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Photo of the Week. Ocean sunrise, the Sun reflecting off the distant water. See the whole sequence: 2, 3, 4, 5. The oblateness is caused by refraction in the Earth's atmosphere; the lower edge of the Sun is refracted upward more than the upper edge. Irregularities are the result of atmospheric layering.

Astronomy news for the week starting Friday, April 18, 2008.

Starting out as a fat, waxing gibbous, the Moon hits its full phase around the time of Moonset the morning of Sunday, April 20. The night of Saturday the 19th, the not-quite-full Moon will thus rise just before sunset, while the following evening, the just-past-full Moon will rise just after sunset. The rest of the week finds the Moon in the shrinking, waning, gibbous as it heads towards third quarter next week on Monday the 28th. Almost exactly three days after full phase, the Moon then passes apogee, where it is about five percent farther from the Earth than average.

Swinging down through the southern part of the Zodiac, the nearly full Moon will appear to the south of Virgo's Spica the night of Saturday the 19th. After passing through Libra, it then takes on Scorpius, the celestial Scorpion, passing close to Antares during the daytime on Wednesday the 23rd. That morning then finds the Moon to the west of the star, while on the morning of Thursday the 24th, the Moon will appear to the east of the star.

The evening sky is still graced by Mars, with its once-abundant water and the still-open possibility of primitive life, and Saturn, with its striking ring system. Mars, transiting the celestial meridian well before sunset, can now be seen after the end of twilight in the west in central Gemini, where the red planet makes a fine colorful trio with orangy Pollux and white Castor above it. To the east of Mars, Saturn resides two zodiacal constellations over, in Leo, tight up against (and to the east of) Regulus, the planet transiting the meridian high to the south just as twilight finally ends. Mars then sets in the northwest around 2 AM Daylight Time, moments after Jupiter rises in the southeast, with Saturn setting around 4 AM Daylight. The remainder of the morning is spent with Jupiter to the northwest of the classical figure of Sagittarius as it fades into dawn.

Lood for the Lyrid meteors the morning of Tuesday the 22nd, though the bright Moon will blot out most of them.

Though spring is now in full gear, it's hard to let go of the winter constellations. At the end of twilight, Orion is way down the western sky. A look to the north, however, still very nicely reveals pentagon- shaped Auriga with bright Capella. Ranking number six in apparent brightness (in part because it is a close double star), Capella is so far north that it never sets for anyone living above 44 degrees north latitude, which includes the northern tier of US states and almost all of Canada. On the other hand, below 44 degrees south latitude, it cannot be seen at all (much as Alpha Centauri, the sky's closest star, is not visible in most of the US).
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