The sky of Tokyo, Calendar, Planets (July, 2018)
The sky of Tokyo
Calendar (July)
| 6 | Last Quarter Moon |
| 7 | Earth passes aphelion |
| 11 | Jupiter at stationary point |
| 12 | Greatest Eastern Elongation of Mercury |
| 13 | New Moon / Partial Solar Eclipse (not visible from Japan) (Reference: Local Prediction of the Solar Eclipse) |
| 16 | Ocean Day [Umi-no-hi](national holiday) |
| 20 | First Quarter Moon |
| 25 | Mercury at stationary point |
| 27 | Mars at opposition |
| 28 | Full Moon (This year’s smallest Full Moon) / Total Lunar Eclipse (Reference: Local Prediction of Lunar Eclipse) |
| 30 | Aquarid δ (Delta) Meteor Shower peaks around this time. (The best visibility is after midnight for 6~7 days around this date. About 2 meteors per hour are expected. The Moon is very bright, so conditions are bad.) |
| 31 | Mars makes its closest approach to Earth |
The days for the peak activities of the meteor showers are based on the predictions of IMO（International Meteor Organization).
Planets
- Mercury
- In the beginning of July, Mercury can be found in the lower western sky just after sunset. It reaches greatest eastern elongation on July 12. Until July 13, its elevation as seen from Tokyo exceeds 10 degrees at 30 minutes after sunset, making it easy to see. After the middle of the month, Mercury’s apparent location is close to the Sun, making observations difficult. From July 1 to 13, its brightness is 0.0 magnitude to -0.6 magnitude.
- Venus
- Venus shines in the lower western sky after sunset. Its brightness is -4.1 magnitude to -4.2 magnitude.
- Mars
- Mars moves west (retrograde motion) in the constellation Capricornus. It passes opposition on July 27 and makes its closest approach to Earth on July 31, making it easy to see. Seen from Tokyo in the middle of July, it rises in the southeastern sky around 8 p.m. and reaches culmination around midnight. Its brightness is -2.2 magnitude to -2.8 magnitude. Around the period when Mars makes its closest approach to Earth, it shines brighter than Jupiter.
- Jupiter
- Jupiter moves west (retrograde motion) in the constellation Libra. After passing the stationary point on July 11, it moves to the east (direct motion). At the stationary point, it seems to stop with respect to the stars. It can be seen after sunset in the southern to southwestern sky. Its brightness is -2.3 magnitude to -2.1 magnitude. It still is a good time to observe Jupiter.
- Saturn
- Saturn moves west (retrograde motion) in the constellation Sagittarius. It can be seen after sunset in the southeastern to southern sky.Its brightness is 0.0 magnitude to -0.2 magnitude. It still is a good time to observe Saturn.
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.