SKYLIGHTS

Skylights featured on Astronomy Picture of the Day

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Skylights featured six times on Earth Science Picture of the Day:
1 , 2 , 3 , 4 , 5 , 6

Dramatic sunset

Photo of the Week. Some sunsets are quiet, others filled with drama as we wait for the clouds to clear.


Astronomy news for the week starting Friday, June 30, 2006.


Read A Minute with Jim Kaler, a brief interview on the outer bodies of the Solar System that appears on the U of I home page.

Skylights' "Picture of the Week" for February 24 was featured last week on the Earth Science Picture of the Day .

The Moon begins as a fat waxing crescent, and with the passage of first quarter around noon (near Moonrise) on Monday, July 3, continues during the rest of the week as a waxing gibbous. Two days before the quarter, it passes through apogee, where it is farthest from the Earth. While watching fireworks the night of Tuesday the 4th, you might also admire the Moon as it stands just to the east of Spica and just south of a line between the star and Jupiter. As the sky darkens the following night (Wednesday the 5th), the Moon will be in conjunction with (and about 5 degrees south of) the giant planet.

The next day, Thursday the 6th, Jupiter ceases retrograde motion (westerly against the stars) and begins to move back in its normal easterly direction. On the Libra-Virgo border and not setting until 2 AM, Jupiter dominates the western skies, Saturn and then Mars disappearing by 10:30 or so.

The evening of Sunday the 2nd presents us with a lovely stellar- planetary lineup. As twilight dims, start with Mercury close to the western horizon and then continue up and to the left to Saturn (still stuck near Cancer's Beehive), through Mars (which, now near the Cancer-Leo border, is separating nicely from the ringed planet), and ending in Regulus in Leo. The morning of Sunday the 2nd will be pretty nifty too, as you can then see Venus (rising as dawn begins at 3:30 AM) pass four degrees north of Aldebaran in Taurus (note the pronounced color contrast).

Monday the 3rd gives us a terrestrial special, as the Earth passes aphelion, when and where it is farthest from the Sun, 152,095,745 kilometers (94,507,915 miles), 1.7 percent farther than average. Since we in North America are in summer's highest heat, distance clearly has nothing to do with the seasons, which are caused entirely by the 23.4 degree axial tilt relative to the orbital perpendicular.

Two glorious icons of the sky are near their peaks, Ursa Major's Big Dipper in the northern hemisphere, Crux (the Southern Cross) in the southern (which is fully visible only below about 25 degrees south latitude). Following along behind the Dipper is Bootes, the Herdsman, while following behind the Cross are the bright first magnitude stars of Centaurus, Alpha Cen (the closest star system to the Earth) and Hadar (Beta). To the south and east of these, southerners can admire the modern constellation Circinus (the pair of Compasses), which with Norma (the Square, originally the "Level and Square") gives us a fine set of celestial tools.
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