The Sky This Week 2004 April 16 – 23
The Moon returns to the evening sky this week. New Moon occurs on the 19th at 9:21 am Eastern Daylight Time. Luna climbs past three naked-eye planets during the course of the week, providing some spectacular sights in the late twilight hours. Look for the Moon near Venus on the evenings of the 22nd and 23rd. On the latter night she stands just two degrees north of ruddy Mars. On the 24th she closes in on the golden glimmer of Saturn.
This is the time of year when we bid farewell to the winter constellations. The bright stars of the Great Winter Circle are now fading in the twilight, and mighty Orion seems to settle wearily into the western horizon as twilight fades to darkness. The dazzling star Sirius follows the Hunter by an hour or so, and as the star nears the horizon it seems to twinkle through all the colors of the rainbow. I often receive reports, especially from folks living in areas with large sky vistas, of the spectacular show that the Dog Star puts on when it sets. It was probably this phenomenon that caused the ancient Greeks to describe its color as ìredî, and to give it its name, which translates into ìThe Scorching Oneî. Winters bright stars are replaced by the more subdued lights of spring, which in turn will give way in a few short months to the bright stars of the summer sky.
Venus continues to dazzle us with her searing white glow. She is approaching her greatest brilliancy for the year, and is now about as far north of the ecliptic as she can get. She is easily visible before sunset, and keen-eyed skywatchers can spot her during daylight hours.
Mars is now just another background star as Venus draws nearer each night. The red planet has faded to near-obscurity, appearing half as bright as nearby Aldebaran. The Moon pays him a visit on the evening of the 23rd, and he and Venus continue to leave Aldebaran behind them as the Bull slowly drifts toward the horizon. Mars is drawing a bead on Saturn, and next month he’ll overtake his distant ringed rival.
Saturn is also courted by the Moon this week. The ringed planet still enjoys a few hours in the dark sky after twilight, but he’s gradually falling toward the Sun’s advance. If you have a telescope, take advantage of the next few weeks to get your last good looks at him for the year.
Rounding out the evening’s planet feast is Jupiter, who crosses the meridian at around 10:00 pm. For most of the evening he and Venus will dominate the sky, and it is interesting to compare their differences in color and light. Jupiter is also the best target for the small telescope for late-night skywatchers. His four bright moons are easily visible in almost any instrument, and modest aperture instruments will reveal his dusky cloud belts, which constantly evolve in form and detail.
