This week's sky
Early April is the best time for viewing another favorite saturnian moon, Iapetus. This two-faced moon has one hemisphere as bright as snow and one as dark as charcoal. The bright side faces Earth when Iapetus lies far west of Saturn, and the dark side points toward Earth when the moon appears far east of the planet. The upshot: Iapetus' brightness changes by a factor of five as it orbits Saturn. The moon shines at its brightest when it reaches greatest western elongation April 2. It then glows at magnitude 10.1.
No other planet rises until well past midnight. The first to appear is Jupiter, which leads the pack of three other planets -- Neptune, Venus, and Mars -- congregating in the morning sky. At magnitude -2.1, Jupiter shines far brighter than any other object in the dim region of sky inhabited by Capricornus. It rises by 5 a.m. local daylight time April 1.
Mar
28