This Week’s Sky at a Glance, April 24 – May 2

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

More than a month after it erupted, the nova in the Sagittarius Teapot continues to fluctuate between about magnitude 4.5 and 6. (As of April 30th it had taken another downturn to about 6.) If it's a "slow nova," it could become even brighter this summer. It's well placed in the south just before the beginning of dawn. See article with charts and up-to-date light curve.


Friday, April 24

The Moon tonight rests on (or near) one side of a big, almost equilateral triangle: bright Jupiter to the Moon's upper left, Pollux upper right of the Moon, and Procyon to the Moon's lower left.

As the Moon waxes past first quarter, it glides under Jupiter and the Sickle of Leo.

As the Moon waxes past first quarter, it glides under Jupiter and the Sickle of Leo.

Saturday, April 25

First-quarter Moon (exact at 7:55 p.m. EDT). Jupiter shines closer to the upper left of the Moon this evening. As the night grows late, the sky turns to put Jupiter directly above the Moon. Although they may look close together, Jupiter is nearly 2,000 times farther away — and 40 times larger in diameter.

Sunday, April 26

After dark now the Big Dipper has turned to lie almost upside down; face east-northeast and look very high. Its handle arcs around toward Arcturus a little more than a Dipper-length to the Dipper's lower right.

Monday, April 27

The waxing gibbous Moon shines under Regulus this evening, as shown here.

Among Jupiter's moons, telescope users in the western half of North America can watch the shadow of Io eclipse Europa from 10:59 to 11:02 p.m. PDT. At mid-eclipse, Europa will be dimmed by 1.4 magnitudes.

(Now that Jupiter is far from opposition, we see shadows in the Jovian system falling far enough sideways that an eclipsed satellite and its eclipser appear widely separated in a telescope's view. So we can see the eclipsed satellite dimming by itself, uncontaminated by the light of the eclipser. The tables in Sky & Telescope for these events presume that the two satellites appear blended and give their combined magnitude. See Bob King's article Catch the Last Best Antics of Jupiter’s Moons.)

Tuesday, April 28

Look very low in the northeast in twilight to catch the rising of Vega, the "Summer Star." By nightfall it's up in better view. Once Vega wins clear of the thick low air, it shines as the equal of Arcturus, the "Spring Star" high in the east very far to the upper right.

Wednesday, April 29

Far below the Moon at nightfall, and less far to the right of Spica, spot the springtime constellation Corvus: the four-star, sail-shaped Crow.

Thursday, April 30

Happy May Eve. As dusk fades, look for the Pleiades about 2° upper right of Mercury low in the west-northwest. Bring binoculars.

Friday, May 1

For May Day, Venus shines directly between the horn-tips of Taurus, Zeta and Beta Tauri (Elnath). It's closest to brighter Beta.

The Moon, two days from full, shines a few degrees above Spica this evening. Far off to their left or upper left is brighter Arcturus, pale yellow-orange.

Venus has just passed between the Zeta and Beta Tauri on May 2nd, and Aldebaran far below is lining up with Mercury. (These scenes are drawn for 40° north latitude. Far north or south of there, the scene will be tilted compared to this view.)

Venus has just passed between the Zeta and Beta Tauri on May 2nd, and Aldebaran far below is lining up with Mercury. (These scenes are drawn for 40° north latitude. Far north or south of there, the scene will be tilted compared to this view.)

Saturday, May 2

May is here, but wintry Sirius still twinkles low in the southwest as twilight fades — off the left edge of the scene above. How much later into the spring can you keep Sirius in view?

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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).

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.


This Week's Planet Roundup

Jupiter on April 13th.

Jupiter on April 13th. South is up. The South Equatorial Belt remains slightly wider than the North Equatorial Belt. The Red Spot Hollow has an unusual plume extending from its north (bottom) edge, and new white material has broken out in the Red Spot's turbulent wake. Image by Christopher Go.

Saturn on March 2, 2015

Saturn on March 2nd, imaged with superb resolution by Damian Peach during very good seeing. South is up. The dark North Polar Hexagon is distinctly hexagonal here — though its shape wasn't discovered until the Cassini spacecraft orbited Saturn!

 

Mercury (about magnitude –0.6) is having a fine apparition in evening twilight. Look for it very far to the lower right of Venus. Mercury gets a little higher every day, but it's also fading.

Venus (magnitude –4.1, in Taurus) blazes in the west during and after twilight — the brilliant "Evening Star." It doesn't set in the west-northwest until nearly two hours after dark. In a telescope Venus is still small and gibbous, but each week it grows and thins as it approaches us along its orbit.

Mars (magnitude +1.4) is disappearing deep in the sunset, to the lower right of much brighter Mercury. Use binoculars or a wide-field scope to say goodbye to it at last.

Jupiter (magnitude –2.1, in Cancer) shines high in the south as the stars come out, and less high in the southwest after dark. It's the second-brightest point of light in the sky after Venus. In a telescope, Jupiter has shrunk to 38 arcseconds wide.

Saturn (magnitude +0.1, just above the head of Scorpius) rises around the end of twilight and is highest in the south around 1 or 2 a.m. daylight-saving time. Below or lower left of Saturn by 9° is orange Antares, less bright. The next brightest star in the area is Delta Scorpii (about half as far from Saturn). Delta Sco is now in its 15th year of outburst!

Uranus is deep in the glow of dawn.

Neptune (magnitude +7.9, in Aquarius) is low in the east-southeast at the beginning of dawn. The farther south you are, the higher it will be.

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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.

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“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, April 24 – May 2

  1. mary bethmary beth

    Such beauty both morning and evening! Ringed Saturn adorning Scorpius is an entrancing way to start the day. At night the brilliant stage lights of Venus and Jupiter are showcasing Orion’s swan song with the Twins and dogs in supporting roles.. In (almost) a single field of vision I could see all this at twilight.. Aldebaran was twinkling beautifully as well. Above me was Regulus and the bright moon lighting the way for Arcturus and Spica, the Dipper set up concession in the North, so the entire evening sky has something to offer. Praise God for His creation!

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