Skylights featured on Astronomy Picture of the Day

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Skylights featured three times on Earth Science Picture of the Day: 1 , 2 , 3 , 4 .

Mars and Moon

Photo of the Week.. Mars confronts the nearly-full Moon on September 8, 2003. Compare with the July 2003 waning gibbous conjunction.

Astronomy news for the week starting Friday, October 10, 2003.

We begin the week with the Moon just past its full phase. The entire rest of the week sees our companion waning through gibbous as it approaches its third quarter next Saturday, the 18th. This time of year, following the "Hunter's Moon," the Moon rises only about a half an hour later each night. The reverse happens after the full Moons of spring, when the delay is nearly an hour and a half, and the waning gibbous disappears quickly from the early evening sky, all the result of differing angles of the ecliptic to the horizon at different times of the year.

Four planets are in various stages of visibility. The toughest of them to see is Venus. In spite of its continuing brilliance, it is still just clearing the Sun after its superior conjunction last August, and sets in bright evening twilight. By mid-November it will be obvious in the southwest after sundown. By far the most prominent is faithful Mars, which from our northern vantage point shines brightly in the southern evening sky. Slowly falling behind the Earth in its orbit, the red planet is now moving easterly against the stellar background south of the "Y"-shaped "Water Jar" of Aquarius. An hour after Mars crosses the meridian to the south (around 10 PM daylight time), the most distant of the "ancient planets," Saturn, rises in Gemini. The Moon will be just to the north of it the morning of Friday, the 17th. And then about an hour after Mars sets (3 AM Daylight Time), bright Jupiter rises. Jupiter takes just under 12 years to make a full circuit of the Sun, and therefore on the average takes a year to move through any given constellation of the Zodiac. Last year the king of the planets dominated dim Cancer. Now it meets a fine rival in bright Leo, the planet currently located south of the center of the prominent constellation. Next year, we will find it in Virgo.

As twilight disappears into the western sky, find magnificent Cygnus nearly overhead (as seen from moderate northern locations), topped at its northern end by first magnitude Deneb. To the west lies pretty Lyra with bright Vega, to the east one of the dimmer constellations of the sky, modern Lacerta, the Lizard. Moving farther to the east, rising is the broad sweep of stars that represents Andromeda, the figure clearly announcing the advancement of fall and chilly northern weather. South of Cygnus lies Aquila with Altair, the three stars (Deneb, Vega, and Altair) making the Summer Triangle. Between Cygnus and Aquila find two small but nicely prominent constellations, Delphinus (the Dolphin), which looks something like a hand with a pointing finger, and Sagitta (the Arrow), which looks for all the world like what it is named after, the little figure sometimes thought of as an arrow shot by Hercules, the great Hero lying to the west of Lyra.
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