THURSDAY, JULY 4

■ Spot the Big Dipper high in the northwest at nightfall, and lower later. It turns around as night advances to "scoop up water" — a half hour earlier every week.

FRIDAY, JULY 5

■ The largest asteroid, 1 Ceres, is at opposition in the handle of the Sagittarius Teapot. At magnitude 7.3 it's in binocular range. Use the finder chart in the July Sky & Telescope, page 48. (The ticks on its track there mark its position at 0:00 UT on the dates indicated, which for the Americas falls on the afternoon or evening of the previous date.)

From now through July 12th, Ceres is less than 1° from the bottom star of the Teapot's handle. On the night of July 14th, Ceres will be 0.6° north of the little 8th-magnitude globular cluster M54.

■ Earth is at aphelion today, its farthest from the Sun for the year, just 3.3% farther than at perihelion in January.

■ New Moon, exactly so at 6:57 p.m. EDT (22:57 UT).

SATURDAY, JULY 6

■ This evening about 20 or 30 minutes after sunset, try to sight the extremely thin young crescent Moon low in the west-northwest, as shown below. Will this be your record youngest Moon? For most of North America, you're seeing it only 25 to 28 hours old depending on where you are. To find the Moon's age, compare the time of your sighting with the time of new Moon above.

Crescent Moon, Mercury, and Venus just above the WNW horizon in bright twilight, July 6, 2024
Barely more than 24 hours after new, the Moon is an extremely thin waxing crescent very low after sunset accompanying Mercury. And maybe Venus. Use binoculars.

SUNDAY, JULY 7

■ The two-day-old crescent Moon now hangs over Mercury in bright twilight, more or less as shown below. Try for Venus too, which is still way down farther to Mercury's lower right. Good luck.

The crescent Moon hangs over Mercury July 7th, then Regulus July 9th (2024).
After passing Mercury in twilight, the thickening crescent passes Regulus.

MONDAY, JULY 8

■ Hercules crosses the zenith these evenings. And in the western edge of the Hercules Keystone, how many times have you pointed a scope at old friend M13, the great globular cluster? You do that not just because it's one of the finest globulars in the sky, but because it's easy to find.

And because we fall into habits.

So the other grand globular of Hercules, M92 just 9° away, goes way overlooked. The two seem like, if not twins, close siblings. M92 is nearly as large and nearly as bright as M13, but it's off in the wilds north of the Keystone.

And what about the ignored little kid of the Hercules globular family, NGC 6229? It's a few degrees farther north of the Keystone and only magnitude 9.4, but still within reach of smallish scopes. Where it definitely qualifies as a faint fuzzy. . .

. . .As Ken Hewitt-White calls it in his "Suburban Skygazer" article in the July Sky & Telescope, page 56. Use its big, detailed chart for finding all three. Not to mention three nice double stars right near M13 that you probably didn't know about.

That article is titled "Great Balls of Fire," but come on. I've always seen globulars as sugar piles in moonlight. Don't wait; the actual Moon will start lighting the evenings in a few days.

TUESDAY, JULY 9

■ Soon after nightfall, look due south for orange Antares on the meridian. Around and upper right of Antares are the other, whiter stars forming the distinctive pattern of upper Scorpius. The rest of the Scorpion runs down from Antares toward the horizon, then left.

Three doubles in the top of Scorpius. The "head of Scorpius" is the near-vertical row of three stars upper right of Antares. The top star of the row is Beta Scorpii or Graffias: a fine double star for telescopes, separation 13 arcseconds, magnitudes 2.8 and 5.0.

Just 1° below Beta is the fainter, very wide naked-eye pair Omega1 and Omega2 Scorpii, tilted to the right of vertical. They're 4th magnitude and ¼° apart. Binoculars show their slight color difference; they're spectral types B9 and G2.

Upper left of Beta by 1.6° is Nu Scorpii, separation 41 arcseconds, magnitudes 3.8 and 6.5. In fact this is a telescopic triple. High power in very good seeing reveals Nu's brighter component itself to be a close binary, separation 2 arcseconds, magnitudes 4.0 and 5.3, aligned almost north-south.

WEDNESDAY, JULY 10

■ To the right of Antares is that roughly vertical row of Beta, Delta, and fainter Pi Scorpii. The middle one, Delta Sco, is the brightest obviously so. But it didn't used to be. It used to be like Beta.

Antares, Delta Scorpii, and Head of Scorpius
The brightest star near Antares is Delta Scorpii, now in its 24th year of an unexpected flareup. Photographs don't show the brightness differences between stars well, but to the naked eye Delta is obviously the brightest star in the nearly vertical row of three forming the head of Scorpius. Outdoors at night, estimate Delta's magnitude by comparing it with Beta, magnitude 2.6, and Antares, 1.1.

Delta is a strange variable star, a fast-rotating blue subgiant throwing off luminous gas from its equator. Assumed for centuries to be stable, Delta doubled in brightness unexpectedly in the summer of 2000, then dipped down and up again several times from 2005 to 2010, and has remained essentially steady at peak brightness (magnitude 1.7) ever since. If anything, it has gained just under a tenth of a magnitude in these last 14 years.

Delta has a smaller orbiting companion star that was suspected to trigger activity in it at 10.5-year intervals. Astronomers predicted the system might have another flareup around 2022, when the companion star made its third pass by the primary since 2000. But nothing happened.

No one knows what might happen next, or when.

THURSDAY, JULY 11

■ As summer progresses, bright Arcturus moves down the western side of the evening sky. Its pale ginger-ale tint always helps identify it.

Arcturus forms the bottom point of the Kite of Boötes. The Kite, rather narrow, extends upper right from Arcturus by 23°, about two fists at arm's length. The lower right side of the kite is dented inward, as if some celestial intruder collided with it. The kite tilts toward the Big Dipper.

FRIDAY, JULY 12

■ The Moon, just short of first quarter, shines west of Spica this evening as shown below, creeping toward Spica to occult it tomorrow. Plan ahead for your occultation watch!

Moon passing Spica at dusk, July 12-14, 2024
The Moon steps smack across Spica this month as seen from North America. (These scenes are always drawn for an observer at latitude 40° N, longitude 90° W, near the population center of the continent. The Moon's position with respect to Spica will differ a bit depending on where you are. The Moon here is drawn about three times its actual apparent size.)

SATURDAY, JULY 13

The first-quarter Moon occults Spica this evening for virtually all of North and Central America. The 1st-magnitude star will vanish behind the Moon's dark limb, then will reappear from behind the bright limb up to an hour or more later. Rarely do we see the Moon occult such a bright star!

Paths of Spica behind the Moon during occultation 7-13-2024
Spica takes a different path behind the Moon depending upon your location. Five cities are shown here. Except for New York, NY and other cities in the Eastern Time Zone, both the disappearance and reappearance of Spica will be visible. Paths are approximate. Map by Bob King with Stellarium

For the East Coast the Moon will be getting low in the western sky (plan a good observing spot beforehand). For much of the West the Sun will still be up — but Spica will probably be visible through the blue sky in a telescope, just not so easily.

In a dark sky even your naked eyes might be enough to catch the disappearance, depending on your vision and the clarity of the air.

Map and timetables. The first two tables, with predictions for many cities, are long. The first gives the times of Spica's disappearance behind the Moon's dark limb; the second its reappearance out from behind the bright limb (less observable). Scroll to be sure you're using the correct table; watch for the new heading as you scroll down. The first two letters in each entry are the country abbreviation (CA is Canada, not California). The times are in UT (GMT) July 14. UT is 4 hours ahead of Eastern Daylight Time, 5 hours ahead of CDT, 6 ahead of MDT, and 7 ahead of PDT.

For instance: Use the first table to see that for Chicago, Spica disappears on the dark limb at 10:10 p.m. July 13th CDT, when the Moon is 19° high in the west-southwest (azimuth 234°). Spica reappears from behind the bright limb at 11:22 p.m. CDT, when the Moon is only 8° high.

For more info and pix: Catch an Exciting Spica Occultation on July 13th, by Bob King.

SUNDAY, JULY 14

■ The tail of Scorpius is at its best low due south soon after dark. It's about a fist and a half at arm's length lower left of Antares, and a fist or less lower right of the Sagittarius Teapot's spout. How low this scene appears depends on how far north or south you live: the farther south, the higher.

Look for the two stars especially close together in the tail. These are Lambda and fainter Upsilon Scorpii, known as the Cat's Eyes. They're canted at an angle; the cat has a bleary eye and is tilting his head to the right. Lambda is brighter than Upsilon; they're magnitudes 1.6 and 2.6. Both are blue-white supergiants, 700 and 500 light years away, respectively. Yes, the nearer one is the fainter one.

A line through the Cat's Eyes points west (right) by nearly a fist-width toward Mu Scorpii, a much tighter pair known as the Little Cat's Eyes. These are oriented almost exactly the same way as Lambda and Upsilon, but they're only 0.1° apart; use binoculars. They're not a true binary: they're 800 and 500 light-years away, respectively. And yes, the fainter one is the nearer of these also.


This Week's Planet Roundup

Mercury is not an easy catch even at magnitude –0.2. Look for it quite low in the west-northwest during bright evening twilight. Bring binoculars.

Venus is even deeper in evening twilight, about 13° to Mercury's lower right (roughly a fist at arm's length). Try about 20 minutes after sunset, and use those binoculars. At least Venus is bright: magnitude –3.9.

Mars (magnitude +0.9, in Aries nearing Taurus) glows modestly in the eastern sky before and during early dawn, upper right of bright Jupiter by 1½ or 2 fists. In a telescope Mars is just a tiny fuzzblob 5.5 arcseconds wide.

Jupiter (magnitude –2.0, in Taurus) glares low in the east-northeast before and during early dawn.

Saturn (magnitude 1.1, near the Aquarius-Pisces border) rises around midnight and shines high in the southeast before dawn. The Great Square of Pegasus is two fists upper left of it, and Fomalhaut sparkles two fists lower right of it.

Saturn with rings nearly edge-on, June 1, 2024
Saturn's rings are nearly edge-on this year. Note the stark black shadow they cast southward (upward here) onto the globe. Christopher Go took this image on June 1st.

Uranus, magnitude 5.8, is between Jupiter and Mars. But that's still low in the dawn for something so faint.

Neptune, magnitude 7.9 in Pisces, is about 10° left of Saturn before dawn begins if you have large binoculars or a telescope, a detailed finder chart showing Neptune's current location among the similar-looking faint stars around it, and skill in using sky charts with binocs or a scope.


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. (It's currently out of print.) The next up 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. The top of the hill for total astro-geeks is the Annals of the Deep Sky series, currently at 10 volumes as it slowly works forward through the constellations alphabetically. So far it's only up to F.

Can computerized telescopes replace charts? Not for beginners I don't think, and not for scopes on mounts and tripods that are less than top-quality mechanically. 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 and a curious mind." Without these, "the sky never becomes a friendly place."

If you do get a computerized scope, make sure its 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 essential 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 Tony

Tony

July 4, 2024 at 6:48 am

With help from 16x50 binoculars, I found Venus for the first time in this evening apparition on July 3, six minutes before official sunset, although the Sun was already behind Vancouver Island mountains. Some 40 minutes later Mercury was in easy view through the same binoculars; Pollux needed more effort but was a definite twinkler. At my 48º latitude, twilight stays bright for quite a while this time of year.

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Image of Dave-Kandz

Dave-Kandz

July 8, 2024 at 10:19 am

Managed to sight the 1500 minute old moon from the roof of a nearby parking garage - my current personal record!

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Image of misha17

misha17

July 10, 2024 at 2:28 pm

Worrisome news - an astronomer posted an article theorizing that Comet Tsuchinshan-ATLAS (C/2023 A3) may break up before perihelion.

Link to PDF document:
https://arxiv.org/abs/2407.06166

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