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 .

flower and sky

Photo of the Week.. Earthly flower, celestial sky.

Astronomy news for the week starting Friday, August 27, 2004.

This is the week of the full Moon, the phase reached almost at the end of the month, on the night of Sunday, August 29. The concept of the month comes from the moon's 29.5-day phase cycle. In the civil calendar, the month is stretched so as to fit 12 cycles into one year. As a result, individual phases creep forward through the months: the full Moon in September, for example, will take place on the 28th. The rest of the week sees the Moon waning through its gibbous phase, rising ever later after sundown. As it travels through the constellations of the Zodiac, it passes north of Neptune the morning of Saturday the 28th and then north of Uranus the afternoon of Sunday the 29th.

With Jupiter effectively gone from view, the evening sky is devoid of bright planets, which now belong to the morning. Dawn on the morning of Tuesday the 31st presents an excellent sight, with Venus and Saturn in near-conjunction with each other. Both off the eastern edge of classical Gemini, Venus is vastly the brighter, its amazing glow unmistakable. Saturn will be just up and to the left. Watch for a few days before and after the event to see the two approach each other, greet, and then depart, Venus moving rather quickly to the east relative to the much fainter ringed planet. While the two seem close together, their proximity is but an artifact of alignment as seen from Earth . At a distance of 9.7 Astronomical Units from Earth (the AU the average distance between the Earth and the Sun), Saturn is a dozen times farther away than Venus, explaining Saturn's relative faintness. While admiring the conjunction, note the surrounding stars. Up and to the left of the pair lies Pollux in Gemini, while down and to the right is bright Procyon in Canis Minor, the smaller of Orion's two hunting dogs, the Hunter himself now nicely visible as well in early morning skies.

Venus is so bright that it is quite visible in broad daylight. In a clear blue morning sky, look about 45 degrees to the right of the Sun and very high (after hiding the bright Sun behind something), and see if you can find a brilliant white dot. Daylight location can be difficult, as the eyes tend to defocus when looking at a blank sky. When found, daytime Venus is unmistakable. Then you look away and it is lost.

Even without planets, the evening sky still holds stellar delights. We are in the middle of the high progression of constellations that begins with Bootes (marked by orange Arcturus) to the west, and then continues toward the east through Corona Borealis (the Northern Crown), Hercules, Lyra (with brilliant Vega nearly overhead at 9 PM Daylight Time), to Cygnus (the Swan) with Deneb at its tail. With Altair to the south, Vega and Deneb compose the Summer Triangle. Well to the east of Cygnus lie the harbingers of the coming fall, Pegasus and Andromeda, while rising in the northeast are Cassiopeia and Perseus.
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