The sky on December 13, 1979 — as it really was
That day the Sun stood in Ophiuchus, while the horoscope says "Sagittarius". The gap is 23.6° of precession.
Bodies on the ecliptic (noon UTC)
- ☉︎ Sun — 260.9° · sign Sagittarius · constellation Ophiuchus
- ☽︎ Moon — 191.7° · sign Libra · constellation Virgo
- ☿︎ Mercury — 241.2° · sign Sagittarius · constellation Libra
- ♀︎ Venus — 288.5° · sign Capricorn · constellation Sagittarius
- ♂︎ Mars — 159.3° · sign Virgo · constellation Leo
- ♃︎ Jupiter — 160.0° · sign Virgo · constellation Leo
- ♄︎ Saturn — 176.5° · sign Virgo · constellation Virgo
- ☽︎ Moon 32% 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]
last quarter, 32% lit; the Moon was 401,542 km away.
astronomy-engine - How far Earth has travelled since [EXACT]
46.8 orbits of the Sun — 43,991 million km, that is 57,220 return trips to the Moon; 17,097 rotations of Earth; with the Sun — 339.8 billion km around the Galactic centre, 13.1 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 169 million km away; today it is 245 million km (farther by 1.5×).
astronomy-engine; checked against JPL Horizons for 2026-09-14 - Solar cycle [ESTIMATE]
That day fell in solar cycle 21, on the rise to maximum (36% through the cycle).
SILSO smoothed minima - When the sky repeats [EXACT]
Mars returns to that day’s point of its orbit on December 21, 2026; Jupiter — in 2026; a full moon exactly on this date — December 13, 2046
sidereal periods: Mars 686.98 d, Jupiter 11.862 yr - How far the sky has drifted since [EXACT]
The vernal point has shifted 2,340″ 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.