During the next week Jupiter approaches and passes Saturn for their once-in-a-generation Great Conjunction on December 21, 2020.
On December 15, the razor-thin appears to the lower right of Jupiter and Saturn after sunset. The planets are 0.6° apart.
A little later as the sky darkens further and the moon sets, the planets are visible together low in the southwest.
Just 5 days before the conjunction the crescent moon shines beneath the converging planets. The planet gap is 0.5°, the apparent diameter of the moon in the sky. For the next several evenings, your pinky finger at arms length covers both planets.
December 17, the crescent moon appears to the upper left of the converging planets. The planets are 0.4° apart.
The moon is to the upper left of the planets. The gap between Jupiter and Saturn is 0.3°.
The waxing gibbous moon is to the upper left of the impending conjunction. Bright Jupiter is 0.2° to the lower right of Saturn.
One night before the conjunction, Jupiter is below Saturn.
Jupiter passes Saturn during daylight hours in North America and South America when they share the same celestial longitude – the definition of a conjunction. By nightfall the planets are still close in the southwest after sunset.
Conjunction evening! Jupiter is immediately to the lower left of Saturn.
Through a small telescope or spotting scope, both planets appear in the same field of view. Jupiter’s four largest moons and Saturn’s moons are easy to see.
A binocular may reveal some of the Jovian moons.
The planets are visible as separate “stars” to the unaided eye. They do not merge into a single point or suddenly brighten.
During the next week, watch the Jupiter move away from Saturn.
October 23, 2021: This morning the bright moon is near the Pleiades star cluster. Mercury is making its best morning appearance. In the evening sky, Venus, Jupiter and Saturn are easy to spot.
October 22. 2021: Speedy Mercury is low in the east before sunrise. It is putting on its best morning performance of the year. Arcturus, in the east-northeast, is about the same altitude as Mercury.
October 21-November 1, 2021: Brilliant Venus steps through Ophiuchus to the upper left of the star Antares in the southwest after sunset . Afterward, the planet steps farther eastward.
October 21, 2021: The bright moon is low in the west about an hour before sunrise. Mercury is in the east at about the same altitude as Arcturus. Venus, Saturn, and Jupiter shine from the evening sky.
December 18, 2021: This is the anticipated launch date of the James Webb Space Telescope, the largest and most sophisticated space telescope view the universe.