June Podcast: A Month of Moonwatching

This episode is sponsored by Celestron, manufacturer of high-quality telescopes and an industry leader in developing exciting optical products with revolutionary technologies.

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Listen to an illustrated version of this podcast on Sky & Telescope’s YouTube channel.

Stargazers, as a rule, crave darkness. Nothing gets our juices flowing like a wide-open canopy of stars set like diamonds on black velvet. But for those of us in the Northern Hemisphere, June offers the shortest nights of the year. Even so, let’s make the most out of the dark hours that we’ve got!

Let’s follow the Moon all around the sky. It takes the Moon 29½ days to complete a cycle of phases, from new to full and back to new. And throughout that lunation, as it’s called, that giant ball of rock and dust is constantly gliding around Earth in its orbit. Sure, each day the Moon rises in the east and sets in the west, just like the Sun does, but that’s because Earth is spinning. But on any given night the Moon’s orbital motion causes it to shift eastward in the sky with respect to the stars around it.

We’ve got a great opportunity to watch this subtle movement on June 1st. For those of you in eastern North America, early that evening you’ll see that fat lunar crescent about 1½° to the right of Regulus well up in the southwestern sky. But keep watching! The Moon appears to move eastward in its orbit by almost exactly one diameter per hour — a convenient coincidence! So over time the Moon sneaks closer and closer to Regulus, and they’ll be just ½° apart at moonset. For those of you out west, the Moon and Regulus are closest together right as twilight ends, and then you can watch the two of them move apart.

Check out June’s Sky Tour podcast to find out what other celestial objects will be visited by the Moon this month. For example, if you miss the Moon gliding past Regulus on June 1st, it’ll slide past Mars likewise on the evening of 29th. And look about three fists to their lower right — you might catch a glimpse of Mercury lurking in the twilight glow just about the western horizon.

Next, note where the Sun sets, and then make a quarter turn to the left, to face south. There you’ll find Spica. It’s the alpha star in the constellation Virgo, who’s lying down in the sky, with her head off to the right and her legs toward left. Before it gets too late, look about 1½ fists to the lower right of Spica for a quartet of fainter stars arranged like a misshapen box. This is Corvus, the Crow. And below that, hovering just above the horizon, is the very long and very dim constellation Hydra, the Water Snake.

There’s another constellation in the evening skies of June that’s well-known but tricky to find. It’s Libra, which represents a the set of scales. But it wasn’t always regarded as such. Ancient Babylonians considered the stars of Libra to be part of another constellation that’s nearby. And which one might that be? You’ll have to listen to Sky Tour to find out!

Of course, this month’s Sky Tour podcast is chock full of entertaining celestial tidbits like this. It’s a fun and entertaining way to figure out — in just 13 minutes — “what’s up” in the starry sky. So why not give it a try? Grab this month’s episode, go out on a clear June evening, and get a guided tour of this month’s celestial highlights!

Read the full podcast transcript.