The sky of Tokyo, Calendar, Planets (December, 2018)
The sky of Tokyo
Calendar (December)
| 2 | Venusat Greatest Brillancy |
| 7 | Mercury at stationary point / New Moon |
| 14 | Geminid Meteor Shower peaks around 21:00. (The best time to observe is after midnight of this night. On the order of 40 meteors per hour are expected. Conditions are very good after the Moon sets before Midnight.) |
| 15 | Greatest Eastern Elongation of Mercury / First Quarter Moon |
| 22 | Winter solstice (Sun’s ecliptic longitude 270°) |
| 23 | Emperor’s Birthday [Tennou-Tanjyobi] (national holiday) / Full Moon |
| 24 | Holiday |
| 29 | Last Quarter Moon |
The days for the peak activities of the meteor showers are based on the predictions of IMO（International Meteor Organization).
Planets
- Mercury
- Mercury reaches its greatest western elongation on December 15. It can be seen low in the southeastern sky before sunrise around the 15th. From the 7th to the 24th, Mercury’s elevation at 30 minutes before sunrise is higher than 10 degrees as seen from Tokyo. Its brightness is 0.4 magnitude to -0.4 magnitude from December 7 to December 24.
- Venus
- Venus shines brightly in the southeastern sky before sunrise. Venus reaches its greatest brilliancy (magnitude -4.7) on Devember 2. Its brightness is -4.7 magnitude to -4.5 magnitude.
- Mars
- At the beginning of December, Mars is located in the constellation Aquarius and moves east (direct motion). In the end of the month, it moves to the constellation Pisces. It shines after sunset in the southern to southwestern sky and it sets before midnight. Its brightness is -0.0 magnitude to 0.4 magnitude.
- Jupiter
- At the beginning of December, Jupiter is located in the constellation Scorpius and moves east (direct motion). In the middle of the month, it moves to the constellation Ophiuchus. It is positioned low in the southeastern sky before sunrise. In the end of the month, its elevation as seen from Tokyo exceeds 10 degrees at 30 minutes before sunrise. Its brightness is -1.7 magnitude to -1.8 magnitude.
- Saturn
- Saturn moves east (direct motion) in the constellation Sagittarius. Its apparent position is close to the Sun, making observations difficult.
Reference: 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.