Sky on December 13, 1987: where the Sun, Moon and planets really were

The real sky on December 13, 1987: Sun in Ophiuchus (horoscope says "Sagittarius"), Moon 50% lit, planet positions from ephemerides.

The sky on December 13, 1987 — as it really was

That day the Sun stood in Ophiuchus, while the horoscope says "Sagittarius". The gap is 23.7° of precession.

astronomy-engine ephemerides (VSOP87/ELP), IAU 1930 constellation boundaries. Positions accurate to a fraction of a degree.

Checkable facts with a tag and a source; the classical reading is in the chart.

The Moon that day [EXACT]
last quarter, 50% lit; the Moon was 399,942 km away.
astronomy-engine
How far Earth has travelled since [EXACT]
38.8 orbits of the Sun — 36,473 million km, that is 47,441 return trips to the Moon; 14,175 rotations of Earth; with the Sun — 281.7 billion km around the Galactic centre, 10.9 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 340 million km away; today it is 245 million km (closer by 1.4×).
astronomy-engine; checked against JPL Horizons for 2026-09-14
Solar cycle [ESTIMATE]
That day fell in solar cycle 22, right at the minimum (13% through the cycle).
SILSO smoothed minima
When the sky repeats [EXACT]
Mars returns to that day’s point of its orbit on June 13, 2027; Jupiter — in 2034; 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 1,944″ since that day; the real constellations now sit 23.7° away from the astrologers’ “signs”.
precession 50.29″/yr

Computed from the date only; nothing about you is stored.