Sunspot group 1598 is hiding behind its innocent name. Late yesterday evening (CDT), it cut loose a powerful X1-class flare, the fourth large flare since rotating around the eastern limb of the sun a few days ago. While not directed toward the Earth, should the spot group continue its cannonade of subatomic spew, we’ll soon be in the line of fire. That could mean high speed streams of solar protons and electrons messing with the magnetosphere and kindling auroral displays. I’ll update in the coming days.
Have you noticed that the planet Saturn’s missing from the night sky? That’s because it’s nearly lined up with the sun and lost from view in the solar glare. That’s not a problem for the orbiting Solar and Heliospheric Observatory (SOHO) which can see nearly to the sun’s edge with a special instrument called a coronagraph.
The device uses a metal disk to block the sun’s glare. SOHO observes from outer space with no atmosphere to reflect and scatter light, so it snap photographs of bright objects very near the sun. Saturn will be in conjunction or closest to the sun Thursday morning Oct.25, when it officially transitions from the evening to the morning sky. We’ll catch our first look at its sumptuous rings again at dawn next month. Of course you don’t have to wait for that either, thanks to the Cassini orbiter, now in its 8th year of loop de loops around the planet. Click HERE to see fresh Saturn photos anytime.
If you have a small telescope and want to watch Ganymede’s shadow stride across the planet, tonight’s the night.
Ganymede is the largest moon in the solar system at 3,272 miles in diameter. That’s half again as big as our own moon. Like any object that reflects sunlight, Ganymede casts a shadow, and tonight, beginning at 9:40 p.m. (CDT) you’ll see that shadow take a bite out of Jupiter’s south polar region. Over the next two hours the remarkably black, perfectly circular dot makes its way from one end of the planet to the other until departing the western limb at 11:41 p.m. (CDT). Astronomers call the event a shadow transit.
Ganymede casts the largest shadow of all of Jupiter’s moons, making it easy to see in almost all telescopes. If you could somehow fly a plane or arrange a balloon ride into the shadow and looked up, you’d see the sun eclipsed by the moon. Lucky Jupiterians!