The Sun’s apparent path among the stars over the year, mirroring the plane of the Earth’s orbit. It is tilted by 23.4° to the celestial equator. The Moon and planets always stay close to it, which helps to recognise them.
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Related terms
- Zodiac
The band of sky along the ecliptic where the Sun, Moon and planets move. The ecliptic actually crosses 13 constellations, including Ophiuchus. Astrology’s “signs” no longer match the constellations, shifted by precession: astrology is not a science.
- Equinox
The moment the Sun crosses the celestial equator, around 20 March and 22 September; day and night then last about 12 hours everywhere. The point the Sun crosses in March, the vernal equinox point, is the zero of right ascension. On that day the Sun rises due east.
- Solstice
The moment the Sun reaches its greatest declination, +23.4° around 21 June and −23.4° around 21 December. In the northern hemisphere June brings the longest day and December the longest night. Around the June solstice in France and the UK, true darkness is short or missing.
- Planet
A body that orbits the Sun and shines by reflecting its light. Mercury, Venus, Mars, Jupiter and Saturn are visible to the naked eye; they move slowly among the stars, near the ecliptic, and twinkle less than stars. Uranus (magnitude 5.7) and Neptune (7.8) need binoculars or a telescope.
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