This Week's Sky at a Glance, July 31 – August 9

FRIDAY, JULY 31 ■ Bright Vega passes its closest to straight overhead around 11 p.m., depending on how far east or west you live in your time zone. How closely it misses your zenith depends on how far north or south you are. It passes right through your zenith if you're at latitude 39° north (Washington DC, Cincinnati, Kansas City, Lake Tahoe). How closely can you judge this just by looking? Deneb crosses closest to the zenith almost exactly two hours after Vega. But to see Deneb straight up you need to be farther north, close to latitude 45°: Portland, Minneapolis, Montreal, central Maine, southern France, northern Italy, Odesa, Kherson. SATURDAY, AUGUST 1 ■ Today is Lammas Day or Lughnasadh, one of the four traditional "cross-quarter" days midway between the solstices and the equinoxes. Sort of. In the many centuries after this tradition arose in Europe and the British Isles, the calendar drifted with respect to Earth's position in orbit (until our Gregorian calendar was instituted a few centuries ago to deal with such problems). So in 2026, the midpoint between the June solstice and the September equinox actually falls on the night of August 6-7: at 12:13 a.m. Eastern Daylight Time (9:13 p.m. Pacific Daylight Time). That minute is the exact center of astronomical summer: the very top of the circle of the year as defined by the astronomical seasons (for the Northern Hemisphere; the cold bottom of the year for the Southern Hemisphere.) SUNDAY, AUGUST 2 ■ Enormous Ophiuchus, the Serpent-Holder, stands atop Scorpius in the south-southwest after dark, butting heads with Hercules higher up. The brightest star of Ophiuchus is Rasalhague ("Head of the Snake Collector"). It's easily spotted west of the big Summer Triangle as shown below. (The Summer Triangle is now very high in the east, with Vega nearly overhead.) The brightest star of Ophiuchus is Rasalhague. Find it from the big Summer Triangle. Bob King Right near Rasalhague is the head of Hercules: Alpha Herculis, Rasalgethi, "Head of the Kneeler." In the photo above, it's the little unlabeled dot just above the third "a" in Rasalhague. It's a somewhat variable orange-red giant that's usually about magnitude 3.3. Rasalgethi is a fine summer double star for amateur telescopes. The secondary star is magnitude 5.3 and pale yellowish. They're 4.6 arcseconds apart, so use maybe 150x or 200x. It's a bit unusual for both components of a bright binary star to be on the yellow/orange side of white. ■ Moving on: South of Rasalhague by 8°, find Ophiuchus's east shoulder: Beta Ophiuchi, Cebalrai. It's 3rd manitude. Eight degrees east of this is a dim V-shaped asterism like a smaller, fainter version of the Hyades in Taurus. This is the face of the defunct constellation Taurus Poniatovii, "Poniatowski's Bull." The V is 2½° tall. It stands almost vertically right after nightfall now. 1 The V-shaped face of Poniatowski's little Bull lurks 5° east of Ophiuchus's eastern shoulder, Cebalrai. Just 1¼° north-northeast of Cebalrai, the loose open cluster IC 4665 waits to flirt with visibility in your binoculars. This field is 15° wide, and north is to the upper right.To find your way, start from the brightest star here, 2nd-magnitude Rasalhague, findable from the Summer Triangle as shown on the photo earlier above. Cebalrai is 8° south of Rasalhague. Starry Night Pro 8 The top two stars of the V are the faintest (magnitudes 4.8 and 5.5). The middle star of its east side is the famous K-dwarf binary 70 Ophiuchi, visual magnitudes 4.2 and 6.2, distance just 17 light-years (the same as Altair). The two stars of the pair are currently 6.7 arcseconds apart in their 88-year orbit: close but nicely separated at medium-high power in any telescope. Just 1¼° NNE of Cebalrai is the large, very loose open cluster IC 4665, a binocular target 1,100 light-years away. That's relatively near for an open cluster, which accounts for its rather loose, large apparent size; it's a little more than ½° across. If you orient your view so celestial SSW is up — in other words putting Cebalrai straight above the cluster — its central stars spell out a ragged but more-or-less legible welcome: "HI". IC 4665 is happy to see you. South-southwest is up. Wikimedia Commons The "HI" will be in mirror writing if your view is mirror-reversed. That happens whenever your optical system has an odd number of reflections, such as if you use a star diagonal at the eyepiece. For more telescopic sights in this area, including Barnard's Star, doubles in IC 4665, and two other clusters, see Ken Hewitt-White's "Suburban Stargazer" section in the July 2025 Sky & Telescope, page 55. (The text there misidentifies Collinder 350 as "359".) MONDAY, AUGUST 3 ■ Seen any Perseid meteors yet? The peak night for this famous annual shower should be the night of August 12-13 this year: a week from Wednesday. But the occasional Perseid may begin to show up by the beginning of August. If you see a shooting star now, trace its path far backward across the sky. If you cross the location of the Perseid radiant, between Perseus and Cassiopeia in the northeast, you almost surely saw an early Perseid. The shower builds slowly for about two weeks, then drops off more rapidly after its peak. TUESDAY, AUGUST 4 ■ The brightest star high in the southeast these evenings is 1st-magnitude Altair, with little orange Tarazed above it by a finger-width at arm's length. A little more than a fist-width to Altair's left is delicate Delphinus, the Dolphin. He's leaping leftward. Above or upper left of Altair, by slightly less far, is smaller, fainter Sagitta, the Arrow. It too points leftward. You'll need a dark sky to see these two constellations naked-eye. But even if your sky is too light-polluted, binoculars will likely show each. Altair, the eagle eye of Aquila, with two of Aquila's little companion constellations. (Two others, blander Vulpecula and Equuleus, are offscreen to the top and lower left, respectively.) You'll definitely need binoculars for the distinctive little Coathanger asterism, also known as Brocchi's Object. North is up. Stars by Starry Night Pro 8 WEDNESDAY, AUGUST 5 More Aquila. One of the brightest Cepheid variable stars in the sky — a naked-eye, glance-up-to-check-it variable star just waiting there for you — is Eta Aquilae, high on display these evenings. Never heard of it? It's 8° south of Altair and pulses from magnitude 4.3 to 3.4 and back every 7.18 days. That's slightly more than a doubling of brightness, then a halving of brightness. As with other classical Cepheids its rise to maximum is faster than its fade to minimum. Its period is so close to a week that you'll find it repeating itself on the same weekdays for a month or two at a time. Judge its brightness by comparing it between Theta Aquilae, magnitude 3.2; Delta Aql, mag. 3.4; Beta Aql, mag. 3.7; and Iota Aql, mag. 4.4. These are marked in blue on the chart below. They're all part of Aquila's flying-eagle stick figure. Altair is the eagle's bright eye. The Cepheid variable star Eta Aquilae is surrounded by four nice naked-eye comparison stars. Their visual magnitudes are labeled. ■ Last-quarter Moon tonight (exactly so at 10:21 p.m. EDT). The Moon rises in the east-northeast around 11 or midnight tonight, when the terminator will look perfectly straight (for the Americas). By the beginning of dawn Thursday morning the Moon will be very high in the southeast, with the Pleiades about a fist to its left or lower left. THURSDAY, AUGUST 6 ■ The Moon occults some of the Pleiades late tonight for observers in eastern North America. Elsewhere, the Moon will closely accompany the Pleiades. The Moon will rise around midnight local daylight-saving time. Because the Moon is waning, its bright limb will be the side that occults stars, ruling out binoculars for seeing these events. But with a telescope at high power you may be able to follow the brighter stars right up to the Moon's dazzling edge to see them wink out. They'll reappear from behind the Moon's dark limb up to an hour or more later, events much easier to see — if you're watching right at the exact moment! To get time predictions for your location, open an accurate planetarium program set for your location and the date, run the time back and forth, and write down the times of events to watch for in real life. FRIDAY, AUGUST 7 ■ Venus, the "Evening Star," continues to hang in there low in the western twilight. Spica, 1st-magnitude but less than 1% as bright even so, is closing in on Venus from the upper left as shown below. Tonight they're still 23° apart (about two fists at arm's length). Watch Spica creep toward Venus until their conjunction on September 1st, when they'll pass 1.4° apart even lower after sunset. ■ The two brightest stars of summer are Vega, overhead shortly after nightfall, and Arcturus, shining in the west. Draw a line down from Vega to Arcturus. A third of the way down, the line crosses the dim Keystone of Hercules. Two thirds of the way down it crosses the dim semicircle of Corona Borealis with its one modestly bright star, 2nd-magnitude Alphecca or Gemma. Vega and the Keystone's star closest to it form an equilateral triangle with 2nd-magnitude Eltanin to their north, the nose of Draco the Dragon. Eltanin is the brightest star of Draco's quadrilateral head; he's eyeing Vega. SATURDAY, AUGUST 8 East of Cygnus, the Milky Way runs between Cepheus and faint little Lacerta, the Lizard, before reaching Cassiopeia. Although the Lizard's stick figure is made of only 4th and 5th-magnttude stars, it's rich with Milky Way background swarms. Including the open star cluster NGC 7209. With a total magnitude of 6.7, this cluster is within reach of largish binoculars on dark nights like we have this week. "The cluster is a pretty, mottled haze in my 10x50s," writes Matt Wedel in his Binocular Highlight column (with chart) in the August Sky & Telescope, page 43. "At 3,800 light-years it's pretty far out there for an open cluster one might study with binoculars. " ■ On Sunday morning before and during early dawn, the waning crescent Moon shines near Mars and the horntips of Taurus. Look east. SUNDAY, AUGUST 9 ■ The Big Dipper hangs diagonally in the northwest after dark, as shown below. From its midpoint, look to the right to find Polaris (not very bright) glimmering due north as always. The Dippers as they're positioned after dark at this time of year. If you can see the whole Little Dipper you have a darker sky than most of us. But 2nd-magnitude Polaris and Kochab are in much easier view, and 3rd-magnitude Pherkad is not far behind. It's a wide optical double in binoculars. Akira Fujii photo Polaris is the end of the Little Dipper's handle. The only other Little Dipper stars that are even moderately bright are the two forming the outer end of its bowl: 2nd-magnitude Kochab and 3rd-magnitude Pherkad. On August evenings you'll find them to Polaris's upper left (by about a fist and a half). They're called the Guardians of the Pole, since they ceaselessly circle around Polaris through the night and through the year. I sometimes imagine them marching around and around like the Wicked Witch's guards in the Wizard of Oz movie, chanting "O-ee-o, Eeee-o." They do not in fact do this. They are giant, orange-hot and white-hot balls of gas, respectively, spectral types K4 III and A2 III, located 131 and 490 light-years away. They neither march nor speak. Nevertheless, imaginative conceptions and artistic impressions are real things: abstract things that exist in the few cubic inches of your skull, physically encoded in part of the neural network that gives rise to your mind. External realities and your internal experiences of them are thus both real things, but they are truly fundamentally separate orders of being. Confusing the two with each other is, the more you examine it, the origin of a very large slice of humanity's many failings and delusions. ■ Get ready for the solar eclipse coming next Wednesday August 12th (the day of peak Perseid night!). The eclipse will be total only for parts of Greenland, Iceland, and (near sunset) northern Spain, and for a long strip of the Atlantic Ocean. But a partial eclipse will occur for much of the US and all of Canada. The southern limit of the partial eclipse runs from near Vancouver past the south tip of Lake Michigan and on to the North Carolina coast. More details. To get your local timetable of the eclipse's events for any location, zoom in and click on this map. This Week's Planet Roundup Mercury is visible low in the dawn this week. Look for it above the east-northeast horizon about 40 or 50 minutes before sunrise. It's brightening daily: from magnitude +0.3 on Saturday morning August 1st to –0.6 on Saturday morning the 8th. That's more than a doubling of brightness. Don't confuse Mercury with fainter Pollux and Castor somewhat higher to its upper left. Venus continues to shine brightly (at magnitude –4.3) as the "Evening Star" low in the west in twilight. It continues to set around twilight's end. In a telescope, Venus is a brilliant, half-lit disk 21 arcseconds from pole to pole. Catch it as soon in late afternoon or early dusk as you can, before it sinks low into poorer atmospheric seeing. Venus will remain in twilight view until the end of the summer, gradually lower, enlarging while waning in phase. Mars (magnitude +1.3, in Taurus) glows in the east before and during early dawn. Aldebaran, its near-twin for brightness and color, twinkles to its upper right by about a fist and a half. This week Mars passes between the horntip stars of Taurus. Mars is still on the far side of its orbit from us. So in a telescope it's only a tiny, fuzzy blob 5 arcseconds wide. Jupiter is buried deep in the glow of dawn. Saturn (magnitude +0.6, at the Pisces-Cetus border) rises in the east around 11 pm. Once it's up find it below the Great Square of Pegasus, which is balanced on one corner. Saturn is best placed for telescopic viewing high in the southeast before the first light of dawn. The waning Moon poses with it on the mornings of August 3rd and 4th. Late last fall Saturn's rings turned nearly edge-on to Earth and almost disappeared. Now the rings' inclination has widened back up to 9°. Saturn on July 3rd, imaged by Christopher Go. North is up. "Conditions were perfect today," Go writes. "Saturn's rings are opening up, and the Encke [Gap] is very well resolved." That's the thin black hairline barely inside the rings' outer edge, much thinner than the prominent black Cassini Division closer in. Both are best visible near the rings' ansae, their narrow ends. The planet casts its shadow lower right here onto the rings. Uranus (magnitude 5.7, in Taurus) hides in the background about 20° west of Mars along the ecliptic. Neptune (magnitude 7.8, at the Pisces/Cetus border) hides even farther in the background 10° west of Saturn. You'll need detailed finder charts to tell Uranus and Neptune from stars of similar brightness. 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. For the attitude every amateur astronomer needs, read Jennifer Willis's Modest Expectations Give Rise to Delight. Once you get a telescope, to put it to good use you'll want 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. Both show all 30,000 stars to magnitude 7.6, and 1,500 deep-sky targets — star clusters, nebulae, and galaxies — to search out among them. The Pocket Sky Atlas plots 30,796 stars to magnitude 7.6, and 1,500 telescopic galaxies, star clusters, and nebulae among them. Shown here is the Jumbo Edition, which is in hard covers and enlarged for easier reading in the dark 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, as well as many more deep-sky objects. It's currently out of print, but maybe you can find one used. The next up, once you know your way around well, are the even larger Interstellarum Deep-Sky Atlas (with 201,000+ stars to magnitude 9.5 and 14,000 deep-sky objects selected to be detectable by eye in very large amateur telescopes), and Uranometria 2000.0 (332,000 stars to mag 9.75, and 10,300 deep-sky objects). For the necessary tricks, read How to Use a Star Chart with a Telescope. It applies just as much to electronic charts on your phone or tablet — which many observers find handier and more versatile, if sometimes less well designed and contextualized. You'll also want a good deep-sky guidebook. A beloved old classic is the three-volume Burnham's Celestial Handbook. It was my bedside reading for years. An impressive more modern one is the big Night Sky Observer's Guide set (2+ volumes) by Kepple and Sanner. The pinnacle for total astro-geeks is the new Annals of the Deep Sky series, currently at 11 volumes as it works its way forward through the constellations alphabetically. So far it's up to H. Can computerized telescopes replace charts? Well, I used to say this: "Not for beginners, I don't think, unless you prefer spending your time getting finicky technology to work rather than learning how to explore through the sky yourself. 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.' " But things change. The technology has continued to improve and become more user-friendly — particularly with "plate solving" software that can now recognize any star field to determine exactly where the telescope is pointed — finally bypassing all aiming imperfections in the mount, tripod, gears, bearings and other mechanics, or in the user's skill in setting up. The latest revolution is the rise of small, photography-only "smartscopes." These take advantage of not only today's pointing technology, but also the vastly better capabilities of imaging chips and image processing compared to the human retina and visual cortex. The most sophisticated image stacking and processing can come built right in. The result is decent deep-sky imaging from shockingly small units, relatively low priced. The image may be viewable on your phone or computer as it builds up in real time. Some can directly enable contributions to citizen-science projects. Smartscopes are changing the hobby at the entry level. For more on this see Richard Wright's "The Rise of the Smart Telescopes" in the November 2025 Sky & Telescope. And read the magazine's review of this especially small one. If you get a larger, more conventional computerized scope that you can look through, make sure that 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). Audio sky tour. Out under the evening sky with yourearbuds in place, listen to Kelly Beatty's monthlypodcast 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, The Demon-Haunted World: Science as a Candle in the Dark "Facts are stubborn things; and whatever may be our wishes, our inclinations, or the dictates of our passion, they cannot alter the state of facts and evidence." — John Adams, 1770, in the summation of his unpopular, but successful, defense of British soldiers in the Boston Massacre trial "Truly, whoever can make you believe absurdities can make you commit atrocities." — Voltaire, 1765, Questions sur les miracles 1. Taurus Poniatovii was invented by the rector of Vilnius University, Marcin Poczobut, in 1773 to flatter his ruler Stanislaus Poniatowski, King of Poland and Grand Duke of Lithuania. The Poniatowski family's coat of arms displayed a bull. Poczobut may have needed money for the university; scholars in those days often had to obsequiously, embarrassingly, flatter up their monarchs and oligarchs for funding.2 Recently, echoes of this old requirement have returned in the United States. The V asterism in Poniatowski's Bull was meant to echo the real Taurus's face formed by Aldebaran and the brightest Hyades. The rest of the little bull trailed off to the northeast. A few star mappers included it on their sky charts for a while, since Poczobut was respected as an astronomer (J.-J. de Lalande used some of his fine positional measurements to help calculate the orbit of Mercury. But the bull on his king's coat of arms has long since dropped from the sky. Nevertheless, today "a depiction of the constellation can be found on the wall of the Vilnius University Astronomical Observatory" per Wikipedia. I can't find a photo of that online. Today Vilnius University thrives in a free Lithuania. Can somebody there go look through the observatory? If you find Taurus Poniatovii on the wall where it was born, please send me pics: [email protected]. 2. For instance, see the elaborate title pages by Galileo fawning over the Medicis and by Kepler buttering up his "Roman" Emperor Rudolph II. William Herschel, originally from what is now Germany, named his new planet (now Uranus) "The Georgian Star" to magnify his financial patron, England's King George III. Herschel's 1781 letter to the Royal Society announcing this name (and using the long s ) drips with flattery: Excerpt from Herschel's letter, read in the Royal Society on November 7, 1781, announcing his naming the new planet Georgium Sidus, "the Georgian Star." Published in the Philosophical Transactions of the Royal Society in early 1782. "Georgium Sidus" went over very badly outside England. French astronomers called the planet Herschel, following the lead of Charles Messier. Others proposed Astraea, Cybele, Minerva, and more names. After bitter international debates, astronomers beyond England eventually settled on Uranus — a variant on the Greek deity considered the father of Saturn, just as Saturn was the father of Jupiter. But the English shunned the name Uranus for nearly 70 more years. All well and good. But "Uranus" was actually proposed by the German astronomer Johann Elert Bode only four months after Herschel named the planet for his funder. I've wondered if Bode may have had a covert second purpose for the name (its last four letters mean the same in Latin and English) as a low joke for "you're [a] kiss-ass": a term for "obnoxious sycophant" that was already in use at the time in both English and German. Johann Elert Bode (1747 – 1826) as portrayed circa 1802 with a slightly upturned eyebrow and a subtle grin. I've never seen a trace of evidence for this notion, other than the name being the butt of jokes for well over a century. (Albert Stern has attempted to find the first recorded Uranus joke. The earliest clear one he found is from 1881, and he turned up possibles from the 1870s and 1852. And he was only looking in U.S. publications.) Elsewhere we read that "Exactly why Bode proposed the Latinized name Uranus over the Greek name for the god of the sky (Ouranus) is unclear. Also, it’s unclear why Bode did not use the Roman name for the god, Caelus, in keeping the with the Roman names of the other planets," including Saturn and Jupiter. Could Bode have been subtly satirizing his emigré former countryman for sucking up so blatantly to the English king?