Sky at a Glance | March 29th, 2013

Some night sky sights for March 29 – April 6

11 p.m. view
With the Moon waning away from full, it rises ever later as it moves past Spica and Saturn.
9 p.m. view
Jupiter used to shine between Aldebaran and the Pleiades. But now it's moving eastward against the background stars and starting to leave them behind.

Friday, March 29

  • The waning Moon rises in the east around 11 or later this evening, depending on your location. Look above it for the planet Saturn, as shown below.

  • This is the time of year when the dim Little Dipper juts to the right from Polaris (the Little Dipper's handle-end) during evening hours. The Big Dipper, much brighter, curls over high above it, "dumping water" into it.

    Saturday, March 30

  • Algol in Perseus is heading down in the northwest after dusk. Your last good chance to catch Algol in one of its eclipses this season, at least from North America, may be this evening. Algol should be at minimum brightness, magnitude 3.4 instead of its usual 2.1, for a couple hours centered on 9:32 p.m. Eastern Daylight Time, favoring the eastern half of the continent. Algol takes several additional hours to fade and to rebrighten.

  • Early Sunday morning, telescope users south of a line from central Florida through Oregon can watch the double star Beta Scorpii, magnitudes 2.6 and 4.8, emerge from behind the dark limb of the waning gibbous Moon. Map and timetables (for the bright component; the faint one emerges up to a minute or two earlier. Times are in Universal Time. Be sure to scroll down there to find the Reappearance timetable.)

    Sunday, March 31

  • Following Sirius and Canis Major westward across the sky is Milky-Way-rich Puppis. Now that the Moon is gone, get out your scope and hunt the open clusters and nebulae of Puppis with Sue French's Deep-Sky Wonders article and chart in the March Sky & Telescope, page 56.

    Monday, April 1

  • The red carbon stars U and V Hydrae, and the Ghost of Jupiter planetary nebula (magnitude 7.7), all reside within a few degrees of each other in central Hydra. See Gary Seronik's Binocular Highlight column and chart in the April Sky & Telescope, page 45 (and for more on the Ghost of Jupiter, page 56).

    Tuesday, April 2

  • As spring advances, wintry Orion tilts farther over as it declines in the west-southwest after dark. Orion's Belt in its middle is almost horizontal. Orion is brightly framed between Jupiter on its right and Sirius on its left.

  • Last-quarter Moon tonight (exact at 12:37 a.m. Wednesday morning EDT).

    Wednesday, April 3

  • Jupiter's moon Io crosses Jupiter's face from 7:56 to 10:08 p.m. EDT, followed by its tiny black shadow (much more visible) from 9:03 to 11:15 p.m. EDT.

    Thursday, April 4

  • This evening Comet PanSTARRS, fading every day, is passing 2° west (lower right) of the Andromeda Galaxy, M31. They may appear about equally dim low in the northwest just as twilight is ending, for observers at fairly high northern latitudes. Think photo opportunity.

    Friday, April 5

  • The huge, bright Winter Hexagon is still in view after dark, filling the sky to the southwest and west. Start at bright Sirius in the southwest. It marks the Hexagon's lower left corner. High above Sirius is Procyon. From there, look upper right to Pollux and Castor, lower right from Castor to Menkalinen and Capella, lower left to Aldebaran (with brighter Jupiter hogging the limelight near it!), lower left to Rigel at the bottom of Orion, and back to Sirius.

    Saturday, April 6

  • Look for Arcturus, the "Spring Star," low in the east-northeast in twilight and higher in the east after dark. The constellation Bootes extends to its left. High to Arcturus's upper left is the Big Dipper.


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

    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. Or download our free Getting Started in Astronomy booklet (which only has bimonthly maps).

    Pocket Sky Atlas
    The Pocket Sky Atlas plots 30,796 stars to magnitude 7.6 — which may sound like a lot, but that's less than one star in an entire telescopic field of view, on average. By comparison, Sky Atlas 2000.0 plots 81,312 stars to magnitude 8.5, typically one or two stars per telescopic field. Both atlases include many hundreds of deep-sky targets — galaxies, star clusters, and nebulae — to hunt among the stars.
    Sky & Telescope

    Once you get a telescope, to put it to good use you'll need a detailed, large-scale sky atlas (set of charts). The standards are the little Pocket Sky Atlas, which shows stars to magnitude 7.6; the larger and deeper Sky Atlas 2000.0 (stars to magnitude 8.5); and the even larger Uranometria 2000.0 (stars to magnitude 9.75). And read how to use sky charts with a telescope effectively.

    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, the bigger Night Sky Observer's Guide by Kepple and Sanner, or the beloved if dated Burnham's Celestial Handbook.

    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 (able to point with better than 0.2° repeatability). As Terence Dickinson and Alan Dyer say in their invaluable 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."


    This Week's Planet Roundup

    Jupiter on April 4, 2013
    Jupiter's orange Oval BA was near the central meridian when Christopher Go took this image on April 4th. (The System II longitude on the central meridian was 115°.) Three dark-rimmed white ovals follow behind it. Below it in the North Equatorial Belt, note the small, bright white outbreak. South is up.

    Mercury (magnitude +0.2) is having a poor apparition very low in the dawn. Look for it just above the east-southeast horizon about 30 minutes before sunrise.

    Venus and Mars remain hidden in the glare of the Sun.

    Jupiter (magnitude –2.1, in Taurus) comes into view high in the west after sunset, then descends as night grows late. Lower left of Jupiter is fainter orange Aldebaran. Farther to Jupiter's lower right are the Pleiades. They all set in the west-northwest around the middle of the night. In a telescope, Jupiter has shrunk to 36 arcseconds wide.

    Saturn (magnitude +0.2, in Libra) rises in the east-southeast only about a half hour after the end of twilight now. Watch for it to make its appearance well to the lower left of Spica, and farther to the lower right of brighter Arcturus. Saturn shines highest in the south around 2 or 3 a.m. daylight saving time — more or less between Spica to its right, and Delta Scorpii (and then Antares) to its lower left. Saturn will come to opposition on the night of April 27th.

    Uranus and Neptune are out of sight in the dawn.


    All descriptions that relate to your horizon — including the words up, down, right, and left — are written for the world's mid-northern latitudes. Descriptions that also depend on longitude (mainly Moon positions) are for North America. Eastern Daylight Time (EDT) equals Universal Time (also known as UT, UTC, or GMT) minus 4 hours.


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