5 Sky Events of the Week: Stellar Peak-a-Boo and Leo Paws at the Moon

This view of Jupiter from the Hubble Space Telescope shows the distinctive cloud structures on this gas giant. This week sky-watchers can see Jupiter riding high in the southern evening sky. Credit: NASA, ESA, Michael Wong (Space Telescope Science Institute, Baltimore, MD), H. B. Hammel (Space Science Institute, Boulder, CO), and the Jupiter Impact Team

With a change of seasons only days away, mid-March skies offer celestial sights that even the novice stargazer will find easy to enjoy.

Lunar rectangle. After nightfall on Monday, March 10, look for the waxing gibbous moon to form a corner of a rectangle with Jupiter and the Gemini twins, Castor and Pollux, high in the southern sky.

To the naked eye, the moon will make a particularly pleasing pairing with the superbright Jupiter. The two will be separated by only 5 degrees, equal approximately to the width of your fist held at arm’s length.

Lunar occultation. On the same night, the waxing gibbous moon will appear to go in front of a faint (but visible with the naked eye) star, when seen from North America.

Starting at 11:45 p.m. EDT, the 3.6-magnitude star Alkibash, in the constellation Gemini, will appear to glide behind the unlit portion of the moon and reappear about an hour later.

To see this occultation event, it is best to use binoculars, especially when it comes to viewing the most exciting moment when the star appears to wink out and disappear behind the dark portion of the moon.

Located about 95 light-years from Earth, the faint star is actually a double star. But its much fainter companion is visible only through a small telescope.

The faint star Lambda Geminiroum or Alibash will be occulted by the moon late night on March 10 as seen from North America. Credit: SkySafari
The faint star Lambda Geminorum, or Alkibash, will be occulted by the moon late at night on March 10, when seen from North America. Credit: SkySafari

Lion’s heart. On Thursday, March 13, look for the moon to have moved eastward in the evening sky, parking just south of of the regal blue-white star Regulus.

Marking the heart of the constellation Leo, the Lion, Regulus (78 light-years from Earth) will appear to the lower left of the moon, only 5 degrees away.

As an added challenge, look carefully with binoculars (so as to cut the glare from the moon) and see if you can track down the very faint naked-eye star Subra, to the left of the moon. This 130-light-year-distant star marks the front paw of the king of beasts.

In case you miss the celestial action, by the next night, Friday, March 14, the moon will have jumped to the other side of Regulus.

Mercury down under. Early-bird sky-watchers in the Southern Hemisphere have their best chance this year to see Mercury in the morning.

Face due east about an hour before local sunrise. Brilliant Venus will guide you to Mercury sitting to its lower right about 20 degrees away, equal to about the width of two stacked fists held at arm’s length.

Southern Hemisphere sky-watchers will get to see Mercury have its best morning apparition in the east just before local dawn this week. Credit: SkySafari
Southern Hemisphere sky-watchers will get to see Mercury have its best morning apparition in the east just before local dawn this week. Brilliant Venus will act as a convenient guidepost for tracking down the innermost planet of the solar system. Credit: SkySafari

Full moon. On Sunday, March 16, at 1:08 p.m. EDT (17:08 UT), the full moon makes its appearance. With spring only days away in the Northern Hemisphere, the March full moon is also known as the Crow Moon or Sap Moon for the running of syrup from the maple trees this time of the year in northeastern parts of North America.

By nighttime, you can find the silvery orb within the borders of the constellation Virgo, the Maiden, a traditional springtime stellar pattern.

Scan the sky about 20 degrees west of the moon, and you will find the bright orange beacon of Mars and the lead star of Virgo, Spica.

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Changing Planet

Andrew Fazekas, aka The Night Sky Guy, is a science writer, broadcaster, and lecturer who loves to share his passion for the wonders of the universe through all media. He is a regular contributor to National Geographic News and is the national cosmic correspondent for Canada’s Weather Network TV channel, space columnist for CBC Radio network, and a consultant for the Canadian Space Agency. As a member of the Royal Astronomical Society of Canada, Andrew has been observing the heavens from Montreal for over a quarter century and has never met a clear night sky he didn’t like.