Jupiter closes in on Saturn as a prelude to the December 21, 2020 Great Conjunction. During the week look for them in the southwest after sunset. Jupiter is the brightest star in the region. Saturn is to the Jovian Giant’s upper left. Jupiter sets around 7:30 p.m. CST, about 3 hours after sunset for other locations.
by Jeffrey L. Hunt
As the Great Conjunction of 2020 approaches, Jupiter and Saturn are visible in the southwest after sunset during early December.
Jupiter reduces the separation between the planets in the sky by about 0.5°, about the apparent diameter of the full moon.
For more about the Great Conjunction, read our feature article. This is the closest Jupiter – Saturn conjunction since 1623.
Here is more about the planets during December 2020.
The planets are slowly moving eastward in Sagittarius, in front of several dim stars.
Jupiter is slowly over taking Saturn.
Jupiter sets around 7:30 p.m. CST, about 3 hours after sunset. Check your local sunset time and look for the pair of planets beginning about 45 minutes after sundown until they are very low in the west, about 2 hours after sunset.
Here are the charts for the week:
December 1, 2020
2020, December 1: One hour after sunset, Jupiter is 19° up in the southwest, 2.1° to the lower right of Saturn. In the starfield, Jupiter is 2.1° to the lower left of 56 Sagittarii (56 Sgr), while Saturn is 3.7° to the upper left of that star. Additionally, Saturn is 4.5° to the lower right of Sigma Capricorni (σ Cap, m = 5.2).
December 2, 2020
2020, December 2: One hour after sunset, Jupiter is 19.0° up in the south-southwest. Dimmer Saturn is 2.0° to the upper left of the Jovian Giant. In the starfield, Jupiter is 2.3° to the lower left of 56 Sagittarii (56 Sgr), and Saturn is 3.8° to the upper left of the star. Additionally, Saturn is 4.4° to the lower right of Sigma Capricorni (σ Cap).
2020, December 3: One hour after sunset, Saturn is 20.0° up in the south-southwest. Dimmer Saturn is 1.9° to the upper left of the Jovian Giant. In the starfield, Jupiter is 2.4° to the lower left of 56 Sagittarii (56 Sgr), and Saturn is 3.9° to the upper left of the star. Additionally, Saturn is 4.3° to the lower right of Sigma Capricorni (σ Cap).
December 4, 2020
2020, December 4: One hour after sunset, Jupiter is 1.8° to the lower right of Saturn. Jupiter is 2.5° to the left of 56 Sagittarii (56 Sgr), while Saturn is 3.9° to the star’s upper left. Saturn is 4.2° to the lower right of Sigma Capricorni (σ Cap).
December 5, 2020
2020, December 5: Jupiter and Saturn are low in the southwest as the sky darkens after sunset. Saturn is 1.7° to the upper left of Jupiter. Among the stars, Jupiter is 2.7° to the left of the star, while Saturn is 4.0° to the upper left of 56 Sagittarii (56 Sgr). Additionally, Saturn is 4.1° to the lower right of Sigma Capricorni (σ Cap).
December 6, 2020
2020, December 6: One hour after sunset, Saturn is nearly 19° in altitude above the southwest horizon, 1.6° to the upper left of Jupiter. Saturn is 4.1° to the upper left of 56 Sagittarii (56 Sgr), while Jupiter is 2.8° to the lower left of the star. Saturn is approaching Sigma Capricorni (σ Cap). This gap is 4.0°.
December 7, 2020
2020, December 7: Jupiter – over 17° up in the southwest – is 3.0° to the left of 56 Sagittarii (56 Sgr). Saturn is 4.2° to the upper left of that star and 3.9° to the lower right of Sigma Capricorni (σ Cap).
May 30-31, 2022: A fragmented comet may put on a display in the southwestern sky around midnight on this evening. Earth may encounter debris from a comet informally known as SW3.
June 30, 2022: The gap between the four morning planets continues to widen. In the evening sky a green star may lie among the stars of Scorpius that is in the south as twilight ends.
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