Thursday, October 06, 2005

Conjunction of Venus and the Moon TONIGHT

This isn't giving any of you much warning, and it may not apply to folks in some parts of the world, but there will be a conjunction of the very young Moon with a very bright Venus tonight a little bit after sunset.

How do you find it? Well, Venus should be easy: it's the incredibly bright "star" in the Western sky that sets a couple of hours after the sun. (And for those of you who don't know, "West" is the direction where the sun sets. "The Sun" is the big hot glowing circle thing in the sky. "The Sky" is the big blue, white, gray, or black thing hanging over your head when you go outside.) The Moon is supposed to be very young, and very close: my magazines say it will be visible in the same "binocular field" as Venus. (Which means if you look at Venus with binoculars, you should see the thin sliver of moon there.) The Moon will be a slim crescent ("like a banana", as my nephew says), its "horns" or "points" aiming away from the sun.

Depending on atmospheric conditions, we may see the faint ashen glow of Earthshine. Earthshine is the light of the sun reflected first off the daylit side of the Earth and then off the "dark" side of the Moon, which at this time is mostly facing the Earth. It is dim and faint and often hard to see. At its best, when there is a high degree of cloud cover on the daylit side of the Earth, it will shine brightly even in the twilight glow, revealing ghostly images of the Moon's features - but only well after the sun has set. No amount of Earthshine would ever allow the young moon to be visible before or during sunset. (Well, maybe if the sun had briefly flashed a massive solar flare, like in Larry Niven's Inconstant Moon, or had gone Nova, or the entire daylit side of the Earth had been simultaneously nuked - but in any of these cases you'd probably be too busy kissing your ass goodbye to worry much about the Moon.)

Bonus #1: Look for possible Aurorae tonight, or any night when you're outside. Look to the north or south (depending on your hemisphere) for any glowing clouds or beams or patches of sky that look odd. Observe closely, and wait a while: if that thing that looks like a beam of light shining up from the horizon has a multi-colored tip, or if glowing clouds suddenly change shape and move around, odds are you're witnessing an aurora. (Both of these things have happened to me.) Use the links on my sidebar (on the right, near the bottom) to go to a map of current aurora activity.

Bonus #2: A few hours after sunset look for a big bright red "star" rising in the East. (See directions above for finding West, then look on the opposite side of the sky.) This is Mars, moving into a period of bigness and brightness in our skies. Enjoy it while you can - it will fade back into relative obscurity after the start of the new year.

UPDATE (10/6/05, 9:35 PM): Clouded out. I did get to see the moon briefly as I was coming home around 7:45 tonight. (I did some shopping after work - bought the new Liz Phair, Fiona Apple, and Sigur Ros CD's at Joe Nardone's Gallery of Sound, and got a gallon of milk, two quarts of Half-and-Half, The New Avengers #10, Captain America #10, and a big black-and-orange tote for Halloween decorations at Wegman's.) Stargazing from a moving car is always tricky, especially when you're driving. The moon briefly appeared between banks of clouds, low in the west and deep orange from the clouds and a lot bigger than I expected - it wasn't as young as I thought it would be. Still, the clouds were thick enough to block the arc-welder light of Venus. Dagnabbit.

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