Starstruck

This Week's Night Sky: See an Eclipse of Two Jupiter Moons

In the middle of the week, the Lyrid meteor shower creates a late-night show.

View Images

Jupiter, the largest planet in the solar system, plays host to an eclipse of its moon Europa by another of its moons, the volcanic Io, pictured here in a simulated view.


Earth’s moon poses with picturesque worlds this week, as it cozies up to Venus and multicolored stars.  And mid-week, a cosmic harp, the Lyrid meteors, will generate fiery notes across the sky.  

A cosmic quadrilateral. About an hour after sunset on Monday, April 20, the thin sliver of the crescent moon hangs in the western sky and marks the corner of a giant quadrilateral that also includes white Venus, orange Aldebaran, and the Pleiades. With the glare of twilight, the last will be difficult to see, so try using binoculars to hunt down the 300-light-year-distant open star cluster.

View Images

At dusk on Monday, the moon anchors a celestial quadrilateral with Venus, Aldebaran, and the Pleiades star cluster.


Io eclipses Europa. Later that night, binocular and telescope users get a chance to observe Jupiter's moon Io cast a shadow onto Europa from 11:44 to 11:47 p.m. EDT. During these few minutes, the ice-encrusted Europa will fade by a factor of five, making this a very quick but cool cosmic event to witness.

Luna visits the goddess of love.  Look for the waxing crescent moon in the sky at dusk on Tuesday, April 21, and you’ll notice it has joined the “evening star,” also known as the planet Venus. Staring at the cosmic duo is the red giant Aldebaran, the eye of Taurus the bull.

View Images

On Tuesday, the moon joins Venus within the constellation Taurus, the bull.


Lyrids meteors. Stay up late on Wednesday, April 22, and look for a flurry of shooting stars streaming from the northeast sky near the constellation Lyra. The Lyrid meteor shower should peak starting after 11 p.m. local time but promises to really kick in after midnight when the moon will have set and left behind dark skies.  

View Images

Sky-watchers looking up late Wednesday into Thursday morning can watch the Lyrid meteor shower peak in the northeast sky.


Until the pre-dawn hours on Thursday morning, as many as 15 to 20 meteors per hour should be visible across the Northern Hemisphere in areas away from light-polluted cities.

Mercury pairs with Mars. At dusk on Thursday, April 23, use brilliant Venus as a guide to a close encounter between Mercury and Mars near the western horizon. Mercury appears just above a much fainter Mars, separated by only 1.5 degrees, which is about equal to the width of three lunar disks.

View Images

Mercury and Mars offer an observing challenge just after sunset on Thursday.


Luna visits the King of Worlds. Both Jupiter and the waxing gibbous moon dominate the southwest sky after nightfall on Sunday, April 26. The super-bright celestial objects make a striking pair separated by only 5 degrees, which is equal to the width of your three middle fingers held at arm’s length.  

View Images

On Sunday, the bright gas giant Jupiter forms a pretty pair with the moon throughout the night.


This proximity is just an optical illusion, of course, since sunlight reflected off the surface of the moon takes only 1.33 seconds to reach Earth and light bouncing off the cloud tops of Jupiter make the trip to our planet in 42.8 minutes.

Happy hunting!

Follow Andrew Fazekas, the Night Sky Guy, on Twitter, Facebook, and his website.

Comment on This Story