Last updateWed, 27 Sep 2017 1pm


29 Sep 2017
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Rise early on these dark mornings, and you will be rewarded by a close planet pair, lots of bright stars, a star popping out from behind the moon, a meteor shower from Halley’s Comet, and a dust cloud in our solar system. Evenings give us Saturn with rings now open to the max, and the Milky Way. Our morning twilight all-sky chart for October 2017 at shows the changes in positions of naked-eye planets and stars of first magnitude or brighter at mid-twilight, when the sun is 9 degrees below the eastern horizon, some 40 minutes before sunrise. A bonus in October, while we’re still on daylight saving time: You don’t need to get up extra early by the clock to enjoy dark morning skies! As the month progresses, stars will appear to drift from east to west along the tracks shown, owing to the revolution of Earth around…
31 Aug 2017
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Our morning twilight all-sky chart for September, viewable below, shows the changes in positions of the naked-eye planets and the stars of first-magnitude or brighter, less than an hour before sunrise. Changes are caused by the motion of the Earth and the other planets in their orbits. Stars will appear to drift from east to west across the sky as weeks pass, thanks to the revolution of Earth around the sun. Venus now dominates the predawn sky, but is getting a little lower each morning, because it is heading toward the far side of the sun, where it will arrive in January 2018. Annually in September and October, the huge Winter Hexagon—in clockwise order from its brightest member, Sirius, Procyon, Pollux and Castor, Capella, Aldebaran and Rigel, with Betelgeuse inside—is well-placed high in the sky before dawn. The flashing blue-white Dog Star Sirius is its most prominent and southernmost member.…
28 Jul 2017
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The summer of 2017 marks the 54th anniversary of my first successful expedition to observe a total solar eclipse. The date was July 20, 1963, when our carload of astronomy graduate students from the University of Michigan made the long drive from Ann Arbor to the path of totality in Quebec. Cumulus clouds parted—and we had a spectacular view. When it came to astronomy, I was hooked. I hope some of you have a chance to make the journey to the August eclipse’s path of totality. This event is part of the Saros series—same as the eclipse I saw in 1963. These eclipses are spaced at intervals of 18 years plus about 11 1/3 days, and after three Saros intervals—called an Exeligmos—a solar eclipse very much like the one in 1963 happens again, within a similar track through our region of the world, only farther south. Instead of Alaska through…