Polarization
polarization charge separation
polarization [charge separation]
light polarization, polarization wave
polarized light, polarised light UK
polarized radiation
polar motion
polar orbit
polar region
AM Herculis star, polars
polar tide
Chandler wobble, polar wandering
pole
polishing
pollution
polonium, Po
polonium (atomic number 84)
polycyclic hydrocarbon
polytrope
population I star, PopI
population II star, Pop II star, PopII
population III star, PopIII
population II star, Pop II star, PopII
population II Cepheid
population III star, PopIII
population II star, Pop II star, PopII
population inversion
population I star, PopI
position
astrometry, positional astronomy
position angle
position sensitive proportional counter, PSPC
position-sensitive proportional counter
positron
post-asymptotic giant branch, post-AGB
Stars: AGB and post-AGB, AGB, post-AGB
post-asymptotic giant branch, post-AGB
post-main sequence star, post main sequence star
potassium, K
potassium (atomic number 19)
potential energy
potential theory
power
Poynting-Robertson effect, Poynting Robertson effect
p process
p-process
praseodymium, Pr
praseodymium (atomic number 59)
praseodymium, Pr
praseodymium (atomic number 59)
preamplifier
precession
precision
precursor pulse
progenitor, precursors
prediction
pre-Galactic star, pregalactic star
pre-main sequence star, early stage star, premainsequence star
pre-nova, prenova
pre-solar nebula, presolar nebula
pressure
pressure broadening
pre-supernova, presupernova
cosmic ray, cosmic radiation, primary cosmic ray
primary lens
primary mirror
primary star
prime focus
primordial fireball
primordial galaxy
prism
prism spectrograph
space probe, probe
profile
progenitor, precursors
promethium, Pm
promethium (atomic number 61)
prominence, chromospheric eruption
propagation
proper motion
property
Planetary systems: protoplanetary disks, proplyd
protoplanetary nebula, proplyds
proportional counter
protactinium, Pa
protactinium (atomic number 91)
protocluster
protogalaxy
proton
proton-proton reaction, proton proton cycle, proton proton reaction, proton-proton cycle
proton-proton reaction, proton proton cycle, proton proton reaction, proton-proton cycle
protoplanet
protoplanetary nebula, proplyds
protostar
point spread function, PSF
position sensitive proportional counter, PSPC
position-sensitive proportional counter
platinum, Pt
platinum (atomic number 78)
plutonium, Pu
plutonium (atomic number 94)
pulsar
Pulsars: general
pulsating variable star
pulsation
pulsation mode
pulsation theory
pulse
pulse counter
pulse counting
pulse duration
pulse energy
pulse intensity
pulse profile
pulse structure
pulse width
pulse window
Purkinje effect
q branch
q-branch
quantum efficiency, Q.E., QE
Q magnitude
deceleration parameter, q-parameter
quasar, QSO, quasi-stellar galaxy, quasi-stellar object, quasi-stellar radio_source
quadrant
quadrant detector
quadrature
quanta, quantum
quantization, quantisation UK
quantization, quantisation UK
quanta, quantum
quantum cosmology
quantum efficiency, Q.E., QE
quantum field theory
quantum mechanics
quantum theory
quark
quarter wave plate
quarter-wave plate
quasar, QSO, quasi-stellar galaxy, quasi-stellar object, quasi-stellar radio_source
quasar galaxy pair
quasar-galaxy pair
quasar microlensing
microlensing of AGN nucleus
Quasars: absorption lines
Quasars: emission lines
Quasars: general
quasar, QSO, quasi-stellar galaxy, quasi-stellar object, quasi-stellar radio_source
quasar, QSO, quasi-stellar galaxy, quasi-stellar object, quasi-stellar radio_source
quasar, QSO, quasi-stellar galaxy, quasi-stellar object, quasi-stellar radio_source
quiescent prominence
quiet Sun
radium, Ra
radium (atomic number 88)
radar
radar astronomy
radar equipment
radar mapping
radar telescope
radial pulsation
radial velocity
radiant meteor
radiant [meteor]
radiant moving cluster
radiant [moving cluster]
radiation
background radiation, radiation background
radiation belt
radiation damping
radiation field
radiation mechanism
Radiation mechanisms: general
Radiation mechanisms: non-thermal
Radiation mechanisms: thermal
radiation pressure
radiation scattering, electromagnetic wave scattering
radiative braking
radiative recombination, radiative capture
radiative equilibrium
radiative recombination, radiative capture
radical
radio absorption
radioactive decay
radioactivity
radio antenna, radio antennas
radio antennas
radio antenna, radio antennas
radio antennas
radio astrometry
radio astronomy
radio background, radio frequency interference, radio noise
radio burst
Radio continuum: galaxies
Radio continuum: general
Radio continuum: ISM
Radio continuum: solar system
Radio continuum: stars
radio core
radio emission
radio flare
radio frequency
radio interference, radio frequency interference, radio noise
radio background, radio frequency interference, radio noise
radio galaxy
radioheliograph
radio interference, radio frequency interference, radio noise
radio interferometer
radio interferometry
radio jet
Radio lines: galaxies
Radio lines: general
Radio lines: ISM
Radio lines: solar system
Radio lines: stars
radiometer
radiometry
radio interference, radio frequency interference, radio noise
radio background, radio frequency interference, radio noise
radio observatory
radio occultation
radio pulsar
radio quiet quasar
radio radiation, radio wave
radio recombination line
radio source
radio source catalog
radio source count
radio spectrograph, radio spectrometer
radio spectrograph, radio spectrometer
radio spectroscopy
radio spectrum
radio star
radio structure
radio telescope
radio transmission window
radio transmission window through the atmosphere
radio radiation, radio wave
radio waveguide
radium, Ra
radium (atomic number 88)
radius-luminosity relation, radius luminosity relation
radon, Rn
radon (atomic number 86)
RAID array
RAID array of hard disk
Raman effect
Raman scattering
Raman spectroscopy
Raman spectrum
Ramsden eyepiece
range finder
Rankine-Hugoniot relation
rapid burst
rapid oscillation
rare earth
R association, R-association
ratio
ray
lunar ray
Rayleigh
Rayleigh criterion, Rayleigh limit
Rayleigh number
Rayleigh scattering
Rayleigh-Taylor instability
Razin effect
rubidium, Rb
rubidium (atomic number 37)
Ritchey-Chretien telescope, RC
R Canis Majoris star, R CMa star
R Coronae Borealis star, R Cor Bor star, RCB star
R Canis Majoris star, R CMa star
R Coronae Borealis star, R Cor Bor star, RCB star
R Coronae Borealis star, R Cor Bor star, RCB star
rhenium, Re
rhenium (atomic number 75)
read out noise, RON
read-out noise
real anomaly
receiver
recombination
recombination line
recurrent nova
red giant bump, red bump
red giant clump, red clump
reddened star
reddening
reddening law
red dwarf
red dwarf star
red dwarf flare star
red giant
red giant star
giant branch, RGB, red giant branch
red giant bump, red bump
red giant clump, red clump
red giant tip
rgb photometry, red-green-blue photometry
redshift, red shift
redshift distance relation
redshift-distance relation
redshift magnitude relation
redshift-magnitude relation
red star
red supergiant
red supergiant star
reduction method
reference frame
reference system
Reference systems
reflecting telescope, reflector
reflection
reflection grating
reflection nebula
Reflection nebulae
reflecting telescope, reflector
reflector antenna, reflector antennas
reflector antenna, reflector antennas
refracting telescope
refraction
refraction angle, angle of refraction
angle of refraction
refractive index
regression of node
sunspot number, Wolf number, relative sunspot number
relativistic astrophysics
relativistic cosmology
relativistic disk
relativistic discs UK
relativistic effect
relativistic electron
relativistic fluid dynamics
relativistic plasma, relativistic gas
relativistic mechanics
relativistic particle
relativistic plasma, relativistic gas
relativistic star
relativistic velocity
relaxation time
remote control system
remote sensing
research
reseaux
residual intensity
resolution
resonance gap
resonance line
retardation
reticle
reticon array
dark adaption, retinal adaption
photosphere, reversing layer
rutherfordium, Rf
rutherfordium (atomic number 104)
roentgenium, Rg
roentgenium (atomic number 111)
giant branch, RGB, red giant branch
rgb photometry, red-green-blue photometry
RGB tip distance
distance obtained from the tip of the red giant branch
rgu photometry
rhodium, Rh
rhodium (atomic number 45)
rhenium, Re
rhenium (atomic number 75)
rho Cassiopeiae star, rho Cas star
rho Cassiopeiae star, rho Cas star
rhodium, Rh
rhodium (atomic number 45)
Right Ascension, celestial longitude
rigid body rotation
rill
ring
ring division
ring galaxy
ring nebula
Ritchey-Chretien telescope, RC
R magnitude
radon, Rn
radon (atomic number 86)
automated telescope, robotic telescope
Roche limit
Roche lobe
rocket-borne instrument, rocket borne instrument
roentgenium, Rg
roentgenium (atomic number 111)
read out noise, RON
read-out noise
Rosseland opacity
rotating body
rotating shell
rotating star
rotation
rotational velocity
r-process, r process
RRab star
RRa star
RRb star
RRc star
RR Lyrae star, cluster type variable star
RR Telescopii star
RS Canum Venaticorum star
R star
ruthenium, Ru
ruthenium (atomic number 44)
rubidium, Rb
rubidium (atomic number 37)
runaway star
ruthenium, Ru
ruthenium (atomic number 44)
rutherfordium, Rf
rutherfordium (atomic number 104)
RV Tauri star
RW Aurigae star
sulfur, S, sulphur
sulfur (atomic number 16)
lenticular galaxy, S0 galaxy
Saha equation
samarium, Sm
samarium (atomic number 62)
sampling
Saros cycle
satellite
satellite-borne instrument, satellite borne instrument
satellite laser ranging
Saturn
antimony, Sb
antimony (atomic number 51)
SBF distance, SBF
surface brightness fluctuation distance
SBF distance, SBF
surface brightness fluctuation distance
scandium, Sc
scandium (atomic number 21)
scale height
scandium, Sc
scandium (atomic number 21)
Schmidt camera
Schmidt telescope
Chandrasekhar-Schoenberg limit, Chandrasekhar-Schonberg limit, Schoenberg-Chandrasekhar limit, Schonberg-Chandrasekhar limit
Chandrasekhar-Schoenberg limit; the mass-limit for an isothermal stellar core
Chandrasekhar-Schoenberg limit, Chandrasekhar-Schonberg limit, Schoenberg-Chandrasekhar limit, Schonberg-Chandrasekhar limit
Chandrasekhar-Schoenberg limit; the mass-limit for an isothermal stellar core
Schwarzschild metric
Schwarzschild radius
scientific field
scientific and related field
scintillation
scintillation counter
South Celestial Pole, SCP, S.C.P.
S Doradus star, P Cygni star
Sloan photometry, SDSS photometry
selenium, Se
selenium (atomic number 34)
seaborgium, Sg
seaborgium (atomic number 106)
search for extraterrestrial life, SETI
season
seasonal phenomena
secondary cosmic ray
secondary mirror
secondary star
secular parallax
seeing
seeing monitor
segmented optics
seismology
selection effect
selective absorption
selenium, Se
selenium (atomic number 34)
selenology
self-absorption, self absorption
self-calibration method, self calibration method
semi-barium star, semibarium star
semiconductor device
semi-detached binary star, semidetached binary star
semimajor axis, semi-major axis
semiminor axis, semi-minor axis
semi-regular variable star, semiregular variable star
sensitivity
sensitometer
South Ecliptic Pole, SEP, S.E.P.
separation
S star, Se star
search for extraterrestrial life, SETI
sextant
Seyfert galaxy
Seyfert nucleus
seaborgium, Sg
seaborgium (atomic number 106)
S galaxy
spiral galaxy (Yerkes classification scheme)
South Galactic Pole, SGP, S.G.P.
shadow band
shaped reflector
shell
shell burning
shell star
shepherd satellite
shock
shock wave
Shock waves
short period variable star
shot noise
shutter
silicon, Si
silicon (atomic number 14)
sidelobe, lobe [telescope beam]
sidereal time, S.T.
siderostat
sigma8, sigma_8
the normalization factor of the cosmological matter power spectrum
signal analysis
signal detection
signal processing
signal-to-noise ratio, SNR, signal to noise ratio
signal to noise ratio
silicon, Si
silicon (atomic number 14)
silicon burning
silicon monoxide, SiO
SiO molecule
silicon star
silver, Ag
silver (atomic number 47)
silver coating
simulation
singularity
silicon monoxide, SiO
SiO molecule
SiO maser
site protection
sky
sky brightness
sky noise
atmospheric radiation, sky radiation
sky survey
spectrograph slit, slit
slit mask
Sloan photometry, SDSS photometry
slow nova, novoid
samarium, Sm
samarium (atomic number 62)
Small Magellanic Cloud, SMC
SPH simulation, SPH, smoothed-particle hydrodynamics
tin, Sn
tin (atomic number 50)
supernova, SN
Supernovae: general, SN
supernova remnant, SNR
signal-to-noise ratio, SNR, signal to noise ratio
signal to noise ratio
ISM: supernova remnants, SNR
sodium, Na
sodium (atomic number 11)
soft gamma-ray repeater
solar
solar activity
solar atmosphere
solar constant
solar corona
solar cycle
solar day
solar eclipse
solar filament
solar interior
solar motion
solar nebula
Solar neighbourhood
solar neutrino problem
solar observatory
solar optical telescope
solar oscillation, five minute oscillation
solar parallax
solar physics
solar-planetary relation, solar planetary relation
solar radio telescope
helioseismology, solar seismology
solar storm
solar surface
Solar system: formation
Solar system: general
solar telescope, tower telescope
solar-terrestrial relation, solar terrestiral relation
solar-terrestrial relation, solar terrestiral relation
Solar-terrestrial relations
solstice
acoustic wave, sound, sound wave
sound speed, speed of sound
speed of sound
acoustic wave, sound, sound wave
source
astronomical source
Sources as a function of wavelength
South Celestial Pole, SCP, S.C.P.
South Ecliptic Pole, SEP, S.E.P.
southern hemisphere
South Galactic Pole, SGP, S.G.P.
space
space astrometry
space astronomy
space biology
space debris, debris
space exploration
space geodesy
space law
space motion
space observatory, orbiting observatory
space pollution
space probe, probe
space probe instrument
space research, space science
space research, space science
space telescope
space-time curvature
curvature of space-time
space-time singularity
space vehicle
Space vehicles
Space vehicles: instruments
special theory of relativity
density, specific gravity
intensity, specific intensity
speckle
speckle interferometry
spectroscopic analysis, spectral analysis
spectral band
spectral classification
spectral index
spectral line, spectrum line
line broadening, spectral line broadening
line formation, spectral line formation
line shift, spectral line shift
Zeeman splitting, line splitting, spectral line splitting
line width, spectral line width
spectral resolution
spectral type
spectrograph
spectrograph slit, slit
spectrography, spectrophotography
spectroheliograph
spectroscopy, spectrometry
spectrography, spectrophotography
spectrophotometer
spectrophotometry
spectroscopic analysis, spectral analysis
spectroscopic binary star, spectrum binary star
spectroscopy, spectrometry
spectrum
two-spectrum binary star, spectrum binary star, two spectrum binary star
spectroscopic binary star, spectrum binary star
spectral line, spectrum line
spectrum variable star
velocity of light, speed of light
sound speed, speed of sound
speed of sound
SPH simulation, SPH, smoothed-particle hydrodynamics
spherical aberration
albedo, spherical albedo
spherical coordinate, angular coordinate
SPH simulation, SPH, smoothed-particle hydrodynamics
spicule
spiral arm, arm
spiral galaxy
s-process, s process
strontium, Sr
strontium (atomic number 38)
U Geminorum star, SS Cygni star
S star, Se star
sidereal time, S.T.
stability
standard candle
standard epoch
standard star
star
star association
star atlas
starburst galaxy
star cluster, cluster of star
star count
star distribution
star formation, formation of star
Stark broadening
Stars
Stars: abundances
Stars: activity
Stars: AGB and post-AGB, AGB, post-AGB
Stars: atmospheres
Binaries: close
Binaries: eclipsing
Binaries: general
Binaries: spectroscopic
Binaries: symbiotic
Binaries: visual
Blue stragglers
Stars: carbon
Stars: chemically peculiar
Stars: chromospheres
Circumstellar matter
Stars: coronae
Stars: distances
Stars: dwarf novae, star.variable.UGem-class
Stars: early-type
Stars: emission-line, Be
Stars: evolution
Stars: flare
Stars: formation
Stars: fundamental parameters
Stars: general
Hertzsprung-Russell and C-M diagrams, Color-Magnitude diagrams, H-R and C-M diagrams, H-R and CM diagrams, HR and C-M diagrams, HR and CM diagrams, Hertzsprung-Russel and Color-Magnitude diagrams, Hertzsprung-Russel diagrams
Stars: horizontal-branch, HB
Stars: imaging
Stars: interiors
Stars: kinematics
Stars: late-type
Stars: low-mass, brown dwarfs
Stars: luminosity function, mass function
Stars: magnetic fields
Stars: mass-loss
Stars: neutron, NS
Novae, cataclysmic variables, CV
Stars: oscillations
Stars: peculiar
Planetary systems
Planetary systems: formation
Planetary systems: protoplanetary disks, proplyd
Stars: Population II
starspot
Starspots
Stars: pre-main sequence, PMS
Pulsars: general
Stars: rotation
Starspots
Stars: statistics
Subdwarfs
Supergiants
Supernovae: general, SN
Cepheids
Delta Sct
Stars: variables: general
Stars: variables: RR Lyr
White dwarfs, WD
Stars: winds, outflows
Stars: Wolf-Rayet, WR
Stars: dwarf novae, star.variable.UGem-class
statistical parallax
statistical relation
statistics
steady-state theory, steady state theory
stellar
abundance, chemical abundance, element abundance, stellar abundance
stellar atmosphere
stellar black hole
circumstellar shell, stellar envelope
circumstellar matter, circumstellar cloud, stellar envelope
circumstellar envelope, stellar envelope
stellar evolution
optical interferometer, stellar interferometer
optical interferometry, light interferometry, stellar interferometry
stellar interior
stellar motion
stellar object
star-like object, including star, brown dwarf, and evolved stellar core (NS, BH, WD)
stellar oscillation
stellar population
stellar ring
asteroseismology, stellar seismology
stellar structure
stellar wind
stimulated emission
stimulated radiation
stokes parameter
stratopause
stratosphere
streak photography
streamer
cosmic string, string
stroboscope
Stromgren photometry, Stromgren uvby system, four-color photometry, uvby system
Stromgren sphere
Stromgren photometry, Stromgren uvby system, four-color photometry, uvby system
strong gravitational lensing
strong gravitational lensing (resolved)
strong interaction
strontium, Sr
strontium (atomic number 38)
strontium star
structure
galaxy structure, content of galaxy, structure of galaxy
structure of galaxy
subdwarf
subdwarf star
Subdwarfs
subgiant
subgiant star
subluminous star
Submillimeter
submillimeter astronomy
submillimeter radiation, submillimeter wave
submillimeter radiation, submillimeter wave
subreflector
sulfur, S, sulphur
sulfur (atomic number 16)
sulfur, S, sulphur
sulfur (atomic number 16)
summer solstice
Sun: abundances
Sun: activity
Sun: atmosphere
Sun: chromosphere
Sun: corona
Sun: coronal mass ejections, CMEs
Sun: evolution
Sun: faculae, plages
Sun: filaments
Sun: flares
Sun: fundamental parameters
Sun: general
Sun: granulation
Kreutz sungrazer, sungrazer
Sun: helioseismology
Sun: infrared
Sun: interior
sunlight
Sun: magnetic fields
Sun: oscillations
Sun: particle emission
Sun: photosphere
Sun: prominences
Sun: radio radiation
Sun: rotation
Solar-terrestrial relations
Solar wind
sunspot, sun spot
sunspot cycle
sunspot group
sunspot number, Wolf number, relative sunspot number
Sunspots
Sunspots
Sun: transition region
Sun: UV radiation
Sun: X-rays, gamma rays
Sunyaev-Zeldovich effect, Sunyaev Zeldovich effect
supercluster
superconducting tunnel junction
super-conducting tunnel junction detector
supergalactic coordinate system
supergalactic latitude
supergalactic longitude
supergiant
supergiant star
Supergiants
supergranulation
superhump
apparent superluminal motion, superluminal motion
supermassive star
supernova, SN
Supernovae: general, SN
supernova envelope
supernova remnant, SNR
support system
surface brightness
surface of celestial body, surface celestial body
surface [celestial body]
surface gravity, acceleration of gravity
surface of celestial body, surface celestial body
surface [celestial body]
surface photometry, area photometry
surface property
survey
Surveys
SU Ursae Majoris star
S Vulpeculae star
Swan band
SX Arietis star, helium variable star
SX Phoenicis star
symbiotic nova
symbiotic star
symbol
synchronous detector
synchronous rotation
synchrotron radiation
synodic period
aperture synthesis, synthetic aperture
system
syzygy
tantalum, Ta
tantalum (atomic number 73)
tail
tangential velocity
tantalum, Ta
tantalum (atomic number 73)
t array
T association, T-association
taxonomy
terbium, Tb
terbium (atomic number 65)
technetium, Tc
technetium (atomic number 43)
T dwarf
tellurium, Te
tellurium (atomic number 52)
teaching in astronomy, education
technetium, Tc
technetium (atomic number 43)
technetium line
technetium star
Techniques: high angular resolution
Techniques: image processing
Techniques: interferometric
Techniques: miscellaneous
Techniques: photometric
Techniques: polarimetric
Techniques: radar astronomy
Techniques: radial velocities
Techniques: spectroscopic
tektite
telescope
telescope array
telescope construction
telescope design
dome, telescope dome
telescope instrument, telescope instrumentation
telescope instrument, telescope instrumentation
telescope mirror
telescope mounting
Telescopes
television, TV
television camera, TV camera
television detector, TV camera, television camera tube
television detector, TV camera, television camera tube
telluric line
tellurium, Te
tellurium (atomic number 52)
temperature
temperature control
temperature distribution
temperature effect, thermal effect
temperature fluctuation
temperature scale
temperature zone
terbium, Tb
terbium (atomic number 65)
terminator line
Earth atmosphere, terrestrial atmosphere
geophysics, terrestrial physics
inner planet, terrestrial planet
terrestrial radiation
tertiary mirror
tertiary star
testing
thorium, Th
thorium (atomic number 90)
thallium, Tl
thallium (atomic number 81)
theoretical astrophysics
theory
black body radiation, thermal black body radiation
thermal conductivity
temperature effect, thermal effect
thermal emission
thermal equilibrium
thermal history
thermal instability
thermal property
thermal radiation
thermal stability
thermal structure
thermionic emission, dark current
thermodynamic equilibrium
thermodynamics
thermoluminescence
thermonuclear reaction
thermosphere
thickness
thin film
Thomson scattering
thorium, Th
thorium (atomic number 90)
three-body problem, three body problem
Johnson photometry, Johnson-Morgan filter system, UBV photometry, UBVRI photometry, UBVRIJKL photometry, three-color photometry
three-dimensional spectroscopy, three dimensional spectroscopy
three-dimensional spectrum, three dimensional spectrum
thulium, Tm
thulium (atomic number 69)
titanium, Ti
titanium (atomic number 22)
tidal disruption
tidal distortion
tidal friction
tidal interaction
tidal radius
tide
time measurement, time determination
time measurement, time determination
time-resolved spectroscopy
time signal
time standard
time synchronization, time synchronisation UK
time synchronization, time synchronisation UK
timing equipment, timing device
timing equipment, timing device
tin, Sn
tin (atomic number 50)
titanium oxide, TiO
TiO molecule
tip-tilt mirror, tip tilt mirror
titanium, Ti
titanium (atomic number 22)
titanium oxide, TiO
TiO molecule
Bodes law, Titius-Bode law
Bode's law
thallium, Tl
thallium (atomic number 81)
thulium, Tm
thulium (atomic number 69)
trans-Neptunian object, TNO
topography
torus
total eclipse
integrated magnitude, total magnitude
solar telescope, tower telescope
trace element
tracking
trajectory
transfer function
transit
transit circle
transit instrument
transition probability
transition region
transit telescope
transit time
transmission
transmission grating
trans-Neptunian object, TNO
transparency
transplutonian planet
transport process
transverse velocity
trigonometric parallax
triple star
tritium
tritium, an isotope of hydrogen
Trojan group
tropical year
Tropic of Cancer
Tropic of Capricorn
tropopause
troposphere
true anomaly
true position
T subdwarf
T Tauri star, TTS, YY Orionis star
T Tauri star, TTS, YY Orionis star
Tully-Fisher relation
tungsten, W
tungsten (atomic number 74)
turbidity
Turbulence
turbulence Earth atmosphere
turbulence [Earth atmosphere]
turbulence star atmosphere
turbulence [star atmosphere]
turnoff point
television, TV
television detector, TV camera, television camera tube
television camera, TV camera
twilight
atmospheric scintillation, twinkling
two-body problem, two body problem
two-color diagram, two color diagram
two-color photometry, two color photometry
two-dimensional detector, two dimensional detector
two-dimensional spectroscopy, two dimensional spectroscopy
two-dimensional spectrum, two dimensional spectrum
Cassegrain antenna, Cassegrain antennas, two reflector antennas, two-reflector antennas
two-spectrum binary star, spectrum binary star, two spectrum binary star
Type Ia supernova
Type Ib supernova
Type Ic supernova
Type II supernova
uranium, U
uranium (atomic number 92)
Geneva photometry, ubvgri photometry
Johnson photometry, Johnson-Morgan filter system, UBV photometry, UBVRI photometry, UBVRIJKL photometry, three-color photometry
Johnson photometry, Johnson-Morgan filter system, UBV photometry, UBVRI photometry, UBVRIJKL photometry, three-color photometry
Johnson photometry, Johnson-Morgan filter system, UBV photometry, UBVRI photometry, UBVRIJKL photometry, three-color photometry
Cape photometry, UCBV photometry
U Geminorum star, SS Cygni star
ultraviolet, UV
ultraviolet astronomy, UV astronomy
ultraviolet background
ultraviolet camera
ultraviolet color
ultraviolet continuum
ultraviolet detector
ultraviolet excess star, UV excess star
ultraviolet extinction
ultraviolet filter
Ultraviolet: galaxies
Ultraviolet: general
Ultraviolet: ISM
ultraviolet radiation, ultraviolet_light
ultraviolet line
ultraviolet luminosity
ultraviolet source, ultraviolet object
ultraviolet observatory
ultraviolet photography
ultraviolet photometry
ultraviolet radiation, ultraviolet_light
Ultraviolet: solar system
ultraviolet source, ultraviolet object
ultraviolet spectrograph
Ultraviolet: stars
ultraviolet survey
ultraviolet telescope
U magnitude
umbra
underabundance
unit
Universal Time, U.T., UT
universe, cosmos
unsharp masking
intrinsic variable star, unstable star
upper atmosphere
upsilon Sagittarii star
uranium, U
uranium (atomic number 92)
Uranus
urca process
Universal Time, U.T., UT
UT1
coordinated Universal Time, UTC
UU Herculis star
ultraviolet, UV
ultraviolet astronomy, UV astronomy
Stromgren photometry, Stromgren uvby system, four-color photometry, uvby system
UV Ceti star
ultraviolet excess star, UV excess star
UV Persei star
UX Ursae Majoris star
UX Ursae Majoris-like star
vanadium, V
vanadium (atomic number 23)
vacuum
vacuum technique
vanadium, V
vanadium (atomic number 23)
van Allen radiation belt
van Allen belt
vapor deposition
variability
variable source
variable star
Walraven photometry, VBLUW photometry
velocity
velocity curve
velocity dispersion
velocity distribution
velocity ellipsoid
velocity field
velocity of light, speed of light
velocity space
ventilation
Venus
vernal equinox
vertical circle
Very Large Array, VLA
very large telescope
very long baseline interferometer, VLBI
very long baseline interferometry, VLBI
vibration
vibrational spectrum
vignetting
Vilnius photometry
virial theorem
virtual observatory
viscosity
visibility function
visible radiation, light
visible spectrum
vision
visual acuity
visual binary star
visual magnitude
visual observation
Very Large Array, VLA
V magnitude
Voigt profile
volatile
volcano
von Zeipel theorem
pixel, picture element, voxel
VPH grating
VY Sculpturis star
tungsten, W
tungsten (atomic number 74)
Walraven photometry, VBLUW photometry
water
water ice, ice
water maser
water vapor
wave
waveform analysis
waveguide
wavelength
wave motion
wave propagation
Waves
WCN star
WC star
White dwarfs, WD
weak G band star
weak gravitational lensing
weak gravitational lensing (resolved)
weak interaction
weak-line T Tauri star, WTTS
weather station
webcam
white dwarf
white dwarf star
White dwarfs, WD
white hole
wide-angle lens, wide angle lens
broad band photometry, wide-band photometry
broad-band photometry
wide binary star
wide-field telescope, wide field telescope
Wilson-Bappu effect, Wilson Bappu effect
Wilson effect
window
wind vane
winter solstice
WN star
Wolf diagram
sunspot number, Wolf number, relative sunspot number
Wolf-Rayet star
Stars: Wolf-Rayet, WR
WR star
weak-line T Tauri star, WTTS
W Ursae Majoris star
W Virginis star
WZ Sagittae star
xenon, Xe
xenon (atomic number 54)
xenon, Xe
xenon (atomic number 54)
X-ray radiation, X-ray
X-ray absorption
X-ray astronomy
X-ray background
X-ray binary star
X-ray bright point
X-ray burst
X-ray continuum
X-ray detector
X-ray diffraction
X-ray emission
X-ray flare
X-ray fluorescence
X-ray identification
X-ray line
X-ray luminosity
X-ray map
X-ray nova
X-ray observatory
X-ray polarization
X-ray pulsar
X-ray quasar
X-ray radiation, X-ray
X-rays: binaries
X-rays: bursts
X-ray scattering
X-rays: diffuse background
X-rays: galaxies
X-rays: galaxies: clusters
X-rays: general
X-rays: ISM
X-ray source
X-ray spectrograph, X-ray spectrometer
X-ray spectrograph, X-ray spectrometer
X-ray spectroscopy
X-ray spectrum
X-rays: stars
X-ray star
X-ray structure
X-ray survey
X-ray telescope
X-ray transient
yttrium, Y
yttrium (atomic number 39)
Yagi antenna
y array
y-array
ytterbium, Yb
ytterbium (atomic number 70)
year
Yerkes classification
Yerkes galaxy classification scheme
yoke mounting
young disk Cepheid
young disc Cepheid UK
young star
young star cluster
ytterbium, Yb
ytterbium (atomic number 70)
yttrium, Y
yttrium (atomic number 39)
T Tauri star, TTS, YY Orionis star
zero-age main sequence, ZAMS
Z Andromedae star
Z Camelopardalis star
Zeeman splitting, line splitting, spectral line splitting
zenith
zenith distance
zenith hourly rate
zenith telescope
zenith tube, photographic zenith tube
zero-age horizontal branch
zero-age main sequence, ZAMS
zero point
Mira variable star, Miras, omicron Ceti star, zeta Aurigae star
zinc, Zn
zinc (atomic number 30)
zirconium, Zr
zirconium (atomic number 40)
zirconium star
zinc, Zn
zinc (atomic number 30)
zodiac
zodiacal dust
zodiacal dust cloud
zodiacal light
zone of totality
zirconium, Zr
zirconium (atomic number 40)
ZZ Ceti star
