Skylights featured on Astronomy Picture of the Day

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Photo of the Week. Sunrays (courtesy of Bruce Kaler).

Astronomy news for the week starting Friday, July 10, 2009.

Our ever-present Moon wanes through its gibbous phase the early part of the week, then finally passes its third quarter on Wednesday, July 15, about the time of sunrise, allowing us to see the quarter in its near-perfect state. Enjoy the sight. During the couple remaining days of our period, it will then wane as a fat crescent.

The Moon starts out by lying to the northeast of Jupiter the night of Friday the 10th. That same day, it will also pass a few degrees north of Neptune, and then three days later do about the same with Uranus, not that that will present much of a sight. But at least it's nice to know what's happening. Clearly, Jupiter and Neptune are about in the same place, and sure enough, they pass conjunction with each other on Monday the 13th, Neptune just 0.6 degrees to the north of the giant planet.

Venus presents us with a far better conjunction, when on Tuesday the 14th it passes three degrees north of Aldebaran in Taurus and almost looks like a brilliant member of the Hyades star cluster. Strictly an early morning show, Venus now rises around 3 AM, about as early as it will during this orbital round. As if that is not enough, reddish (and much dimmer) Mars provides a neat contrast to the west of Venus between the Hyades and the Pleiades (Seven Sisters) cluster. And then the morning of Friday the 17th, the Moon gets into the act to the west of both planets and the Pleiades, with Venus, Mars, and the crescent all in a row, presenting a sight well worth getting up for. As a silent coda to the whole planetary positioning affair, Mercury passes superior conjunction with the Sun on Monday the 13th, turning from a morning to an evening planet, though it will not be visible in the evening sky for some time yet.

Not to be forgotten, the evening sky presents us with Jupiter and Saturn. Jupiter, moving retrograde (westerly against the stars) through northeastern Capricornus, rises just after 10 PM Daylight time shortly before the ending of formal twilight. As you admire Venus and Mars, you can also see Jupiter transiting the meridian to the south around 3:30 AM. Doubly-distant and slower-moving Saturn, retaining its position in southeastern Leo, sets a bit over an hour after Jupiter rises as it slowly disappears from the western sky.

With the Moon now rising later, if you have or can get to a dark sky, you might look to the east for the Milky Way, which streams through Cygnus and Aquila down through Sagittarius and beyond.
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