This Week’s Sky at a Glance, March 27 – April 4

Some daily sky sights among the ever-changing Moon, planets, and stars.

Nova in Sagittarius rebrightens. The nova that peaked at about magnitude 4.3 on March 21–22, last week, then quickly dropped to 5.8, broke expectations by rebrightening to about 4.7 as of Thursday April 2nd. See article (with comparison-star chart) and up-to-date light curve. The nova is easy to observe with binoculars fairly low in the southeast just before the beginning of dawn.

Friday, March 27

This evening the Moon (just past first quarter) forms a big kite shape with bright Jupiter far to the Moon's left, Pollux to the Moon's upper left, and Procyon to its lower left.

Saturday, March 28

Now the Moon has moved inside the triangle of Jupiter, Pollux, and Procyon.

Watch the gibbous Moon pass Jupiter and Regulus as it waxes day by day.

Watch the gibbous Moon pass Jupiter and Regulus as it waxes day by day.

Sunday, March 29

Tonight the Moon and Jupiter cross the sky together. Although they look fairly near each other, looks in astronomy are deceiving. Jupiter is almost 1,800 times farther away than the Moon, and it's 40 times larger in diameter.

Monday, March 30

Watch Jupiter's satellite Europa emerge out of eclipse from Jupiter's shadow around 11:01 p.m. Eastern Daylight Time. With a telescope, watch for it to gradually glimmer into view a little off Jupiter's celestial eastern (following) limb.

Tuesday, March 31

The waxing gibbous Moon shines beneath Regulus and the Sickle of Leo early this evening, as shown at right. Farther upper right of the Moon shines bright Jupiter. By late evening, the sky rotates to place Jupiter to the Moon's right.

The shadow of Callisto slowly crosses Jupiter's face tonight from 11:14 p.m. to 3:57 a.m. EDT.

Wednesday, April 1

The coming of April always finds Orion in the southwest at dusk, leaning over with his three-star belt almost horizontal (depending on your time and latitude). The belt points left toward bright Sirius, and to the right toward Aldebaran and, farther on, the Pleiades.

Now the Moon moves through Virgo pasr Gamma Vir and Spica. The blue 10° scale bar is about the width of your fist at arm's length.

Now the Moon moves through Virgo past Gamma Vir and Spica. The blue 10° scale bar is about the width of your fist at arm's length.

Thursday, April 2

Look above Venus at nightfall for the Pleiades star cluster, the size of your fingertip at arm's length. It's 8° above Venus this evening. It will pass Venus by less than 3° on April 10th through 12th.

Friday, April 3

A total eclipse of the Moon happens before or during dawn Saturday morning for the western half of North America; the farther west you are the better. It happens during Saturday evening for Australia and the Far East. This eclipse is barely total and for only about 12 minutes, from about 11:54 to 12:06 April 4th UT (GMT). Partial eclipse begins at 10:15 UT and ends at 13:45 UT. For maps and more, see the April Sky & Telescope, page 50, or the version online: Preview of April 4th’s Total Lunar Eclipse.

Can't see the eclipse from where you are? Griffith Observatory in Los Angeles will run a live webcast from 5:00 a.m. to 9:30 a.m. Eastern Daylight Time (9:00 to 13:30 April 4th UT). The Virtual Telescope Project will also webcast the eclipse, starting at 6:00 a.m. EDT (10:00 UT). So will Slooh, also starting at 6:00 a.m. EDT (10:00 UT).

On Friday evening for North America, the full Moon shines in Virgo with Spica well to its lower left, as shown here. Much closer to the Moon is fainter Gamma Virginis (Porrima), a close telescopic double star.

Saturday, April 4

The Moon is still essentially full this evening, now much closer to Spica.

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. 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 it's still less than one per square degree on the sky. Also plotted are many hundreds of telescopic galaxies, star clusters, and nebulae.

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 once you know your way around, 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, 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, which means fairly heavy and expensive). 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."

This Week's Planet Roundup

Jupiter on March 17, 2015

On March 17th, two white outbreaks dominated the turbulent wake of the Great Red Spot on its following (celestial eastern) side (to the right here). South is up. The Red Spot Hollow was wide and light-colored. Far below, in the narrow, broken North Temperate Belt, the thin, dark red barge had become more elongated than it was a few weeks ago. These images (by Christopher Go) have been sharpened and contrast-boosted.

Jupiter on April 1, 2015

On April 1st, Io and its shadow were both crossing Jupiter when Christopher Go took this image at 11:17 UT. The turbulent wake following the Great Red Spot has nearly returned to normal, and the dark area preceding the spot has grown a bit darker.

Mercury is hidden in the glare of the Sun.

Venus (magnitude –4.0) blazes in the west during and after twilight — the unmistakable "Evening Star." It doesn't set in the west-northwest until a good hour and a half after complete dark. Look for the Pleiades above it, closer every day. The little cluster will pass to Venus's right on April 10th and 11th.

Mars (magnitude +1.4, less than 1% as bright as Venus) is gradually sinking farther down to the lower right of Venus in twilight. It's 15° below Venus on March 27th and 18° below it by April 3rd.

Jupiter (magnitude –2.4, in Cancer) shines high in the south at dusk. It's the brightest point of light on that side of the sky. In a telescope Jupiter is still 42 or 41 arcseconds wide. Don't expect to see nearly the detail with your eye that video-frame stacking with a large amateur telescope can bring out, such as in the fine image here!

Saturn (magnitude +0.3, at the head of Scorpius) rises around 11 or midnight daylight-saving time and is highest in the south in early-morning hours. Below or lower left of Saturn, by 8°, is orange Antares, not quite as bright.

Look just ½° below Saturn for Nu Scorpii, a showpiece double star for telescopes. And less than 2° to their right or lower right is Beta Scorpii, an even finer telescopic double.

Uranus and Neptune are out of sight in the glare of the Sun.

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) is Universal Time (UT, UTC, or GMT) minus 4 hours.

“This adventure is made possible by generations of searchers strictly adhering to a simple set of rules. Test ideas by experiments and observations. Build on those ideas that pass the test. Reject the ones that fail. Follow the evidence wherever it leads, and question everything. Accept these terms, and the cosmos is yours.”

— Neil deGrasse Tyson, 2014.


One thought on “This Week’s Sky at a Glance, March 27 – April 4

  1. mary bethmary beth

    This is a wonderful page! Love all the information. On a fun note, the moon looked like an olive in a martini glass Saturday evening, inside the triangle of Jupiter, Procyon and Pollux, with Sirius completing the stem of the glass :)!

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