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Photo of the Week. A flowering tree glorifies the blue sky.

Astronomy news for the week starting Friday, October 10, 2008.

A quiet week. Yet given the turmoil of daily life, there is something to be said for that. And with the full Moon, we can hardly see the stars, making it even quieter. Yet there is always the full Moon itself. While with its brilliant light it can be an annoyance to astronomers, it remains a charming, even poetic, sight.

We start the week with the Moon in its waxing gibbous phase. Passing formal full phase the afternoon of Tuesday, October 14, the full Moon thus rises just after sunset. It then enters the waning gibbous phase, and passes perigee, where it is closest to the Earth, at the end our week. The morning of Friday the 17th, the Moon also passes against the background of the Pleiades star cluster, though, with the lunar disk so bright, you can't see much without a telescope.

So bright as to allow us nearly to read by its light, the full Moon is full of cultural references, so much so that full Moons are named by a number of cultures. Since the evening eastern ecliptic lies flat against the horizon, the delay in full-Moonrise from one night to the next is at a minimum in September. The Moon thus floods the early evening with Moonlight, hence the "Harvest Moon." The one in October -- the Hunter's Moon -- is not all that much different. That the full Moon seems to rise huge is, sadly, but an illusion caused (some say) by our eye referring it to things on the horizon. The sometime-coppery color comes from absorption of Moonlight by the Earth's atmosphere, the same thing that causes red sunrises. This is the best time to see the "Man in the Moon," the pattern caused by huge, ancient, lava-filled impact basins on the lunar surface, the "maria," which always face us, the Moon not rotating with respect to the Earth, the result of tidal slowing and locking.

Though Venus now does not set until the end of evening twilight, it is still a bit elusive (though readily visible if you look early enough). On the other hand, Jupiter, bright in the southwest until late evening, not setting until 11 PM, is obvious. The morning sky, for some time now planetless, is beginning to show promise, as Saturn, rising around 4:30 AM, has become quite visible in central Leo well to the east of Regulus. Moving off now into the northwestern sky are the gang of five that stretch from Bootes (with Arcturus) through Corona Borealis (the Northern Crown), Hercules, Lyra (with Vega), and Cygnus (topped by Deneb). Cygnus lies in the heart of the northern Milky Way, the white band of light spilling southward through Aquila into Sagittarius and beyond.
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