A weekend of super-conjunctions in the night sky

Almanac Weekly’s Night Sky columnist Bob Berman in his observatory in Willow (photo by Andrea Barrist Stern)

Almanac Weekly’s Night Sky columnist Bob Berman in his observatory in Willow (photo by Philip Kamrass)

It’s one of the coldest winters in memory, and venturing outdoors after sunset probably has the same appeal as playing solitaire in a meat locker. But what’s happening on Friday and Saturday nights is extraordinary. It will be in-your-face easy, dramatic. It shouldn’t be missed.

Hopefully you either saw my little preview at the end of last week’s column, or else are reading this before Friday night, February 20. If it’s clear, simply venture out between 6 and 6:30 p.m. and look in the direction that the sun set. There it is: The skinny crescent Moon closely meets the brilliant planet Venus. Completing the tiny triangle is faint Mars, looking orange. Children are particularly mesmerized by such conjunctions, so if you know any, drag them out too. It’s something they don’t get to experience every day.

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Conjunctions fascinated all civilizations through the centuries. The symbol of Islam is a conjunction between the Moon and a bright star that is almost certainly Venus. This motif appears on more than a dozen flags. And that’s what will appear on Friday evening – but with the lovely bonus of Mars joining the party.

If it’s cloudy on Friday evening, or if you’re reading this too late, another great conjunction unfolds the following night, Saturday. That evening, Venus and Mars are now closest together. The Moon has moved on and is much higher up, above the planetary duo. But now it has its own conjunction, although this one requires that you dig out those binoculars that have been gathering dust in a drawer.

While Venus and Mars closely meet from 6 to 6:30 p.m., the Moon is directly in front of the strange planet Uranus. It’s an occultation, a kind of eclipse. And here’s what’s cool: At seven minutes to 7 p.m., the seventh planet suddenly pops into view. The eclipse is finished, and Uranus – viewed through binoculars – appears as a little green star at the bottom right of the Moon. During the next 15 minutes or so you can watch the Moon’s motion through space as it pulls farther away from the green world.

One more thing:  This month’s crescent Moon is oriented more like a smile than at any other time of year. It’s on its back, not on its side, the way it looks in the fall or summer. It’s a smiley Moon.

There’s even more: Tell the child who’s watching with you, and is now probably hopping up and down with cold, that the glow on the dark side of the Moon is called Earthshine. It’s striking to the unaided eye and powerful through those binoculars. Our own planet – which appears nearly full in the lunar sky right now – is illuminating the nighttime lunar terrain.

It’s also interesting to ponder the distances to these celestial objects. Use the speed of light, which is so fast that if you could travel that quickly, you could go from here to California 60 times in one second. Well, light from the Moon takes 1½ seconds to reach us. At their current distances, each photon of light from Venus requires ten minutes to get here, and 20 minutes from Mars. The light from Uranus has been traveling to us for three hours.

To sum up: The most dramatic event happens this Friday evening between 6 and 6:30 p.m. It’s a dramatic three-way conjunction of Mars, Venus and the crescent Moon. The next night, same time, Mars and Venus are closest, the Moon is now high above them and stands just above green Uranus (through binoculars) starting at 6:53 p.m. And what the heck: If all you’ve got is Sunday evening, you can still see little orange Mars next to dazzling Venus – several chances for clear skies and cool conjunctions.

 

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