This Week's Sky at a Glance, August 28 – September 6

FRIDAY, AUGUST 28 ■ As summer moves along and Arcturus moves down the western sky, the kite figure of Boötes that sprouts from Arcturus tilts to the right. The kite is narrow, slightly bent, and 23° long: about two fists at arm's length. Arcturus is its bottom point where the stubby tail is tied on. The Big Dipper poses to the right of it in the northwest at about the same height as Arcturus, as shown below. Look west-northwest these evenings for the Boötes Kite asterism leaning toward the Big Dipper. The fainter purple lines outline H. A. Rey's classic rendering of the whole Cowherd. He's seen in profile, sitting and smoking a pipe. Stars by Starry Night Pro 8. SATURDAY, AUGUST 29 ■ A winter preview: Step out before the first light of dawn any time this coming week, and the sky displays the same starry panorama that it will at dinnertime around New Year's. Orion will be striding up in the southeast, with Aldebaran and then the Pleiades high above it. Sirius sparkles far down below Orion. The Gemini twins are lying on their sides well up in the east. Even Saturn, slow mover among planets, will be located almost the same then as it is in pre-dawn now: under the Great Square of Pegasus high in the south-southwest. SUNDAY, AUGUST 30 ■ The waning gibbous Moon rises in the east in late twilight. Saturn follows it up about 30 minutes later. Another hour and they're nicely high free and clear. Although they look close together (about 5°), Saturn is currently 3,400 times farther away — and it's 35 times bigger in diameter than the Moon, not even counting the rings. And that dot is 9 times larger than the whole Earth. Nowhere in human experience but astronomy are things so different than they appear. It took millennia to figure that out; you are lucky. MONDAY, AUGUST 31 ■ The end of August means that Scorpius, which was the proud starring constellation in the south on July evenings, is now tilting over and lying down in the southwest after dark, preparing to bed down and drift off for the season. TUESDAY, SEPTEMBER 1 ■ Venus and Spica are in conjunction at dusk, as shown below. Venus will be getting very low in the west-southwest as twilight fades. Can you make out tiny Spica 1.5° above it? Spica is only 1/160 as bright! And they get lower by the minute. Bring binoculars. The Venus-Spica conjunction. Think photo opportunity, but getting a good image of Spica through the bright twilight will be tricky. Take various exposures, and don't be afraid to image-process the results — gently, of course. WEDNESDAY, SEPTEMBER 2 ■ Now Spica and Venus are 1.7° apart, with Spica to Venus's upper right. If it was cloudy last night, try again for a good image now. THURSDAY, SEPTEMBER 3 ■ Last quarter Moon tonight (exactly last-quarter at 3:51 a.m. Friday morning EDT ). The Moon will rise around 11 p.m. daylight-saving time, making this one of the earliest-to-rise last quarter Moons of the year. Watch for it to come up in the east-northeast almost two fists lower right of Capella. By the first glimmer of dawn Friday morning the Moon will be shining very high, between the Pleiades to its upper right and Beta Tauri closer to its lower left. FRIDAY, SEPTEMBER 4 ■ Venus and Spica are three days past their conjunction, 2.5° apart now as shown below. Bring binoculars. They're getting lower in twilight by the day. Venus and Spica widening. ■ Altair is that bright star high towards the south soon after dark. Find little Sagitta, the Arrow, barely a fist at arm's length above it as shown below. If your light pollution is too heavy, try binoculars. Now imagine rotating the Arrow on its point a third of a turn counterclockwise. Its middle star would now rest almost at M27, the Dumbbell Nebula. Finder chart for M27, the Dumbbell or Applecore Nebula, starting from Altair and then Sagitta. Tiny, dim M27 appears slightly purple here. It's just south of the middle star of an M-shaped asterism 3.8° wide. (The M's stars are magnitudes 4½ to 5½.) This frame is 16° wide, and north is very slightly left of up.Most deep-sky telescopic objects, like this one, are much tinier and fainter compared to their surroundings than new observers often expect. Stars by Starry Night Pro 8 With a total magnitude of 7½, the Dumbbell is a big but subtle gray glow to the human eye, nearly 0.1° wide. It's easy in binoculars or a finderscope through a good, dark, rural sky. In a 4- to 8-inch telescope it's visibly a rectangle or hourglass. It's the brightest planetary nebula in the sky if you sum up all of its spread-out light. The name Dumbbell Nebula was bestowed by John Herschel in 1828. He was referring to the exercise weights we still call dumbbells, but in his day they were sometimes made by connecting two heavy bells top-to-top by a short pipe. The bells were missing their clappers, so they were literally dumb bells. I saw examples once in a vintage photo of a gym. They really did look like the nebula's hourglass shape. A more recent name for M27, more realistic to modern eyes, is the Applecore Nebula. The earliest use of this name that I find using Google Books is from 1997. The Dumbbell Nebula, M27. This view is 0.9° wide, about the width of a typical 60-power eyepiece view in a telescope. North is up, east is left. The star 14 Vulpeculae (the middle of the "M") is magnitude 5.6. HD 189733, magnitude 7.7, is a yellow-orange K dwarf 63 light-years away from us, notable for having one of the first exoplanets discovered (a hot Jupiter). The nebula is far in the background, about 1,360 light-years away. SATURDAY, SEPTEMBER 5 ■ Look for bright Vega passing the zenith as twilight fades away, if you live in the world's mid-northern latitudes. Vega goes right through your zenith if you're at latitude 39° north (near Baltimore, Kansas City, Lake Tahoe, Sendai, Beijing, Ankara, Athens, Lisbon). Almost exactly two hours later, Deneb crosses closest to the zenith. 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. SUNDAY, SEPTEMBER 6 ■ With the evening sky moonless, this is a great week for the Milky Way under a dark sky. When Deneb crosses your zenith (around 10 or 11 p.m. now), the Milky Way does too — running straight up from the southwest horizon and straight down to the northeast horizon. This Week's Planet Roundup Mercury is out of sight deep in the sunset. Venus continues to shine brightly (magnitude –4.5) as the "Evening Star" low in the west in twilight, lower every week now. It sets shortly before the end of twilight. Venus is passing fainter Spica. On Friday the 28th they're 3½° apart, with Spica to Venus's upper right. Their conjunction comes the next day, September 1st, when Spica will be 1½° above Venus and perhaps a bit right. After that Spica moves farther off to Venus's right as they both sink. In a telescope Venus is a thick crescent 28 arcseconds from pole to pole. Catch it as soon in late afternoon or early dusk as you can, before it sinks low into poorer seeing. Venus will remain in twilight view until the end of the summer, lower and lower while it enlarges and wanes in phase. Mars (magnitude +1.3, in the middle of Gemini) still rises around 2 a.m. daylight-saving time. By the beginning of dawn you'll find it glowing high in the east to the right of Pollux and Castor. Since Mars is on the far side of its orbit from us, in a telescope it's still a tiny, fuzzy blob just 5 arcseconds wide. Jupiter (magnitude –1.8, in dim Cancer) rises nearly an hour before twilight begins. As dawn brightens, look for it glowing steadily low in the east-northeast. Saturn (magnitude +0.5, at the Pisces-Cetus border) rises in the east around the end of twilight. Look for it about a fist and a half below the Great Square of Pegasus (which is balancing on one corner). Saturn is best placed for telescopic viewing high toward the south in the early-morning hours. It transits around 3 a.m. On July 25th, planetary imager Christopher Go caught Saturn's rings displaying unusually prominent, obvious ring spokes. They're the gray streaks near the left (celestial east) end of the broad B ring. (North here is up, east is left.)A few telescopic reports of these subtle, transient features date from the 19th century. The first systematic study of them was done by Sky & Telescope's Stephen James O'Meara, a famously eagle-eyed visual observer, using Harvard Observatory's 9-inch Clark refractor starting in 1977. Spacecraft flybys later confirmed them in detail.The spokes remain something of a mystery. Says Wikipedia, "The leading hypothesis... is that they consist of microscopic dust particles suspended away from the main ring by electrostatic repulsion, [because] they rotate almost synchronously with the magnetosphere of Saturn," not with the ring material itself Electrons in the solar wind, as redirected by Saturn's magnetic field, may be involved. "The precise mechanism generating the spokes is still unknown." Uranus (magnitude 5.7, in Taurus) lurks halfway between the Pleiades and Aldebaran in the early morning sky. Neptune (magnitude 7.8, at the Pisces/Cetus border) lurks even deeper 10° west of Saturn. You'll need detailed finder charts to tell Uranus and Neptune from stars of similar brightnesses. 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