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

This Week’s Sky at a Glance, July 25 – August 2

Friday, July 25 Mars and Spica shine in the southwest at nightfall. Mars keeps pulling farther away from Spica; they're now 6° apart. Saturn glows pale yellow to their upper left. Arcturus sparkles high to their upper right. Saturday, July 26 New Moon (exact at 6:42 p.m. EDT). Summer is hardly more than a...

This Week's Sky at a Glance

This Week’s Sky at a Glance, July 11 – 19

Friday, July 11 Mars and Spica form a striking pair in the southwestern sky at dusk! They're now just under 2° apart. On Sunday evening they'll be at their minimum separation, 1.3°. Watch them change day by day. Full Moon tonight and Saturday night (exactly full at 7:25 a.m. Saturday morning Eastern Daylight Time.)...

This Week's Sky at a Glance

This Week’s Sky at a Glance, July 4-12

Friday, July 4 Out to watch fireworks? As you're waiting for twilight to end, spot the Moon in the west-southwest with Mars and Spica off to its left, as shown for July 4 here. High above them all shines brighter Arcturus. Saturn is farther left (off the left edge of this illustration). Point them...

This Week's Sky at a Glance

This Week’s Sky at a Glance, June 27 – July 5

Friday, June 27 This is the time of year when, at the end of dusk, the dim Little Dipper floats straight upward from Polaris (the end of its handle) — like a helium balloon on a string, escaped from some summer evening party. Look due north. (Through light pollution, all that you may see...

This Week's Sky at a Glance

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

Friday, June 13 Vega is the brightest star shining in the east after dusk. It's currently the top star of the big Summer Triangle. The brightest star to Vega's lower left is Deneb. Look farther to Vega's lower right for Altair. The Summer Triangle will climb higher in early evening all through the summer,...

This Week's Sky at a Glance

Sky at a Glance, June 6 – 14

Friday, June 6 Look left of the Moon this evening for Mars, then Spica, as shown at right. With June under way, the Big Dipper is swinging around after dark to hang down by its handle high in the northwest. The middle star of its handle is Mizar, with tiny little Alcor right next...

Planck temperature map of universe

What’s Next for Inflation Cosmology – New Updates!

Our July cover story is the apparent discovery of gravitational waves from the instant of inflation when the Big Bang took shape. The article just scratches the surface of this incredible topic — and since it was printed, a serious challenge to the discovery has been raised. Here are more links regarding what could...

This Week's Sky at a Glance

Sky at a Glance, May 23 – 31

Friday, May 23 Meteor Update Saturday morning: Well that was a dud! Meteor watchers all over North America who went out in the early morning hours for the new predicted Camelopardalid shower saw few if any. People indeed reported observing a handful of meteors from the new radiant, but just a few per hour....

This Week's Sky at a Glance

Sky at a Glance, May 16 – 24

Friday, May 16 Look for Mercury as twilight darkens. It's low in the west-northwest, far to the lower right of Jupiter and lower left of Capella. Mercury is having its highest showing of 2014 (for skywatchers at mid-northern latitudes). Saturday, May 17 Arcturus shines high in the southeast these nights. Vega shines much lower...

This Week's Sky at a Glance

Sky at a Glance, May 9 – 17

Friday, May 9 The waxing gibbous Moon in the evening sky forms a curving line with Mars to its left, and Spica to the lower left of Mars. Saturday, May 10 Bright Mars shines left of the Moon. Although they look rather close together, Mars is 260 times farther away — and twice as...

View of Saturn through a large backyard telescope

See Splendid Saturn at Its Best

Your first view of Saturn with a telescope can introduce you to the riches of stargazing — and now is the perfect time to observe it. Saturn is entering the early evening sky this spring just as Jupiter begins its exit in the west. Here's a quick guide to spotting the ringed planet by...

This Week's Sky at a Glance

Sky at a Glance, May 2 – 10

Friday, May 2 How soon after sunset can you see the first stars and planets coming out? The brightest this spring is Jupiter. Look for it high in the west, almost two fist-widths at arm's length above or upper left of the Moon this evening. Next brightest is Sirius, sinking in the southwest. Saturday,...

This Week's Sky at a Glance

Sky at a Glance, April 18-26

Friday, April 18 Jupiter shines right under the big Arch of Spring this year. The Arch spans much of the western sky. Pollux and Castor form its top (as seen from mid-northern latitudes). To their lower left is Procyon, one end of the Arch. Farther to their lower right is the other end: Menkalinen...

Art of Sylvia 87 and two moons

The asteroid occultation of July 19, 2014

As told in the July 2014 Sky & Telescope, on the morning of July 19th an 8.7-magnitude star in Pisces will vanish for up to 4 seconds behind the invisibly faint asteroid 611 Valeria, as seen from a track crossing northern Mexico, Texas, the Deep South including the Atlanta area, and the Carolinas. The...