Supernova in NGC 3621 in Hydra. Supernova 2024ggi, discovered a month ago, quickly reached visual magnitude 12.0, stayed there for a couple weeks, and is now beginning to drift down slightly (12.3 as of May 2nd). See the AAVSO's table of recent observations for updates.

NGC 3621, glowing at 10th magnitude, is rather far south at declination –33°. But it crosses the meridian soon after dark. For charts See Bob King's Jupiter meets Uranus in twilight; Supernova erupts in nearby galaxy.


FRIDAY, MAY 3

■ After sunset, use binoculars or a wide-field telescope to try for one last look at Jupiter. It's just above the west-northwest horizon in bright twilight. (Everything else in that area will be completely invisible.) If you succeed, you will be among the few people on Earth to see the giant planet so close to the end of its 2023-24 apparition.

■ On the opposite side of the Sun, low in eastern dawn sky, Saturday morning May 4th finds the waning crescent Moon hangings between Saturn to its upper right and Mars to its left or lower left, as shown below.

Waning crescent Moon passing Saturn and Mars in the dawn, May 3-6, 2024
Low in the brightening dawn, the waning crescent Moon passes Saturn, then Mars, then very challenging Mercury.

SATURDAY, MAY 4

■ The Eta Aquariid meteor shower, bits of the rubble stream shed by Halley's Comet, often presents the best meteor display of the year for the Southern Hemisphere. But for us northerners the shower's radiant point is still quite low even as dawn begins. Nevertheless, meteor watchers in the southern U.S. may catch the death streaks of a few Halley bits before dawn on May 5th and 6th. See the May Sky & Telescope, page 48.

SUNDAY, MAY 5

■ A gigantic spring asterism you may not know is the Great Diamond, some 50° tall and extending over five constellations. It now stands upright in the southeast to south after dusk. Its stars are magnitudes 0, 1 ,2 and 3.

Start with Spica, its bottom, mag 1. Upper left from Spica is brighter Arcturus, mag 0. Almost as far upper right from Arcturus is Cor Caroli, 3rd magnitude. The same distance lower right from there is Denebola, the 2nd-magnitude tailtip of Leo. And then back to Spica. Robert H. Baker may have been the first to name the Great Diamond, in his 1954 book When the Stars Come Out.

The bottom three of these stars, the brightest, form a nearly perfect equilateral triangle. We can call this the "Spring Triangle" to parallel to those of summer and winter. The first to name it such was probably the late Sky & Telescope columnist George Lovi, writing in the March 1974 issue and again in May 1977. It didn't catch on, so let's try again.

Haze on the Diamond's edge: If you have a dark sky, or binoculars, look halfway from Cor Caroli to Denebola for the very large, sparse Coma Berenices star cluster. It spans some 4°, about the size of a ping-pong ball held at arm's length.

MONDAY, MAY 6

■ Face north as the stars come out, look very high, and you'll find the Pointers, the end stars of the Big Dipper's bowl, on the north meridian pointing toward Polaris straight down below. From the Pointers to Polaris is about three fists at arm's length.

TUESDAY, MAY 7

■ The Sombrero Galaxy, M104, is one of the most iconic deep-sky objects. Glowing at 8th magnitude, it's ideally placed at its highest in the south these moonless evenings. It's on the border of Corvus and Virgo 10° west of Spica. Less well known are a bunch of nice telescopic double stars in the Sombrero's general area. Explore them all using Ken Hewitt-White's "Hat Hunt" article and finder charts in the May Sky & Telescope, page 55.

And in his Binocular Highlight column (same issue, page 43), Matt Wedel says M104 is "one of the few galaxies for which I can reliably detect an orientation in 10x50 binoculars." But for that you'll definitely need a very dark sky.

■ New Moon (exact at 11:22 p.m. EDT).

WEDNESDAY, MAY 8

■ The Arch of Spring spans the western sky in late twilight. Pollux and Castor form its top: They're lined up roughly horizontally in the west-northwest, about three finger-widths at arm's length apart. Look far to their lower left for Procyon, and farther to their lower right for 2nd-magnitude Menkalinan and then bright Capella.

On May 10th the waxing Moon will start stepping up through the inside of the Arch, as indicated below.

Waxing Moon in evening twilight, May 8-10, 2024
Back in the evening sky, the waxing crescent emerges to begin a new lunation. (The Moon is drawn three times its actual apparent size; it doesn't really overlap the Pleiades. Not that you will see the Pleiades so low in bright twilight anyway!)

THURSDAY, 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 low in the northeast as twilight fades.

Next up is Deneb, lower left of Vega by about two fists at arm's length. Deneb follows about an hour and a half behind Vega.

The third is Altair, which shows up far to their lower right by 10 or 11 p.m.

FRIDAY, MAY 10

■ 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. 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 from us, respectively.

This evening, Vega and Capella stand at the same height above the horizon shortly after dark.

SATURDAY, MAY 11

■ This is the time of year when Leo the Lion starts walking downward toward the west, on his way to departing into the sunset in early summer. Right after dark, spot the brightest star fairly high in the west-southwest. That's Regulus, his forefoot.

Regulus is also the bottom of the Sickle of Leo: a backward question mark about a fist and a half tall that outlines the lion's leading foot, chest, and mane.

SUNDAY, MAY 12

■ The thickening crescent Moon shines just left of Pollux this evening. About twice as far to their right, Castor lies nearly on the same line. For skywatchers in the Central time zone, the lineup is perfect about an hour after full dark. That happens later at night for the Eastern time zone, earlier if you're west of Central.


This Week's Planet Roundup

All seven planets other than Earth are crowding near our line of sight to the Sun. So this is the briefest "This Week's Planet Roundup" I ever remember!

Mercury, Venus, and Neptune are hidden in the glare of sunrise.

Mars and Saturn, both about magnitude +1.2, rise around the beginning of dawn. Look low above the east-southeast horizon about 60 minutes before sunrise. Saturn is the easier one. Mars is off to Saturn's lower left. They widen from 16° apart on the morning of May 4th (about a fist and a half at arm's length) to 21° on May 11th.

Jupiter and Uranus are hidden in the glare of sunset.


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 and graphics that also depend on longitude (mainly Moon positions) are for North America.

Eastern Daylight Time (EDT) is Universal Time minus 4 hours. UT is also known as UTC, GMT, or Z time.


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 a more detailed constellation guide covering the whole evening sky, use the big monthly map in the center of each issue of Sky & Telescope, the essential magazine of astronomy.

Once you get a telescope, to put it to good use you'll need a much more 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 all stars to magnitude 7.6.

Pocket Sky Atlas cover, Jumbo edition
The Pocket Sky Atlas plots 30,796 stars to magnitude 7.6, and hundreds of telescopic galaxies, star clusters, and nebulae among them. Shown here is the Jumbo Edition, which is in hard covers and enlarged for easier reading outdoors by red flashlight. Sample charts. More about the current editions.

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) or Uranometria 2000.0 (stars to mag 9.75). And read How to Use a Star Chart with a Telescope. It applies just as much to charts on your phone or tablet as to charts on paper.

You'll also want a good deep-sky guidebook. A beloved old classic is the three-volume Burnham's Celestial Handbook. An impressive more modern one is the big Night Sky Observer's Guide set (2+ volumes) by Kepple and Sanner.

Can computerized telescopes replace charts? Not for beginners I don't think (and not for anyone on mounts and tripods that are less than top-quality mechanically, meaning heavy and expensive). Unless, that is, you prefer spending your time getting finicky technology to work rather than learning the sky. 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."

If you do get a computerized scope, make sure the drives can be disengaged so you can swing it around and point it readily by hand when you want to, rather than only slowly by the electric motors (which eat batteries).

However, finding faint telescopic objects the old-fashioned way with charts isn't simple either. Learn the tricks at How to Use a Star Chart with a Telescope


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



"The dangers of not thinking clearly are much greater now than ever before. It's not that there's something new in our way of thinking, it's that credulous and confused thinking can be much more lethal in ways it was never before."
            — Carl Sagan, 1996

"Facts are stubborn things."
             John Adams, 1770


Comments


Image of mary beth

mary beth

May 8, 2024 at 11:55 am

“Robert H. Baker may have been the first to name the Great Diamond, in his 1954 book When the Stars Come Out.

When you posted this last year I bought the book and I couldn’t be happier with it. I found a pristine copy on eBay. I figured if it was mentioned here, it must be a very good book and it truly is. Thank you, Mr. MacRobert!

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Tony

May 9, 2024 at 12:46 am

Despite veils of high cloud and haze, the gossamer-thin, almost broken-looking Moon (a little less than 25 hours past New) was easy to see with 16x50 binoculars near my southern Vancouver Island home. I also found Sirius with little trouble less than 20 minutes after sunset, but haze was pesky for other stars even at 30 minutes.

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misha17

May 9, 2024 at 1:39 am

Re: Dusk sky chart, May 8-10:
"The Moon is drawn three times its actual apparent size; it doesn't really overlap the Pleiades. Not that you will see the Pleiades so low in bright twilight anyway"

Actually the Moon did pass through the Pleaides as seen from the tropics, as the Pleiades occultation series continues. However, as noted in the caption, even where it was visible it would have been difficult to see the cluster in the bright evening twilight.

The June occultation will also be difficult to see in the predawn twilight, but the July event will be easier to see, and by then a good portion the occultation path will north of the Equator, passing over the Pacific southeast of Japan (although the occultation will occur during the daytime along that part of its path).

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Image of Tony

Tony

May 9, 2024 at 1:24 pm

Jupiter and Venus are now visible on opposite sides of the occulted Sun in the Coronal Mass Ejections monitor at the NOAA/NWS Space Weather Prediction Center site.

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Image of misha17

misha17

May 9, 2024 at 3:57 pm

If you have your eclipse viewing glasses handy, you can use them for the next few days to view a very large sunspot.

More info here:
https://www.accuweather.com/en/space-news/still-have-eclipse-glasses-see-the-sunspot-15-times-wider-than-earth/1649162

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