First off, if you’re reading this on Sunday, March 12th, check your clock – Daylight Savings Time started in the US overnight. If you haven’t turned your clocks ahead one hour, better get on that. Astronomically, that doesn’t mean a thing, except that you’ll have to stay up later to catch dark skies in what’s left of those clear winter nights. Sunday is a full moon too, and while that’s pretty in its own right, this week isn’t the greatest for dark-sky viewing.
Luckily, the planets are continuing to shift. Venus is now racing retrograde toward the sun (and becoming a thinner and thinner crescent), and in just about 2 weeks it will pass between us and the Sun and become the “Morning Star”, leaving the evening sky.
As it disappears though, Jupiter is returning to the evening scene, rising now between 9 and 10 pm, and earlier every night. Tuesday evening, Jupiter, the Moon, and Spica (the brightest star in Virgo) will form a nice triangle in the eastern sky.
Jupiter is a great target for even small telescopes – cloud bands are clearly visible, and even a good pair of binoculars can resolve the 4 large Galilean moons – Europa, Io, Ganymede, and Callisto. Give it some practice early in the week, and note the positions and movement of the moons. Back in 1609 and 1610, Galileo noticed that these “stars” moved with Jupiter, and realized that the apparent back-and-forth motion of these bodies, as if on springs tied to Jupiter, was the same oscillation that would be observed if they were in circular orbit, as viewed edge on. This revolutionary idea that something was orbiting another body in the solar system caused Galileo some trouble, and started the scientific movement away from the the Aristotlean geocentric model of the universe.
If your telescope is good enough, watch Jupiter on Wed, 3/15. Starting at about 10:48 pm EDT, Europa’s shadow will cross the disk of Jupiter, followed by the moon itself starting at about 11:55 pm EDT.
Even with a not-so-great telescope (like mine), you can still catch some activity in the Galilean moons. Later in the week, on Friday, you can catch an eclipse of Io – at about 10:24 pm EDT, the moon will pass from the west side into Jupiter’s shadow and fade to black.
I’m looking forward to having Jupiter back in the night sky, it’s always a surprise just how much you can see through even a small telescope!
Get Out There!