The sky on December 21, 1983 — as it really was
That day the Sun stood in Sagittarius — sign and constellation agree here.
Bodies on the ecliptic (noon UTC)
- ☉︎ Sun — 269.0° · sign Sagittarius · constellation Sagittarius
- ☽︎ Moon — 108.0° · sign Cancer · constellation Gemini
- ☿︎ Mercury — 286.6° · sign Capricorn · constellation Sagittarius
- ♀︎ Venus — 227.4° · sign Scorpio · constellation Libra
- ♂︎ Mars — 198.9° · sign Libra · constellation Virgo
- ♃︎ Jupiter — 263.5° · sign Sagittarius · constellation Ophiuchus
- ♄︎ Saturn — 223.0° · sign Scorpio · constellation Libra
- ☽︎ Moon 97% 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]
full moon, 97% lit; the Moon was 365,889 km away.
astronomy-engine - How far Earth has travelled since [EXACT]
42.8 orbits of the Sun — 40,211 million km, that is 52,303 return trips to the Moon; 15,628 rotations of Earth; with the Sun — 310.6 billion km around the Galactic centre, 12 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 257 million km away; today it is 245 million km (closer by 1×).
astronomy-engine; checked against JPL Horizons for 2026-09-14 - Solar cycle [ESTIMATE]
That day fell in solar cycle 21, on the decline (74% through the cycle).
SILSO smoothed minima - When the sky repeats [EXACT]
Mars returns to that day’s point of its orbit on March 26, 2027; Jupiter — in 2030; 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 2,124″ since that day; the real constellations now sit 23.6° away from the astrologers’ “signs”.
precession 50.29″/yr
Other dates
Computed from the date only; nothing about you is stored.