This is the Dudley Observatory Skywatch Line for Wednesday, April 18th, and Thursday, April 19th, written by Louis Suarato.
The 12% illuminated, waxing crescent Moon sets at 10:38 Wednesday night. After sunset, the Moon forms a triangle with the Pleiades star cluster and Venus. Look about 12 degrees north of the Moon for the Pleiades, and 8 degrees below the Pleiades for Venus. All planets, with exception of Venus, rotate clockwise. Venus rotates counter-clockwise, and unlike other planets, the Sun rises in the west and sets in the east. Venus rotates at a relatively slow speed of 4 miles per hour, or once every 243 Earth days. Venus orbits the Sun once every 224.7 Earth days, making a Venusian day longer than its year. If you were on the surface of Venus, you would experience a sunrise and sunset only once every 1.08 years. Uranus is different than other planets in that it rotates on its side. That means that for 42 years Uranus’ south pole face the Sun, and for 42 years, Uranus north pole faces the Sun. This unique rotation provides each pole with 42 years of continuous sunlight or darkness. Thursday night, the Moon will be 2 degrees below Taurus’ brightest star, Aldebaran.
Jupiter rises at 9:26 p.m. in Libra. Almost simultaneously, Jupiter’s largest moon, Ganymede, is occulted by the planet. Ganymede’s occultation ends at 10:39 p.m. as the moon reappears from behind the pole of the gas giant. Saturn rises at 1:15 a.m. in Sagittarius, followed by Mars 42 minutes later. Before dawn, the two planets are high in the south-southeast. Mars, slightly brighter than Saturn, is on the left. The red and ringed planets are separated by about 10 degrees. Saturn becomes stationary on Wednesday, and begins its retrograde, or westward motion. Saturn is also at aphelion, its furthest distance from the Sun since 1959.
The Albany Area Amateur Astronomers invite you to join them Thursday evening at miSci, beginning at 7:30 p.m., for their monthly meeting. The guest speaker is Dr. E. Bruce Watson, professor of Earth and Environmental Sciences at RPI. Dr. Watson specializes in the geochemistry of deep Earth in the lower crust and upper mantle. His topic will be “Ancient Crystals in the Early Earth”. Dr. Watson is a graduate of the University of New Hampshire and earned his Ph.D. from MIT. Dr. Watson has over 300 publications to his name.