ADVERTISEMENT

ADVERTISEMENT

Astro Bob: Old moon flirts with Venus

A petal-thin crescent moon passes Venus early this week, making a beautiful sight at dawn. We also look back at the recent aurora.

Moon meets Venus
The waning crescent moon glides by Venus on Tuesday morning, July 26, at dawn. The pair will be well-visible low in the northeastern sky about 90 minutes to 45 minutes before sunrise on all three mornings. On Wednesday, July 27, you'll have the opportunity to see a very "old" moon just a day before new.
Contributed / Stellarium
We are part of The Trust Project.
Aurora sextet
This is a sampling of the many forms the aurora displayed on Friday night, July 22, as it romped around the northern sky from dusk until dawn. The color of the intense red plume, center-left, was visible with the eye. The solitary, purple streak, lower-left, is an aurora-related phenomenon called STEVE (Strong Thermal Enhancement Velocity Emission), a river of hot plasma (ionized atoms) streaming at high speed through the upper atmosphere. It appeared briefly at 11:15 p.m. CDT and again at 12:05 a.m.
Contributed / Bob King

I hope you got the chance to see the northern lights the nights of Thursday, July 22, and Friday, July 23. Friday was the better night with lots of activity and color. From dark skies north of Duluth, Minnesota rays splayed across the northeastern sky, even during twilight, as if the show couldn't wait to start.

One of those plumes was so deeply red I could see the color faintly with my eyes — not just in the camera. On occasion, some of the bright pink rays also revealed their subtle hues.

The sun was behind it all, of course. We're a sitting target for its repeated blasts of protons and electrons. Just part of living with a star in your backyard, I suppose. Things look quiet for the next few nights as far as solar storms and auroras go. During the lull you can catch up with the moon and Venus.

Pleiades and moon
A thick lunar crescent rises below the Pleiades star cluster early Saturday morning, July 23.
Contributed / Bob King

On Monday morning, July 25, the moon — three days from new phase — shines in Taurus the Bull, a winter constellation. Not ready for winter quite yet? The stars are always the first to announce its coming. They do it gently like nudging a child awake from a sound sleep.

Winter so soon?

At nightfall, we look up and see the summertime constellations, but as the Earth rotates during the night, those constellations slowly shift westward. By 1-2 a.m. local time, fall star groups like Aquarius, Pegasus and Andromeda increasingly dominate the sky. Just as dawn is getting underway, the early winter stars rise in the east: Taurus, Orion, Auriga and Gemini. On Monday, look about two fists held at arm's length to the lower right of the moon, and you might just spot twinkly, red Betelgeuse — one of Orion's chief luminaries.

ADVERTISEMENT

The next morning, July 26, an even thinner moon will pass 3.5° above brilliant Venus in conjunction. The pairing of a crescent and bright planet stands right at the top of my favorite sky sights. No equipment is needed to observe the conjunction, only a place with an unobstructed view to the east-northeast. Find a comfortable place to sit and soak it in. Starting the day with pretty celestial coupling never fails to buoy my spirits the rest of the day.

On the following morning, July 27, early-risers will have the opportunity to see a very old moon a little more than 24 hours before it passes between the sun and Earth and becomes "new" again. Look very low above the northeastern horizon about an hour before sunrise. To make sure you're there in plenty of time, click here to find out when the sun comes up for your location.

Earthshine
Crescent moon is the best time to see earthshine, light reflected from the Earth that faintly illuminates the lunar surface. Earth and moon phases are complementary — when the moon's a thin crescent, the Earth appears nearly full (and bright!) from the moon. All that light makes the moon's full outline visible.
Contributed / Bob King

On all three mornings, but especially July 25 and 26, the semi-dark outline of the entire moon will be clearly visible, especially if you catch it early before the sky brightens too much. The sun lights the shiny crescent edge, while sunlight reflected from Earth to the moon and back (called earthshine), softly illuminates the rest of the lunar disk.

Happy gazing!

Read more from Astro Bob
Astronomers reveal new details about the eruption that rocked the star in 2019.

"Astro" Bob King is a freelance writer for the Duluth News Tribune.

Related Topics: SCIENCE AND NATURE
"Astro" Bob King is a freelance writer and retired photographer for the Duluth News Tribune. You can reach him at nightsky55@gmail.com.
What to read next
If you're up late watching the Perseid shower this weekend, give a wink to the big hunter. He's baaaak!
Everyone's favorite meteor shower peaks on Friday night, Aug. 12-13.