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Ecliptic Zodiac Simulator

Day of year

The Sun travels along the ecliptic, passing through 12 zodiac constellations each year. Contrary to astrology, it does not spend equal time in each sign.

Earth orbiting the Sun

SunAriTauGemCanLeoVirLibScoSagCapAquPisEarth

Viewed from Hong Kong — ecliptic tilted 23.5° to celestial equator

Before you start

The Sun appears to pass through twelve constellations each year — the zodiac. This is the astronomical basis behind astrology.

Key idea

As Earth orbits the Sun, we see the Sun projected against different background constellations. The path is called the ecliptic.

What you see

  • Top-down Earth–Sun orbit
  • Zodiac constellation labels around the orbit
  • Current zodiac sign for the selected day

Try this

  1. Set day to March 21 — Sun near the vernal equinox in Pisces/Aries
  2. Advance three months and watch Earth move a quarter orbit
  3. Note the Sun does not spend equal time in each sign

Common mistakes

  • Believing the zodiac has exactly 12 equal segments astronomically
  • Ignoring Ophiuchus, through which the ecliptic also passes

Glossary

Ecliptic
The Sun's apparent yearly path on the celestial sphere.
Zodiac
Constellations along the ecliptic.

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