Friday, May 1

■ As the stars come out this evening, look for Regulus under the Moon as shown below. The next brightest star in Leo's Sickle is yellow-orange Gamma Leonis, Algieba, also shown.

As the evening grows late, watch their arrangement rotate clockwise. And also watch the Moon creep slightly to the east with respect to the stars. As seen from Earth, the Moon moves along its orbit by about its own apparent diameter per hour.

Moon crossing Leo, May 1-2, 2020
The waxing Moon crosses Leo as it turns gibbous. The blue 10° scale is about the width of your fist at arm's length. The Moon in these scenes is always drawn about three times its actual apparent size. And it's positioned exactly for a skywatcher at latitude 40° north, longitude 90° west, near the middle of North America.

■ All week, look high in the west at nightfall for Pollux and Castor, the heads of the Gemini twins. They're lined up almost horizontally (depending on your latitude), some 30° upper left of brilliant Venus: about three fists at arm's length.

Pollux and Castor form the top of the enormous Arch of Spring. To their lower left is Procyon, the left end of the Arch. Farther to their lower right is the other end, formed by Menkalinan (Beta Aurigae) and then brilliant Capella.

Venus shines below the Arch's right side.

Jupiter, Saturn, Mars before dawn, early May 2020
The three bright outer planets continue to shine before dawn, though Mars is pulling farther away from Jupiter and Saturn. The top star in Capricornus here is Alpha Cap, a fine, easy binocular double star that you might even split with the unaided eye. Beta Cap just below it is also a binocular double, though less easy to split; its components are very unequal, and they are only half as far apart (in almost the same orientation).

Saturday, May 2

■ Although it's May now, wintry Sirius still twinkles low in the west-southwest in late twilight. It sets soon after. How much longer into the spring can you keep Sirius in view? In other words, what will be its date of "heliacal setting" as seen by you? A lot depends on your latitude: The farther north you are, the sooner it'll go.

Sunday, May 3

■ Three zero-magnitude stars shine after dark in May: Arcturus high in the southeast, Vega much lower in the northeast, and Capella in the northwest (upper right of Venus). They appear so bright because each is at least 60 times as luminous as the Sun, and because they're all relatively nearby: 37, 25, and 42 light-years away, respectively.

Monday, May 4

■ The brightest star below the Moon after dark is Spica. Farther to the Moon's left or upper left is brighter Arcturus.

Just 2° or 3° to the right of the Moon after dark for North America, look for fainter, 3rd-magnitude Gamma Virginis (Porrima). It's a fine, tight telescopic double star: two equal components currently separated by 3.0 arcseconds. Porrima is currently widening by 0.1 arcsecond each year.

■ The Eta Aquarid meteor shower should be at its peak in the hour or so before Tuesday's dawn. The Southern Hemisphere always has the best view of this shower, but this year even mid-northern skywatchers may be in for something a little special. Jupiter's gravity tugs on part of the meteor stream every 12 years, with the result that a richer part of the stream may intersect Earth this year and the next two.

But on the downside, the bright, nearly-full Moon doesn't set until after dawn is already in progress. So don't count on more than one meteor being visible every 5 or 10 minutes even if you're watching steadily, for instance by lying back in a lawn chair. See the May Sky & Telescope, page 50.

Tuesday, May 5

■ This evening, if you're in North America, draw a line from the Moon through Spica some 7° to its left or lower left. Continue the line on at least twice as far, and you're more or less at Corvus, the springtime Crow. Its four brightest stars have always been described in astronomy guides as "sail-shaped." That would be a sail that's gaff-rigged, a shape immediately recognized by our several-times-great-grandparents but less so now. What do you think this asterism might be in the 21st century? The Smashed Amazon Box?

Wednesday, May 6

■  Full Moon both this evening and tomorrow evening; the Moon is exactly full at 6:45 a.m. Thursday morning EDT. It's a supermoon, just a trace larger than average, because it's at perigee on the 6th.

As the stars begin to come out this evening, the Moon is low in the east-southeast. Look for Arcturus high to its upper left and Spica, not quite as bright, less far to the Moon's upper right.

Thursday, May 7

■  A gigantic asterism you may not know about is the Diamond of Virgo, some 50° tall and extending over five constellations. It now stands upright in the south after the stars come out. Start with Spica, its bottom. Upper left from Spica is bright Arcturus. Almost as far upper right from Arcturus is fainter Cor Caroli, 3rd magnitude. The same distance lower right from there is Denebola, the 2nd-magnitude tailtip of Leo. And then back to Spica.

The bottom three of these stars, the brightest, form a nearly perfect equilateral triangle. Maybe we should call this the "Spring Triangle" to parallel those of summer and winter?

Friday, May 8

■ The waning gibbous Moon rises in the east-southeast around 10 p.m. daylight-saving time, depending on where you live in your time zone. Once it's well up, look to its right or lower right for Antares, twinkling pale orange. Around and to the upper right of Antares are lesser, whiter stars of upper Scorpius.

Saturday, May 9

■ Summer is still six weeks away, but the Summer Triangle is beginning to make its appearance in the east, one star after another. The first in view is bright Vega. It's already visible low in the northeast as twilight fades.

Next up is Deneb, lower left of Vega by two or three fists at arm's length. Deneb takes about an hour to appear after Vega does, depending on your latitude.

The third is Altair, which shows up far to their lower right by midnight.

This Week's Planet Roundup

Mercury is still out of sight in conjunction with the Sun. But just wait. Later this month it will emerge into evening twilight view and pair up with Venus on May 21st.

Venus (magnitude –4.7, in north-central Taurus) is the bright white "Evening Star" in the west during and after dusk. It's still shining at its brightest.

Look upper right of Venus for Capella, about two fists at arm's length away. A bit farther to Venus's left is Betelgeuse.

Much closer above Venus is Beta Tauri (El Nath), fainter at magnitude 1.6. Venus creeps a little closer to Beta this week (from 3.3° to 1.6° ), then stalls out without quite reaching it. Next week Venus will start falling back away.

Meanwhile the whole scene is sinking lower. On May 1st Venus remains shining in the northwest for about 1½ hours after the end of twilight, but by the 8th it sets only about an hour after the last trace of daylight is gone.

In a telescope, meanwhile, Venus is growing more dramatic. This week its crescent enlarges from 39 to 44 arcseconds in diameter, while waning in phase from 24% to just 18% sunlit. It's on its way down to conjunction with the Sun on June 3rd.

Jupiter on April 11, 2020, imaged by Christopher Go. South here is up. The Great Red Spot is still quite intact, after its drama last year when it appeared to shell fragments of orange stuff. Pale tan material still fills the Equatorial Zone, usually white.
Jupiter on April 11th, imaged by Christopher Go. South is up. The Great Red Spot is fully intact, despite the drama last year when it appeared to shed arcs of its orange material. The Equatorial Zone, normally white, still has a pale tan cast.
Jupiter's non-Red-Spot side, imaged by Christopher Go on April 22, 2020
The other side of Jupiter, imaged by Go on April 22nd. Again south is up. The satellite is Ganymede; its south polar bright spot stands out in this contrast-enhanced view. "The North Equatorial Belt looks very strange," writes Go. "The southern part is dark red but the northern part looks very disturbed."

Mars, Jupiter, and Saturn (magnitudes, +0.4, – 2.4, and +0.5, respectively) shine in the southeast before and during early dawn.

Jupiter, the brightest, is on the right. Before dawn begins, spot the Sagittarius Teapot to the right of it.

Saturn glows pale yellow 5° to Jupiter's left.

Mars is much farther to Saturn's lower left. It's moving away from the other two. On the morning of May 2nd Mars is 21° from Saturn; by the 9th it's 25° away.

Uranus is hidden behind the glare of the Sun.

Neptune, a mere 8th magnitude, is barely risen in the east as dawn begins.

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, GMT, or Z time) minus 4 hours.

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.

Jumbo Pocket Sky Atlas cover
The Pocket Sky Atlas plots 30,796 stars to magnitude 7.6, and hundreds of telescopic galaxies, star clusters, and nebulae among them. Shown above is the Jumbo Edition for easier reading in the night. Sample chart.

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, are the even larger Interstellarum atlas (stars to magnitude 9.5) and 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 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."

Audio sky tour. Out under the evening sky with your earbuds in place, listen to Kelly Beatty's monthly podcast tour of the heavens above. It's free.


Image of Anthony Barreiro

Anthony Barreiro

May 1, 2020 at 5:43 pm

I think Corvus looks like a sail. There are still gaff-rigged schooners sailing on San Francisco Bay, up and down the coast, and beyond. If your sky is dark enough to add Alpha and Eta Corvi to the stick figure, Corvus even look like a bird, with Gamma Corvi as the head, Eta and Alpha as the wing tips, and Beta as the tail. If you can't see a bird or a sail, just look for a quadrilateral.

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May 2, 2020 at 9:51 am

Last night, the skies here in Maryland cleared up and near sunset, I was out 2000-2100 EDT. I enjoyed some 10x50 binocular viewing on a large horse farm, my neighbor's next to me. Lovely views of waxing gibbous Moon in Leo, Regulus, Sirius, and Venus. Venus angular size (39") much larger now so distinct, planet shape, crescent shape compared to binocular views of Sirius as an example. Don't forget, Saturn starts retrograde on 11 of May and Jupiter follows going retrograde on 14 of May. Mars continues eastward so if you can, enjoy those planet dances as they switch up and move in different directions in the morning sky :)--Rod

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Pencil BFB

May 3, 2020 at 2:22 am

Yes, there IS a Spring Triangle, involving Arcturus, Spica, and Regulus. More on that here:

Also, I notice the "2" added to the end of the url, e.g.

I think it'd have been better if the title want something like "May 1 - 9, 2020" instead.

Also, when I was observing a few months ago, I saw Venus around 15 minutes before sunset. Last year, around Jupiter's eastern quadrature, I was able to spot the planet 5 minutes before sunset. I didn't use binoculars or a telescope for both of those observations. It's because of their brightness.

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mary beth

May 5, 2020 at 1:58 am

I’ve seen the planets during the day a few times in my life and it’s really amazing! A few years ago, I believe it was Jupiter that was very bright... and you could see it at 3 o’clock in the afternoon if you knew where to look! thank you for the info on the spring triangle. Now we need to come up with an autumn one, all the seasons will be geometrically covered!

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May 7, 2020 at 12:01 pm

mary beth, I did briefly see the Full Flower, Corn, Milk, super-duper Moon early this morning. Clear skies and I viewed Mars, Saturn, Jupiter using my telescope, 0500-0600 EDT along the ecliptic. The Full Moon or nearly Full Moon at 1045 UT, very low in WSW sky in Libra, setting about 0620 EDT for me. I could see it through some trees in my east pasture while viewing the planets with my telescope. However, Jupiter was the much better show here this morning in my eyepiece along with Saturn and Titan moon 🙂

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mary beth

May 5, 2020 at 2:00 am

Today was my birthday and we were sitting outside enjoying the beautiful moon and a lovely summery breeze in the late Nautical twilight sky. I was looking at Venus and I saw the most incredible meteor. It was huge and lasted quite a while. Perfect birthday present! I had forgotten about the Eta Aquarid meteor shower peaking tonight. Rod I hope you and some of the others are enjoying!

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May 6, 2020 at 8:22 am

mary beth, happy B-Day 🙂 No, last good weather for me was 04-May in the early evening time when I used my telescope and enjoyed Elnath, Venus, and waxing gibbous Moon in Virgo then the clouds came back. Mostly clouds and rain now. Perhaps this Saturday will be better but I will spend plenty of time cutting and whacking weeds too like I did on the 2nd of May. I will operate in power cut up everything mode 🙂

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mary beth

May 6, 2020 at 4:57 pm

Thank you Rod! Sounds like you’ll miss the full moon...I’ll try to give you a detailed description...looking reel good here. We had a cool front that makes it less humid and real clear. Great time of year!

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