astr - atom
- astroarchaeology
- astrobiology
- astrochemistry
- astrodynamics
- astrographic cameras
- astrographic catalogs
- astrographs
- astrolabes
- astrology
- astrometric binary stars
- astrometric instruments
- astrometry
- astronomers
- astronomical constants
- astronomical geodesy
- astronomical instruments
- astronomical optics
- astronomical research
- astronomical techniques
- astronomical unit
- astronomy
- astrophotography
- astrophysical jets
- astrophysics
- asymptotic giant branch
- ataxites
- atlases
- atmospheres
- atmospheric density
- atmospheric extinction
- atmospheric radiation
- atmospheric refraction
- atmospheric scattering
- atmospheric scintillation
- atmospheric tides
- atmospheric windows
