International standards and resources

The International Astronomical Union (IAU) provides comprehensive information on naming, abbreviations and capitalisation for celestial bodies.

Australian conventions and resources

The Astronomical Society of Australia follows the IAU usage for naming, capitals and so on. The Geoscience Australia website is also useful.

Use initial capitals for the names of planets and their satellites (‘moons’), constellations, asteroids, specific meteor showers, comets, stars, and other unique celestial bodies:

Saturn     Triton [a satellite]     Orion     C/1995 O1 (Hale-Bopp)     the Milky Way     the Solar System     Polaris     the Southern Cross     878 Mildred [an asteroid]     the Arietids [a meteor shower]     the Horsehead Nebula

Use initial capitals for Earth, Moon and Sun when used in an astronomical context or publication. When referred to more generally, use lower case. When referring to Earth, do not use an article (the):

Earth has one satellite – the Moon.

Mercury is the planet closest to the Sun, followed by Venus and Earth.

The sun rises every morning; sometimes, the moon is visible.

Seeds were planted in the earth.

When these proper nouns are used adjectivally, use lower case:

solar storm     lunar eclipse

Use initial capitals for the names of space programs:

Project Apollo

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