501.

Comet 141P/Machholz passes perihelion Comet 141P/Machholz makes its closest approach to the Sun. Thu, 17 Dec 2020 (1,291 days ago) in Aquarius

502.

December Leonis Minorid meteor shower 2020 The December Leonis Minorid meteor shower reaches its peak. Sat, 19 Dec 2020 (1,289 days ago) in Leo Minor

503.

Mercury at superior solar conjunction Mercury passes around the far side of the Sun. Sat, 19 Dec 2020 at 22:40 EDT (1,289 days ago) in Sagittarius

504.

December solstice 21 December will be the shortest day of 2020 in the northern hemisphere. Mon, 21 Dec 2020 at 04:55 EDT (1,287 days ago) in Sagittarius

505.

Conjunction of Jupiter and Saturn Jupiter and Saturn share the same right ascension, at a separation of 6'15". Mon, 21 Dec 2020 at 08:34 EDT (1,287 days ago) in Capricornus

506.

Great conjunction of Jupiter and Saturn Jupiter and Saturn will make their closest approach since the year 1623. Mon, 21 Dec 2020 at 13:20 EDT (1,287 days ago) in Capricornus

507.

Moon at First Quarter The Moon reaches first quarter phase – appearing high in the sky at sunset and setting in the west at around midnight. Mon, 21 Dec 2020 at 18:41 EDT (1,287 days ago) in Pisces

508.

Ursid meteor shower 2020 The Ursid meteor shower reaches its peak. Tue, 22 Dec 2020 (1,286 days ago) in Ursa Minor

509.

Conjunction of the Moon and Mars The Moon and Mars share the same right ascension, at a separation of 5°34'. Wed, 23 Dec 2020 at 13:31 EDT (1,285 days ago) in Pisces

510.

Close approach of the Moon and Mars The Moon and Mars pass close to each other. Wed, 23 Dec 2020 at 18:23 EDT (1,285 days ago) in Pisces

511.

The Moon at apogee The Moon recedes to its orbit's furthest point from the Earth, making it appear fractionally smaller than at other times of the month. Thu, 24 Dec 2020 at 11:31 EDT (1,284 days ago) in Pisces

512.

Comet 398P/Boattini passes perihelion Comet 398P/Boattini makes its closest approach to the Sun. Sun, 27 Dec 2020 (1,281 days ago) in Perseus

513.

The cluster NGC 2232 is well placed The open star cluster NGC 2232 (mag 4.2) in Monoceros culminates at around midnight local time. Mon, 28 Dec 2020 (1,280 days ago) in Monoceros

514.

The Moon at aphelion The Moon recedes to its orbit's furthest point from the Sun, which happens each month around the time of full moon. Tue, 29 Dec 2020 at 11:34 EDT (1,279 days ago) in Gemini

515.

The Rosette Nebula is well placed The Rosette Nebula (C49; mag 9.0) in Monoceros culminates at around midnight local time. Tue, 29 Dec 2020 (1,279 days ago) in Monoceros

516.

Full Moon The Moon reaches full phase and is visible for much of the night. Tue, 29 Dec 2020 at 22:28 EDT (1,279 days ago) in Gemini

517.

The cluster Messier 41 is well placed The open star cluster M41 (NGC 2287; mag 4.5) in Canis Major culminates at around midnight local time. Fri, 01 Jan 2021 (1,276 days ago) in Canis Major

518.

The Earth at perihelion The Earth reaches its closest point to the Sun. Sat, 02 Jan 2021 at 08:50 EDT (1,275 days ago) in Pisces

519.

Quadrantid meteor shower 2021 The Quadrantid meteor shower reaches its peak. Sun, 03 Jan 2021 (1,274 days ago) in Bootes

520.

Moon at Last Quarter The Moon reaches last quarter phase – rising in the east at around midnight and appearing high in the sky by sunrise. Wed, 06 Jan 2021 at 04:37 EDT (1,271 days ago) in Virgo