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 .

Saturn in Gemini

Photo of the Week.. In March of 2004, Saturn (the bright body to the right) was seen beautifully placed in southern Gemini. Castor and Pollux lie to the left.

Astronomy news for the week starting Friday, April 2, 2004.

This is the week of the full Moon, the phase reached on Monday, April 5, close to the time of moonset (and sunrise) in North America. In homage to spring, which is now well upon us, the April full Moon is poetically called the "Grass Moon," and sometimes the "Egg Moon" or "Planter's Moon." Two days later, on Wednesday the 7th, the Moon goes through perigee , where in its monthly rounds it is closest to the Earth. Since the Sun is just past the vernal equinox in Pisces, this full Moon is also just past the autumnal equinox in Virgo, and just south of the celestial equator. The remainder of the week sees our companion in its waning gibbous phase as it rises over an hour later each night.

Venus still dominates the western evening sky. Though now past its greatest eastern elongation with the Sun, the planet is still setting progressively later each night, not dropping below the horizon until 10:30 PM (Standard Time, 11:30 Daylight Time), well after the end of twilight. Getting closer to Venus, Mars sets only half an hour later, the red planet passing north of Aldebaran (and the Hyades of Taurus) the night of Tuesday the 6th. Compare the similar colors of the two. Mars is red because the iron oxides in its surface "soil" efficiently reflect the red component of sunlight, while Aldebaran is reddish because -- for a star -- it is relatively cool. To the east of these two nearby planets shine Saturn, high in the early evening in Gemini, and Jupiter. In southern Leo, Jupiter is transiting the meridian to the south about 10 PM (Standard Time), before Venus and Mars set, giving us a grand show of all four bright planets in the western sky at the same time.

Early Sunday morning, April 4, most clocks in the US and Canada advance an hour to "Daylight Time." "Standard Times" are the local times at "standard meridians" spaced 15 degrees apart beginning at Greenwich. Eastern Standard Time is local time at 75 degrees west longitude, Central Standard at 90 degrees, and so on. For Daylight Time, we just pretend we are in the next time zone to the east, Central Daylight Time being the same as Eastern Standard Time, again and so on. The effect is that the Sun seems to rise an hour earlier and set an hour later than it otherwise would.
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