Undersky

The sky on Wednesday, June 9, 2027

Sun inGemini
Moon inLeo
Moon phaseWaxing Crescent
Illumination28%
Mercury retrogradeNo

The Moon is in Leo, a young crescent growing in the evening sky.

What is the tropical zodiac?

The tropical zodiac measures the signs from the March equinox rather than from the constellations, so it tracks the seasons and not the star field behind them.

Zero degrees of Aries is defined as the point where the Sun crosses the celestial equator going north, in March. The twelve signs are then simply twelve equal thirty degree steps from there. Undersky is a Western tropical app, and every sign, ingress and aspect on these pages is computed that way.

Because Earth's axis wobbles slowly, a cycle of about twenty six thousand years called precession, that starting point has drifted against the constellations by roughly twenty four degrees since the system was written down. This is why the tropical sign and the constellation the Sun is physically in front of no longer match.

Sidereal astrology, used in the Indian tradition, keeps the signs tied to the stars instead and applies a correction called an ayanamsa. Neither system is a mistake; they measure different things, and it only matters that you know which one you are reading. Here it is always tropical.