National Astronomical Observatory of Japan



The sky of Tokyo, Calendar, Planets (June, 2018)

The sky of Tokyo

The sky of Tokyo (9:00 p.m. Mid-June)
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Calendar (June)

6Mercury at superior conjunction
7Last Quarter Moon
14New Moon
19Neptune at stationary point
20First Quarter Moon
21Summer solstice (Sun’s ecliptic longitude 90°)
27Saturn at opposition
28Full Moon / Mars at stationary point


Mercury reaches superior conjunction on June 6. From the beginning to the middle of the month, its apparent position is close to the Sun and not suited for observation. Its elevation increases at the end of the month. From June 26 to July 13, its elevation as seen from Tokyo exceeds 10 degrees at 30 minutes after sunset. From June 26 to 30, its brightness is -0.3 magnitude to -0.1 magnitude.
Venus shines brightly after sunset in the lower western to northwestern sky. Its brightness is -4.0 magnitude to -4.1 magnitude.
Mars moves east (direct motion) in the constellation Capricornus. It reaches its stationary point on June 28. After passing the stationary point, it moves to the west (retrograde motion). At the stationary point, it seems to stop with respect to the stars. It can be seen before sunrise in the southern to southwestern sky. Its brightness is -1.2 magnitude to -2.1 magnitude.
Jupiter moves west (retrograde motion) in the constellation Libra. It can be seen before sunset in the southeastern to southern sky. Its brightness is -2.5 magnitude to -2.3 magnitude. It still is a good time to observe.
Saturn moves west (retrograde motion) in the constellation Sagittarius. It reaches opposition on June 27 and is suited for observation. Seen from Tokyo, it shines in the lower southeastern sky around 9 p.m. and reaches culmination around midnight. Its brightness is 0.2 magnitude to 0.0 magnitude.

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.