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 and then bright Capella.

Saturday, April 19

Have you said hello to Vega yet this year? The "Summer Star" is now sparkling low in the northeast at nightfall. By dawn it's high overhead.

Big Dipper photo

The Big Dipper, very high in the north, is turned to "dump water" in the evening.
Akira Fujii / Sky & Telescope

Sunday, April 20

The Big Dipper floats upside down near the top of the sky these evenings (for skywatchers at mid-northern latitudes), as though pouring out April showers to bring May flowers.

Vesta, the brightest asteroid, and Ceres, the biggest one, are both barely past opposition. They're just 2½° apart in eastern Virgo, easy targets in binoculars at magnitudes 5.9 and 7.0. Use our finder chart for Ceres and Vesta (click the link in the text for "printable finder chart for Ceres and Vesta in 2014").

Monday, April 21

Last-quarter Moon (exact at 3:52 a.m. Tuesday morning Eastern Daylight Time). The Moon rises around 2 a.m. local time Tuesday morning, far below Altair near the wide double stars Alpha and Beta Capricorni.

The weak Lyrid meteor shower should be active in the moonlight before dawn. Even in years with no moonlight, meteor watchers usually report fewer than 20 Lyrids visible per hour.

Tuesday, April 22

Bright Jupiter, high in the west at dusk, forms the top of a huge, sideways-compressed pentagon with other bright celestial landmarks. Look left of Jupiter for Procyon, far below Procyon for bright Sirius, to the right of Sirius and somewhat lower for Rigel in Orion's foot, then above Rigel for Betelgeuse, and back to Jupiter.

Venus with the Moon at dawn

Watch the waning Moon march sunward past Venus low in early dawn. Sky & Telescope diagram

Wednesday, April 23

As soon as twilight fades out, look moderately low in the west-northwest (far below Capella) for the little Pleiades star cluster, the size of your fingertip at arm's length. How much later through the spring can you follow the Pleiades before they're lost in the sunset?

Thursday, April 24

During dawn tomorrow morning (the 25th), look below the waning crescent Moon for Venus, as shown at right. Think photo opportunity!

Friday, April 25

At dawn Saturday morning, spot the thin crescent Moon low in the east left of Venus.

Saturday, April 26

Brilliant Mars has been drawing closer to Gamma Virginis (Porrima), magnitude 2.7. Look for it about 2° to Mars's upper right after dark. They'll appear closest (1.4° apart) on May 4th and 5th. Gamma Vir is a fine, tight telescopic double star with a current separation of 2.1 arcseconds. Take a look at it with your scope at high power after you're done with Mars!

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 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

Mars on April 8th, imaged by Anthony Wesley

Mars on April 8th, imaged by Anthony Wesley. South is up. Syrtis Major is the big, dark downward "peninsula" near center. Clouds cover Hellas at top and Elysium at left. The North Polar cap has shrunk, exposing the dark band around it. Anthony Wesley.

Mercury is hidden in conjunction with the Sun.

Venus (magnitude –4.2) is the bright "Morning Star" shining in the east-southeast during dawn. How late into the growing daylight can you follow it?

Mars, just past opposition, blazes at magnitude –1.4 in the southeast during evening, with Spica below it. Mars is highest in the south around midnight daylight saving time.

Now's the time for Mars in a telescope! It's still 15 arcseconds wide this week, not exactly large even at high power, but the largest it will appear until 2016. The higher in the sky Mars is, the sharper it will generally appear in a telescope. See the Mars map and observing guide in the March Sky & Telescope, page 50. Use our Mars Profiler to find which side of the planet will be facing you when you plan to observe it.

Jupiter on April 18, 2014

Jupiter on April 18th. South is up. The tiny white dot on the central meridian, and on the south edge of the South Equatorial Belt, is Europa crossing in front of Jupiter. Christopher Go.

Jupiter (magnitude –2.1, in central Gemini) shines even brighter than Mars, high in the southwest in twilight. It sinks westward through the evening and sets around 1 or 2 a.m. In a telescope it has shrunk to 36″ across its equator.

Saturn (magnitude +0.2, in the center of Libra) rises around the end of twilight and is highest in the south around 2 a.m. By then it's far left of Mars, and half as far to the upper right of Antares.

Uranus and Neptune are still low in the glow of sunrise.

Watch our SkyWeek TV short, soon coming to an end!

"We may be little guys, but we don’t think small. It’s the courage of questions, of grasping our true circumstances, and not pretending we are at the center of it all, that is adulthood."
— Ann Druyan, 2014. The remade Cosmos series continues on Sunday nights. Watch online anytime.

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.

2 thoughts on “Sky at a Glance, April 18-26

  1. jplatzer

    This morning on the way to work, around 5:30 AM in Connecticut, I saw a very bright star in a south to southeasterly direction. It was the only one in the sky. It was in roughly the same spot as Arcturus last night but was white instead of orange. I had thought it might be Arcturus but after reading Alan’s post above, I think it might have been Venus. Did anyone else see it?