The sky on January 21, 1931 — as it really was
That day the Sun stood in Capricornus, while the horoscope says "Aquarius". The gap is 22.9° of precession.
Bodies on the ecliptic (noon UTC)
- ☉︎ Sun — 300.5° · sign Aquarius · constellation Capricornus
- ☽︎ Moon — 330.5° · sign Pisces · constellation Aquarius
- ☿︎ Mercury — 277.2° · sign Capricorn · constellation Sagittarius
- ♀︎ Venus — 254.2° · sign Sagittarius · constellation Ophiuchus
- ♂︎ Mars — 129.4° · sign Leo · constellation Cancer
- ♃︎ Jupiter — 103.5° · sign Cancer · constellation Gemini
- ♄︎ Saturn — 286.1° · sign Capricorn · constellation Sagittarius
- ☽︎ Moon 7% illuminated
astronomy-engine ephemerides (VSOP87/ELP), IAU 1930 constellation boundaries. Positions accurate to a fraction of a degree.
The day’s dossier, from real data
Checkable facts with a tag and a source; the classical reading is in the chart.
- The Moon that day [EXACT]
waxing crescent, 7% lit; the Moon was 405,351 km away.
astronomy-engine - How far Earth has travelled since [EXACT]
95.7 orbits of the Sun — 89,939 million km, that is 116,987 return trips to the Moon; 34,955 rotations of Earth; with the Sun — 694.6 billion km around the Galactic centre, 26.8 light-days.
29.78 km/s along the orbit; 230 km/s around the Galactic centre - Mars then and now [EXACT]
On that day Mars was 99 million km away; today it is 245 million km (farther by 2.5×).
astronomy-engine; checked against JPL Horizons for 2026-09-14 - When the sky repeats [EXACT]
Mars returns to that day’s point of its orbit on December 24, 2026; Jupiter — in 2038; a full moon exactly on this date — January 21, 2038
sidereal periods: Mars 686.98 d, Jupiter 11.862 yr - How far the sky has drifted since [EXACT]
The vernal point has shifted 4,788″ since that day; the real constellations now sit 22.9° away from the astrologers’ “signs”.
precession 50.29″/yr
Other dates
Computed from the date only; nothing about you is stored.