30 July 2023
We have a rare bird, or should I say birds, in the sky this month, two full moons, on Aug. 1 and Aug. 31, with the second full moon considered a Blue Moon by many folks.
There is a little controversy about what a blue moon is and is not, but the modern definition is that it’s the second full moon in any given month. Since the period between two full moons is 29½ days, Blue Moons don’t happen that often, roughly every year and a half. What makes the two full moons special this month is that they’re both considered “supermoons” since they’re both physically closer to Earth than average. That makes them a little bigger and brighter in the heavens, although most experienced amateur astronomers are hesitant to describe them as truly “super” this month. If you want to call it a “supermoon,” though, that’s your business.
(Mike Lynch)
Another huge highlight for August stargazing is the annual Perseid meteor shower. It’s one of the best of the year that gets going the last few days of July. The peak of the Perseids occurs the night of Aug. 12-13. The best time to see meteors is from after midnight to the start of morning twilight. This year’s good news is that the skies will be free of bright moonlight. A thin crescent moon will rise around 3 a.m., but its meager light shouldn’t interfere. In the countryside, you may see over fifty meteors or more an hour, but even if you’re viewing from areas of moderate light pollution, you should see a decent number of meteors or “shooting stars.” I’ll have more on the Perseids next week in Skywatch.
Along with two full moons and the Perseids, Saturn reaches its closest point to the Earth this year on Aug. 27, what astronomers call opposition. Of course, it’s not just Saturn approaching Earth, but Earth and Saturn approaching each other in their respective orbits around the sun. On Aug. 27, Saturn and Earth will only be separated by just under 815 million miles, which, believe it or not, is considered close for Saturn. Another great thing about Saturn reaching opposition is that just like a full moon, it rises at sunset and sets at sunrise, available all night long! Even though Saturn doesn’t reach opposition until the 27th, it’s available most of the night in August, rising no later than an hour after sunset. Saturn is terrific through even a small telescope, with its gorgeous ring system. The rings are more than 150,000 miles in diameter but only about 50 feet thick on average! This coming Wednesday, Aug. 2, the waning full moon will be parked just to the lower right of Saturn.
The summer constellations are in full bloom now. In the low southern sky, you’ll see Scorpius the Scorpion, which really resembles a scorpion. The brightest star of Scorpius is Antares with its ruddy glow, marking the heart of the great beast. On Aug. 23, depending on where you live on Earth, the last quarter half-moon will either make a very close approach to Antares or will actually pass in front of it, a phenomenon known as occultation. Check your Sky Guide app to see what you’ll see where you live.
Next door, just to the east of Scorpius is Sagittarius the Archer, which looks much more like a teapot. Over in the northwestern sky is the Big Dipper, hanging by its handle. The much fainter Little Dipper is just to the right, with Polaris, the North Star, at the end of the handle. In the northeast is a giant “W.” That’s the constellation Cassiopeia the Queen. That W outlines the throne of Queen Cassiopeia, who is eternally tied into it as punishment for offending Hera, the queen of the gods of Mount Olympus.
Nearly overhead is the Summer Triangle, made up of three bright stars: Vega, Altair, and Deneb. All three of these stars are the brightest in their respective constellations Lyra the Harp, Cygnus the Swan, and Aquila the Evil Eagle. The Summer Triangle is a great tool to help you find these constellations and many other celestial portraits.
For you early-morning stargazing fans, you can get a sneak preview of the same constellations we see in the late fall and early winter evenings. Orion the Hunter, Gemini the Twins, Taurus the Bull, and others are all there to help you start your day and remind you that winter is coming.
Don’t take these warm summer nights for granted!
Mike Lynch is an amateur astronomer and retired broadcast meteorologist for WCCO Radio in Minneapolis/St. Paul. He is the author of “Stars: a Month by Month Tour of the Constellations,” published by Adventure Publications and available at bookstores and adventurepublications.net. Mike is available for private star parties. You can contact him at [email protected].
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