The sky on December 21, 1931 — as it really was
That day the Sun stood in Sagittarius — sign and constellation agree here.
Bodies on the ecliptic (noon UTC)
- ☉︎ Sun — 268.7° · sign Sagittarius · constellation Sagittarius
- ☽︎ Moon — 48.2° · sign Taurus · constellation Aries
- ☿︎ Mercury — 268.4° · sign Sagittarius · constellation Sagittarius
- ♀︎ Venus — 294.6° · sign Capricorn · constellation Sagittarius
- ♂︎ Mars — 278.7° · sign Capricorn · constellation Sagittarius
- ♃︎ Jupiter — 142.4° · sign Leo · constellation Leo
- ♄︎ Saturn — 292.6° · sign Capricorn · constellation Sagittarius
- ☽︎ Moon 88% 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 gibbous, 88% lit; the Moon was 399,352 km away.
astronomy-engine - How far Earth has travelled since [EXACT]
94.8 orbits of the Sun — 89,080 million km, that is 115,869 return trips to the Moon; 34,621 rotations of Earth; with the Sun — 688 billion km around the Galactic centre, 26.6 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 356 million km away; today it is 245 million km (closer by 1.5×).
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 November 23, 2027; Jupiter — in 2026; a full moon exactly on this date — December 20, 2029
sidereal periods: Mars 686.98 d, Jupiter 11.862 yr - How far the sky has drifted since [EXACT]
The vernal point has shifted 4,752″ 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.