521.

The cluster NGC 2232 is well placed The open star cluster NGC 2232 (mag 4.2) in Monoceros culminates at around midnight local time. Wed, 28 Dec 2016 (2,687 days ago) in Monoceros

522.

Mercury at inferior solar conjunction Mercury passes around the near side of the Sun. Wed, 28 Dec 2016 at 13:43 EDT (2,687 days ago) in Sagittarius

523.

Conjunction of the Moon and Saturn The Moon and Saturn share the same right ascension, at a separation of 3°36'. Tue, 27 Dec 2016 at 15:41 EDT (2,688 days ago) in Ophiuchus

524.

Mercury at perihelion Mercury passes its orbit's closest point to the Sun. Sun, 25 Dec 2016 at 09:23 EDT (2,690 days ago) in Sagittarius

525.

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. Sun, 25 Dec 2016 at 00:54 EDT (2,690 days ago) in Libra

526.

Close approach of the Moon and Jupiter The Moon and Jupiter pass close to each other. Thu, 22 Dec 2016 at 13:12 EDT (2,693 days ago) in Virgo

527.

Conjunction of the Moon and Jupiter The Moon and Jupiter share the same right ascension, at a separation of 2°24'. Thu, 22 Dec 2016 at 11:39 EDT (2,693 days ago) in Virgo

528.

Comet 45P/Honda-Mrkos-Pajdusakova passes perihelion Comet 45P/Honda-Mrkos-Pajdusakova makes its closest approach to the Sun. Thu, 22 Dec 2016 (2,693 days ago) in Capricornus

529.

Ursid meteor shower 2016 The Ursid meteor shower reaches its peak. Thu, 22 Dec 2016 (2,693 days ago) in Ursa Minor

530.

December solstice 21 December will be the shortest day of 2016 in the northern hemisphere. Wed, 21 Dec 2016 at 05:41 EDT (2,694 days ago) in Sagittarius

531.

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. Tue, 20 Dec 2016 at 20:56 EDT (2,695 days ago) in Virgo

532.

December Leonis Minorid meteor shower 2016 The December Leonis Minorid meteor shower reaches its peak. Mon, 19 Dec 2016 (2,696 days ago) in Leo Minor

533.

Lunar occultation of Regulus The Moon will pass in front of Regulus (Alpha Leonis), creating a lunar occultation visible from Australia. Sun, 18 Dec 2016 at 13:08 EDT (2,697 days ago) in Leo

534.

The Orion Nebula is well placed The Orion Nebula (M42; mag 4.0) culminates at around midnight local time. Thu, 15 Dec 2016 (2,700 days ago) in Orion

535.

The Running Man cluster is well placed The Running Man cluster NGC 1977 (mag 4.2) in Orion's sword culminates at around midnight local time. Thu, 15 Dec 2016 (2,700 days ago) in Orion

536.

Comae Berenicid meteor shower 2016 The Comae Berenicid meteor shower reaches its peak. Thu, 15 Dec 2016 (2,700 days ago) in Leo

537.

Mercury at highest altitude in evening sky Mercury is bright and well placed in the evening sky. Thu, 15 Dec 2016 (2,700 days ago) in Sagittarius

538.

Mercury at dichotomy Mercury reaches half phase in the evening sky. Wed, 14 Dec 2016 at 11:47 EDT (2,701 days ago) in Sagittarius

539.

Geminid meteor shower 2016 The Geminid meteor shower reaches its peak. Tue, 13 Dec 2016 (2,701 days ago) in Gemini

540.

Full Moon The Moon reaches full phase and is visible for much of the night. Tue, 13 Dec 2016 at 19:05 EDT (2,702 days ago) in Taurus