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