Solar system showing relative size of (but not distance between) planets.

Keep tabs on our planets with Morrison Planetarium's quarterly guide to planetary activity.


The planet Mercury, image by NASA/JPL

The littlest planet starts the season hidden in the Sun's predawn glow, in the midst of passing behind our star as we see it in the sky. Reaching superior conjunction on April 18, it continues moving east of the Sun, emerging into the evening twilight late in the month. It's 22 degrees east of the Sun on May 16 (greatest eastern elongation). At this time, the high angle of the ecliptic (the plane of the solar system) with respect to the horizon causes it to set almost two hours after the Sun. Then, as Mercury swings around back to Earth's side of the Sun, its close pass near Venus (less than half a degree) on the 28th might be visible in the twilight with optical aid, very low in the west-northwest an hour after sunset. Mercury is washed from view after the end of May as it passes between Earth and the Sun, reaching inferior conjunction on June 10. In late-June, it re-emerges in the predawn sky, rising shortly before the Sun.

Mercury's encounter with the Moon on April 10-11 is too close to the Sun and not visible in the glow, but their pass on May 13 is visible low in the west after sunset. However, their next meeting on June 10 is again too close to the Sun to be observed.



The planet venus, image by NASA/Caltech/JPL

Having passed behind the Sun in late March, Venus is hidden from view by the Sun's glow for all of April, eventually appearing in the twilight after sunset in early May and slowly rising higher each evening.

Although the Moon's pass near Venus on April 11-12 is not visible, the following encounters between the two occur increasingly farther out of the Sun's glow and are gradually easier to see (although binoculars may help, since they're both within the first day or two after new Moon, and the Moon is an extremely-thin waxing crescent). Look for them on the evenings of May 12, and June 11, both times very low on the horizon just after sunset.



The planet Mars, image by NASA

The Red Planet is an evening object all season, though gradually moving lower in the west after sunset. In early April, look for it high in the west at nightfall, located inside the large Winter Hexagon asterism, through which it passes by the end of May, crossing the line between the bright stars Pollux and Procyon on the Hexagon's eastern side.

The waxing crescent Moon sweeps past Mars on the evenings of April 16, May 15, and June 13.



The planet Jupiter, by NASA

The largest of the planets is a predawn object all season, rising before the Sun and located in the southeast an hour before dawn. Through the season, it moves only nine degrees eastward against the stars, confined to the constellation Aquarius the Water-Carrier the whole time. Remember how close Jupiter and Saturn were (one-tenth of a degree) back in December? Their angular separation is slowly increasing from 12 degrees on April 1 to 15 degrees on May 1 and to 18 degrees on June 1.

The Moon can be seen passing nearby on the mornings of April 7, May 4-5, and June 1, and June 28.



The planet Saturn, by NASA/JPL/Saturn institute

Like its larger, jovian sibling (see Jupiter), the famed Ringed Planet is a morning sight through the season, located degrees from Jupiter at the beginning of April. Gradually, the slow-moving giant is being left behind in Capricornus the Sea-Goat as brighter Jupiter creeps farther to the east into Aquarius. It plods two degrees eastward from April 1 through May 23, then goes retrograde May 23, reversing its motion and backing up a degree by the end of June...winding up only one degree from where it started in April. This backward motion (retrograde motion) is explained in Highlights.

Look for the waning Moon near Saturn on the mornings of April 6, May 3 and 31, and June 27.


Sunrise & sunset table

Times are PDT for San Francisco, California, and will vary slightly for other locations.

April 1
Sunrise | Solar Noon | Sunset
6:54 am | 1:13 pm | 7:33 pm 

May 1 
Sunrise | Solar Noon | Sunset
6:13 am | 1:06 pm | 8 pm

June 1 
Sunrise | Solar Noon | Sunset
5:48 am | 1:07 pm | 8:26 pm


Cosmic lectures

The Benjamin Dean lecture series brings the world's leading experts in astronomy, astrophysics, and more to the Academy's Morrison Planetarium. Stay tuned—lectures are coming back in a virtual format this June!