Author Archives: Alan MacRobert

About Alan MacRobert

Sky & Telescope senior editor Alan MacRobert has been covering all aspects of astronomy since 1982.

This Week's Sky at a Glance logo

This Week’s Sky at a Glance, September 28 – October 6

  Friday, September 28 • Late this evening, spot the little Pleiades cluster to the upper left of the Moon, as shown at right. When we see the Pleiades climb the eastern sky in autumn, their tiny dipper pattern stands on its handle. Saturday, September 29 • There's roughly a two-hour window of darkness now…

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This Week’s Sky at a Glance, August 24 – September 1

  Friday, August 24 • For yet another week, four bright planets await your view at once as twilight fades. From right to left, they are Venus very low in the west-southwest, Jupiter in the southwest (upper left of Venus), Saturn in the south a little higher than Jupiter, and bright Mars lower in the…

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This Week’s Sky at a Glance, August 3 – 11

  Friday, August 3 • This week four bright planets shine at once during twilight, if you have low horizons in the right places. From right to left, they're Venus low in the west, Jupiter higher in the southwest, Saturn at about the same height in the south-southeast, and brilliant Mars low in the southeast.…

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This Week’s Sky at a Glance, July 27 – August 4

  Friday, July 27 • Full Moon (exact at 4:20 p.m. EDT). Full Moon is opposition Moon, so it shines with brilliant Mars, which is just a day past its opposition. Mars right now is 143 times farther from us than the Moon (and it's twice as large). Its surface is covered with rusty dark…

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This Week’s Sky at a Glance, July 20 – 28

  Friday, July 20 • The waxing gibbous Moon shines over Jupiter this evening, as shown here. Left of Jupiter by just 2° is the wide binocular double star Alpha Librae, magnitudes 2.8 and 5.1. The Moon is 1.3 light-seconds distant from us, and Jupiter is 44 light-minutes in its background. The two stars of…

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This Week’s Sky at a Glance, July 13 – 21

  Friday, July 13 • Cassiopeia is now well past its annual bottoming out due north. Look for its W pattern climbing low in the north-northeast after dark. The farther north you live, the higher it will be. Saturday, July 14 • As twilight fades, see if you can catch the Moon over Mercury very…

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This Week’s Sky at a Glance, July 6 – 14

  Friday, July 6 • As twilight fades, watch for Regulus coming into view 3½° to the left of Venus, as shown here. • After dark the central stars of the constellation Lyra, forming a small triangle and parallelogram, dangle to the lower right from bright Vega high in the east. The two brightest stars…

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This Week’s Sky at a Glance, June 29 – July 7

  Friday, June 29 • The waning gibbous Moon rises in the east-southeast in late twilight. An hour later, watch for Mars to clear the horizon about a fist at arm's length to the Moon's lower right (for North America). Saturday, June 30 • By late evening the Moon and Mars are arisen together, low…

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This Week’s Sky at a Glance, June 22 – 30

  Friday, June 22 • The waxing gibbous Moon this evening shines with bright Jupiter to its lower left and fainter Spica to its lower right. Saturday, June 23 • The bright "star" with the Moon tonight is Jupiter. Although they look rather close together, Jupiter is currently 1,800 times farther away — and it's…

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This Week’s Sky at a Glance, May 25 – June 2

  Friday, May 25 • As the waxing gibbous Moon crosses the sky tonight, Spica hangs below it, as shown in early twilight here. • The Arch of Spring spans the western sky in late twilight, arching over Venus. Pollux and Castor form the Arch's top; they're lined up over Venus roughly horizontally. Look well…