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 .

Between the Clouds

Photo of the Week.. The evening sky peeks through as we fly between layers of clouds.

Astronomy news for the week starting Friday, July 11, 2003.

The Moon this week achieves its full phase, when it is opposite the Sun in the sky, at around noon on Saturday the 13th, when it is not visible in North America. The night of Friday the 12th, the Moon will therefore rise a bit before sunset, the night of Saturday the 13th a bit after, and since the difference is split, both risings could be called "full moon."

As the Moon travels its orbit around the Earth, it will pass five degrees to the south of Neptune the night of Monday the 14th, then the same angle to the south of Uranus during the day of Wednesday the 16th, the dim outer planets respectively in Capricornus and southwestern Aquarius. These are but a prelude to the passage of the waning gibbous Moon past Mars the night of Wednesday the 16th, actually the morning of Thursday the 17th, when the planet is just barely (from mid-latitudes) to the north of the lunar disk. From southern climes, including southern Florida, the Moon actually passes over, or occults, the planet, a rare sight indeed. And one made more special -- even the near misses are special -- as a result of Mars's unusual brightness, the result of its growing proximity to Earth. Watch for the red planet to rise in the southeast around 11 PM, the time getting ever earlier. The other naked-eye planets are effectively gone from the sky, as they are too near the Sun -- in angle, not in distance -- to be easily viewed. But with the Moon clearing out of the way, the ever-present stars are there for us to admire.

Because the Earth orbits the Sun close to one degree per day (no coincidence, as the degrees in a circle were meant to fit the number of days in a year), the sky -- as viewed at the same time each night -- slips to the west one degree per day (per night) as well. Thus are the seasonal constellations. Now we see Scorpius passing by us far to the south (for northerners) late in the evening, and the famed Big Dipper already to the west of near-overhead. Directly beneath the curve of the Scorpion's tail lies the constellation Ara, the Altar, while directly north of it are the southern stars of Ophiuchus, the Serpent Bearer. The modern boundaries of Ophiuchus actually extend across the ecliptic, making it the "thirteenth" constellation of the Zodiac, the Sun passing against it from November 30 to December 17, a period longer than the duration of the Sun against the classical zodiacal constellation of Scorpius, where the Sun lingers for a mere five days. Nevertheless, Ophiuchus is not considered a part of zodiac, just a kind of interloper.
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