Tuesday, March 27, 2012

"On a moonless night in a dark place, you can see your shadow in Venusian light"

Venus, Jupiter, crescent moon meeting up this weekend
[...] The last four weeks or so have been a spectacular time for stargazers, or, more precisely, planet-watchers. Venus and Jupiter have had a conjunction, and on March 13 passed so close to each other in the night sky that they could have exchanged business cards. Throw in the moon on Sunday and Monday nights and it’s a must-look situation.

“When you get a configuration like this, people who don’t normally look up above the horizon find that their eyeballs are being hijacked,” said Alan MacRobert, an amateur astronomer and senior editor at Sky & Telescope magazine.

More news is on the horizon: On June 5, Venus will transit the sun, the last such transit until 2117. With a safe solar filter, the tiny black dot of Venus will be visible as it gradually moves across the sun’s face.


What’s unfolding Sunday and Monday nights is a reprise of what happened Feb. 25 and 26, when the crescent moon slipped past Jupiter and Venus. The two planets have a conjunction like this about once every 24 years, said Geoff Chester, spokesman for the U.S. Naval Observatory.

This is what’s known as an evening apparition of Venus (it can be a morning star or an evening star), and it has been particularly sublime because the planet is relatively high in the sky. The second rock from the sun is near its greatest “elongation” — as far as it ever gets from the sun as seen from Earth — and so it’s up in the sky for a long time before it sets.

It’s also preposterously brilliant. Its magnitude is almost at the maximum for Venus — minus 4.4. (The lower the magnitude, the brighter the object.) On a moonless night in a dark place, you can see your shadow in Venusian light, Chester said.

“The circumstances for this evening apparition are about as good as they get,” Chester said. “Then you throw Jupiter into the mix, which is usually the second brightest planet, then you’ve got a couple months when the moon is playing footsie with them. And that’s what makes it particularly interesting.”

Those unfamiliar with such things should be warned that planet-watching is a subtle pleasure, enhanced by the right attitude. Not much actually happens. The planets don’t zoom around. Nothing collides or explodes. There are no cameo appearances by comets. The moon and planets will drop below the horizon by late evening and some people may feel the need to find an after-party. [...]

I have seen them on the few cloudless nights we've had recently. I thought it was dramatic.


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