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 .

Sunset and Hull Down

Photo of the Week.. As the Sun sets over the Pacific Ocean, a distant freighter appears "hull down" on the horizon, its lower hull hidden around the curvature of the Earth. The effect is one of the classic "proofs" that the Earth is a sphere. See the whole set of three pictures to watch the Sun set and the ship sail north. Then expand them to see the panoramic view.

Astronomy news for the week starting Friday, April 16, 2004.

The Moon starts the week in its waning crescent phase, and then quickly passes new on Monday the 19th. On that day, it will also pass nearly in front of the Sun to produce a partial solar eclipse, unfortunately one that will be visible only in the South Atlantic, part of Antarctica, and southern Africa. If the Moon is near to crossing the ecliptic (the apparent path of the Sun) at new, it is likely also to be crossing it at the full phase either before or after the solar eclipse to produce an eclipse of the Moon. One will indeed take place on May 5, but again one not visible in North America. The Moon then takes aim on Venus. Watch for a fine configuration between the two the evening of Thursday the 22nd, when the growing crescent will appear immediately down from the brilliant planet. Earthlight on the lunar nighttime side will add to the show.

On Friday the 16th, Venus will pass several degrees to the north of Aldebaran (and the Hyades) in Taurus, while on the same day the other "inferior planet," Mercury, passes its inferior conjunction with the Sun, when it is more or less between us and the Sun and completely invisible. Look up and to the left of Venus to find much dimmer Mars -- also in Taurus -- as the two draw closer and closer together. Proceeding to the east of Mars (but still in the western sky), find slowly moving Saturn in southern Gemini, and then further over Jupiter (exceeded in brightness only by Venus) in southern Leo. Saturn now sets shortly after 1 AM Daylight Time, while Jupiter crosses the meridian to the south a little over an hour and a half after the end of twilight.

The week is highlighted by one of the year's more prominent meteor showers, the Lyrids, which appear to come out of the constellation Lyra and peak the morning of Thursday, the 22nd. The debris of the Comet of 1861, the Lyrids typically produce about a dozen meteors per hour in a dark sky, which we will have with the Moon well out of the way.

The northern hemisphere is now well into "Dipper Season." In early evening, the Big Dipper of Ursa Major, with its prominent seven stars, is crossing the meridian high, nearly overhead. At the same time, the Little Dipper of Ursa Minor is sticking out to the right of Polaris and the North Celestial Pole, around which the sky's stars appear to go as the Earth rotates below. In contrast to its bigger cousin, the entire Little Dipper is hard to see. In the lights of town only Polaris and the two front bowl stars (Kochab and Pherkad) are readily visible, while the others in between all require a fairly dark sky. Wrapped around the Little Dipper to the right in early evening is the stream of stars that make Draco, the Dragon. Then look to the south of the Big Dipper to find the lovely stellar spattering that makes Coma Berenices, one of the sky's fine naked-eye clusters.
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