Northern backyard stargazers can get a good monthly guide to the heavens with this relaxing and easy on the ear Night Sky video. “Tonight’s Sky” is produced by, online home of the Hubble Space Telescope.

 Constellations, Deep-Sky Objects This Month

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

Moon crossing Taurus, March 3-5, 2017

The dark edge of the Moon will occult 1st-magnitude Aldebaran for most of the continental U.S. on the evening of March 4th. As always in these diagrams, the Moon is shows three times its actual apparent size.Friday, March 3

• The Moon hangs below Aldebaran, the Hyades, and the Pleiades in the west this evening. But get ready for tomorrow night, when. . . .

Saturday, March 4

• The dark limb of the first-quarter Moon occults (crosses over) orange Aldebaran for viewers in most of the contiguous United States, Mexico, and Central America. We’re calling this the best lunar occultation of 2017. See the March Sky & Telescope, page 48, or Aldebaran’s Disappearing Act online. Several fainter Hyades stars will also be occulted. Get world maps and local predictions (the UT dates are March 4th and 5th).

In addition, the International Occultation Timing Association has set up a special web page for the Aldebaran graze. It features interactive Google Maps of the occultation’s northern limit (graze line) from Rhode Island and Connecticut across upstate New York, the Great Lakes, and along the U.S.-Canada border to the Pacific. (For street-level precision of the graze line, choose the map for your elevation above sea level and follow the adjustment instructions.)

Sunday, March 5

• Now the Moon shines over Orion as the stars come out.

Monday, March 6

• It’s early March. So quite soon after dark now, the Big Dipper rises as high in the northeast as Cassiopeia has descended to in the northwest. Midway between them, as always, is Polaris.

Tuesday, March 7

• At nightfall, look below the Moon for Procyon and above the Moon for fainter Pollux and Castor.

Wednesday, March 8

• Bright Sirius now stands due south on the meridian just as twilight fades away into night. Sirius is the bottom star of the equilateral Winter Triangle. The other two stars of the Tiangle are orange Betelgeuse to Sirius’s upper right (Orion’s shoulder) and Procyon to Sirius’s upper left. The waxing gibbous Moon shines higher to the Triangle’s upper left.

Moon under Leo, March 9-12, 2017As the Moon waxes toward full (on the 12th), it shines under Leo.

Thursday, March 9

• The waxing gibbous Moon this evening shines to the right of the Sickle of Leo, as shown here.

Friday, March 10

• The bright Moon hangs a few degrees below or lower left of Regulus this evening. The Sickle of Leo extends upper left from Regulus.

• Late tonight comes the second-brightest asteroid occultation predicted this year for North America. A 6.3-magnitude star in Leo’s snout, just in front of the Sickle, should snap out of sight for up to 3 seconds for observers along a narrow track running from the Georgia coast to just north of San Francisco. The culprit is the 15th-magnitude asteroid 1343 Nicole, only about 26 km (16 miles) in diameter.

Leo will be very high in the southwest or south. For times, detailed maps, a finder chart for the star (easily spotted less than 1° northeast of Lambda Leonis), and other information, see Steve Preston’s prediction page for this event.

Saturday, March 11

• The Big Dipper glitters high in the northeast these evenings, standing on its handle. You probably know that the two stars forming the front of the Dipper’s bowl (currently on top) are the Pointers; they point to Polaris, currently to their left.

And, you may know that if you follow the curve of the Dipper’s handle out and around by a little more than a Dipper length, you’ll arc to Arcturus, now rising in the east.

But did you know that if you follow the Pointers backward the opposite way, you’ll land in Leo?

Draw a line diagonally across the Dipper’s bowl from where the handle is attached, continue far on, and you’ll go to Gemini.

And look at the two stars forming the open top of the Dipper’s bowl. Follow this line past the bowl’s lip far across the sky, and you crash into Capella.

• Daylight-saving time begins at 2 a.m. Sunday morning for most of North America. Clocks spring ahead.


Want to become a better astronomer? Learn your way around the constellations! They’re the key to locating everything fainter and deeper to hunt with binoculars or a telescope.

This is an outdoor nature hobby. For an easy-to-use constellation guide covering the whole evening sky, use the big monthly map in the center of each issue of Sky & Telescope, the essential guide to astronomy.

Pocket Sky Atlas, jumbo edition

The Pocket Sky Atlas

Once you get a telescope, to put it to good use you’ll need a detailed, large-scale sky atlas (set of charts). The basic standard is the Pocket Sky Atlas (in either the original or Jumbo Edition), which shows stars to magnitude 7.6.

Next up is the larger and deeper Sky Atlas 2000.0, plotting stars to magnitude 8.5; nearly three times as many. The next up, once you know your way around, is the even larger Uranometria 2000.0 (stars to magnitude 9.75). And read how to use sky charts with a telescope.

You’ll also want a good deep-sky guidebook, such as Sue French’s Deep-Sky Wonders collection (which includes its own charts), Sky Atlas 2000.0 Companion by Strong and Sinnott, or the bigger Night Sky Observer’s Guide by Kepple and Sanner.

Can a computerized telescope replace charts? Not for beginners, I don’t think, and not on mounts and tripods that are less than top-quality mechanically (meaning heavy and expensive).

And as Terence Dickinson and Alan Dyer say in their Backyard Astronomer’s Guide, “A full appreciation of the universe cannot come without developing the skills to find things in the sky and understanding how the sky works. This knowledge comes only by spending time under the stars with star maps in hand.”

The Pocket Sky Atlas plots 30,796 stars to magnitude 7.6 — which may sound like a lot, but it’s less than one per square degree on the sky. Also plotted are many hundreds of telescopic galaxies, star clusters, and nebulae. Shown above is the new Jumbo Edition for easier reading in the night. Click image for larger view.

 Skywatching Terms

  • Asterism: A noteworthy or striking pattern of stars within a larger constellation.
  • Degrees (measuring the sky): The sky is 360 degrees all the way around, which means roughly 180 degrees from horizon to horizon. It’s easy to measure distances between objects: Your fist on an outstretched arm covers about 10 degrees of sky.
  • Visual Magnitude: This is the astronomer’s scale for measuring the brightness of objects in the sky. The dimmest object visible in the night sky under perfectly dark conditions is about magnitude 6.5. Brighter stars are magnitude 2 or 1. The brightest objects get negative numbers. Venus can be as bright as magnitude minus 4.9. The full moon is minus 12.7 and the sun is minus 26.8.
  • Terminator: The boundary on the moon between sunlight and shadow.
  • Zenith: The point in the sky directly overhead.

Night Sky Observing Tips

  • Adjust to the dark: If you wish to observe faint objects, such as meteors or dim stars, give your eyes at least 15 minutes to adjust to the darkness.
  • Light Pollution: Even from a big city, one can see the moon, a handful of bright stars and sometimes the brightest planets. But to fully enjoy the heavens — especially a meteor shower, the constellations, or to see the amazing swath across the sky that represents our view toward the center of the Milky Way Galaxy — rural areas are best for night sky viewing.
  • If you’re stuck in a city or suburban area, a building can be used to block ambient light (or moonlight) to help reveal fainter objects. If you’re in the suburbs, simply turning off outdoor lights can help.
  • Prepare for skywatching: If you plan to be out for more than a few minutes, and it’s not a warm summer evening, dress warmer than you think necessary. An hour of observing a winter meteor shower can chill you to the bone. A blanket or lounge chair will prove much more comfortable than standing or sitting in a chair and craning your neck to see overhead.
  • Daytime skywatching: When Venus is visible (that is, not in front of or behind the sun) it can often be spotted during the day. But you’ll need to know where to look. A sky map is helpful. When the sun has large sunspots, they can be seen without a telescope. However, it’s unsafe to look at the sun without protective eyewear. See our video on how to safely observe the sun, or our safe sunwatching infographic.
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