The Events of one Night

Lets take a look at the events of the night of April 18,2003. On that night, the sun sets at 7:44 PM Local Daylight Time9. Evening twilight ends one hour and thirty-seven minutes later at 9:21 PM. Four minutes later, Mercury sets in a dark sky. This is a rare event for northern hemisphere observers. In Mercury's six apparitions in 2003 (three morning and three evening), this is the only one in which it will climb high enough to set (or rise) in a dark sky. For the next sixty minutes, until 10:25 PM local time, the sky will be dark. At that time, the Moon rises, flooding the sky with its magnitude -11.9 brilliance. The moon is just two days past full and still 89% illuminated. It is also at a very close perigee (closest to Earth) so its disk is swollen to 32' 56" in diameter, about as large as it can ever appear. During this dark sky period, there are two other planets in the sky. Saturn is in the west about 30 degrees above the horizon and almost due west. The planet is well past its outstanding opposition of the previous December, but is still a fine telescopic target at magnitude +0.2, sporting a 17" disk. The planet's rings during this time are open nearly as wide as they can ever appear, tilted open more than 26 degrees. This is an angle great enough to allow you to view the entire ring system as the far end rises up into view behind the planet. As twilight ends, Jupiter stands nearly at its highest for the night, some 68 degrees above the horizon, directly due south. Jupiter is magnitude -2.0 and its disk is 38" across and is accompanied by its fine contingent of moons. During the dark sky period, there are several deep sky objects available for viewing to test out that new scope. Right after twilight ends, the Great Nebula in Orion (M42) is just high enough to permit crisp viewing in the southwest about 25 degrees high. Just above and to the right of Jupiter is the bright open cluster M44. Also called the "Beehive," this cluster is one of the finest open clusters in the sky. Standing about 40 degrees up in the northeast is the galaxy M51.

9 The times are drawn from calculations using both RedShift 4 and Sky & Telescope's 2003 Sky Almanac. RedShift is based on my position in Northern Delaware while Sky & Telescope's are based on a location near Peoria, Illinois that I have then corrected for my location using instructions provided by Sky & Telescope in the almanac.

This famous ninth magnitude spiral galaxy is one of the sky's great showpieces and a fine test of your new telescope's ability to resolve detail. Also visible, climbing in the east is the constellation Leo that has one of the sky's great double stars. Gamma Leonis consists of two components nearly equal in color and brightness. The stars are closely spaced, but should be easy for the 8-inch scope. In the sky then, we have the chance to view in about a three-hour period, three planets, a bright nebula, an open cluster, a showpiece galaxy, a bright double star and finally the Moon to finish the evening. This short shopping list should provide a fine first test for your telescope. Let's get organized then for the evening ahead.

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