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The sky of Tokyo, Calendar, Planets (December, 2017)

The sky of Tokyo

The sky of Tokyo (8:00 p.m. Mid-December)
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Calendar (December)

3Mercury at stationary point
4Full Moon(This year’s largest Full Moon)
10Last Quarter Moon
13Mercury at inferior conjunction
14Geminid Meteor Shower peaks around 16:00(The best time to observe is after midnight on the morning of the 14th. On the order of 40 meteors per hour are expected. Because there is almost no effect from moonlight and the timing of the maximum is not so bad, conditons are relatively good.)
18New Moon
22Saturn at conjunction / Winter solstice (Sun’s ecliptic longitude 270°)
23Mercury at stationary point / Emperor’s Birthday [Tennou-Tanjyobi] (national holiday)
26First Quarter Moon

The days for the peak activities of the meteor showers are based on the predictions of IMO(International Meteor Organization).

Planets

Mercury
At the beginning of the month, Mercury is positioned low in the western sky just after sunset. It reaches inferior conjunction on the 13th, after that it is positioned low in the southeastern sky just before sunrise. At the end of the month, its elevation increases. From December 23 to January 8, 2018, its elevation is over 10 degree at 30 minutes before sunrise as seen from Tokyo. From the 23rd to the 31st, its brightness is 0.4 to -0.2 magnitude.
Venus
Venus is positioned low in the eastern sky before sunrise, but its apparent location is close to the Sun, making observation difficult.
Mars
From the beginning to the middle of the month, Mars is located in the constellation Virgo and moves east. At the end of the month, it moves into the constellation Libra. It can be seen in the southeastern sky before sunrise. Its brightness is 1.7 to 1.5 magnitude.
Jupiter
Located in the constellation Libra, Jupiter can be seen in the southeastern sky before sunrise. Its brightness is -1.7 to -1.8 magnitude.
Saturn
Located in the constellation Sagittarius, Saturn is positioned low in the western sky just after sunset during the beginning and middle of the month, but its apparent location is close to the Sun and it is not suited for observation. Saturn reaches conjunction on the 22nd, after that it is positioned low in the eastern sky before sunrise.

Source: Ephemeris Computation Office, NAOJ

With the “Sky Viewer” you can easily explore the appearance of a typical urban night sky (planets and constellations are visible). The Celestial Phenomena section of the glossary explains the planetary phenomena terms: greatest elongation, opposition, conjunction, stationary, etc.