This Week's Sky at a Glance, August 2 – 11

FRIDAY, AUGUST 2

■ Week by week, Venus is getting just a bit higher in the sunset. Using optical aid, can you pick it up a bit to the right of due west? And then detect Regulus and Mercury to its left, as indicated below? This could be your last day for those last two; they're sinking fast.

SATURDAY, AUGUST 3

■ Bright Vega passes closest to overhead around 10 or 11 p.m., depending on how far east or west you live in your time zone.

How closely Vega 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 two hours after Vega. But to see Deneb exactly straight up you need to be farther north, at latitude 45°: Portland, Minneapolis, Montreal, central Maine, southern France, northern Italy, Odesa, Kherson.

SUNDAY, AUGUST 4

■ New Moon (exact at 7:13 a.m. on this date EDT).

■ The T Cor Bor Watch continues. Have you been checking Corona Borealis overhead these clear evenings? The recurrent nova T Coronae Borealis could erupt to 2nd magnitude anytime this summer. Or fall. Or later? Astronomers are pretty sure it's preparing to blow sometime fairly soon for the first time since 1946.

What's the exact spot to watch?

Look a third of the way from Arcturus to Vega. There's Alpha Coronae Borealis, also known as Alphecca. At magnitude 2.2 it's the only moderately bright star in the delicate Northern Crown. Alphecca is easy to see through my suburban light pollution. The rest of Corona Borealis is not.

Is Alphecca alone? One of these days, it won't be!

In 1866 and 1946 T Cor Bor peaked at 2nd or 3rd magnitude, roughly matching Alphecca. See Bob King's Is the Blaze Star About to Blow? You May Be the First to Know, with more information and detailed charts.

Even now, as it simmers along near its normal 10th magnitude, T CrB is a pretty easy pickup using Bob's charts with a small telescope. Give it a look while it's still gathering its forces.

T Cor Bor's rise last time took just a few hours, and its peak brightness lasted only a day or so. To sign up for the fastest alert from the AAVSO or The Astronomer's Telegram, see the end of Bob's article linked above.

But for your best chance of catching it early, just look. Every night you can.

MONDAY, AUGUST 5

■ A hairline-thin crescent Moon, less than two days old, hangs just 1° or so above Venus, just above the west horizon in bright twilight. Use optical aid starting 15 or 20 minutes after sunset. Good luck.

■ Standing atop Scorpius in the south after darkness is complete, and butting heads with Hercules much higher, is enormous Ophiuchus the Serpent-Holder. Just east of his east shoulder (Beta Ophiuchi or Cebalrai) is a dim V-shaped asterism like a smaller, fainter Hyades. This is part of the defunct constellation Taurus Poniatovii, "Poniatowski's Bull." The V is 2½° tall and stands almost vertically now.¹

The top two stars of the V are the faintest, magnitudes 4.8 and 5.5. The middle star of its left (east) side is the famous K-dwarf binary 70 Ophiuchi, visual magnitudes 4.2 and 6.2, distance just 17 light-years. 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 Beta Oph is the large, loose open cluster IC 4665, a binocular object. Read more about the whole scene in Matt Wedel's Binocular Highlight column in the August Sky & Telescope, page 43.

TUESDAY, AUGUST 6

■ Today we're finally halfway through summer. (Astronomical summer, that is. We're probably — hopefully — a little more than halfway through it temperature-wise.) The exact mid-moment between the June solstice and the September equinox comes today at 12:47 p.m. Eastern Daylight Time (16:47 UT). That minute is the exact top of the circle of the year.

■ So, W-shaped Cassiopeia, a constellation best known for fall and winter evenings, is already wheeling up in the north-northeast as evening advances. And at nightfall the Great Square of Pegasus, eternal emblem of fall, balances on one corner just over the eastern horizon.

WEDNESDAY, AUGUST 7

■ Have you been seeing any Perseid meteors yet? The shower should be at its best late on the nights of August 11-12 (next Sunday night) and 12-13 (Monday night). The shower ramps up for more than a week and a half before peak, then drops off more quickly. This year will bring a first-quarter Moon to the evening sky on the peak nights, but it will set by about midnight if not earlier.

Tonight the Moon is no problem at all; it's only a crescent and sets around the end of twilight.

THURSDAY, AUGUST 8

■ As twilight fades, spot the waxing crescent Moon low in the west. About a fist and a half upper left of it is Spica. A little farther upper right of the Moon is Denebola, the tail-tip of Leo, not quite as bright.

FRIDAY, AUGUST 9

■ Look west-southwest in late dusk to spot Spica just 4° or 5° upper left of the crescent Moon. Very high above or upper right of them is Arcturus, brighter and pale yellow-orangish.

SATURDAY, AUGUST 10

■ Now Spica shines a little farther to the Moon's right or lower right as twilight fades out.

SUNDAY, AUGUST 11

■ It's peak Perseid meteor night! And maybe the first of two. The actual peak of the shower is supposed to be from about 13h UT to 16h UT on the 12th, which is 9 a.m. to noon on the 12th Eastern Daylight Time; 6 to 9 a.m. Pacific Daylight time. That's not long after the ideal Perseid meteor-watching hours before dawn. But who knows, the next night could be just as good or nearly so.

In early evening the meteors will be few, but those that do appear will be Earth-grazers skimming far across the top of the atmosphere. As the hours pass and the shower's radiant (in northern Perseus near Cassiopeia) rises higher in the northeast, the meteors will become shorter and more numerous. The radiant is highest before dawn.

Layer up warmly even if the day was hot; remember about radiational cooling late at night under an open clear sky! A sleeping bag makes good mosquito armor, and use DEET on whatever parts of you remain exposed.

Bring a reclining lawn chair to a dark, open spot where no local lights get in your eyes. Lie back, and gaze up into the stars. Be patient. As your eyes adapt to the dark, you may see a meteor every minute or so on average as night grows late. You'll see fewer under light pollution, but the brightest ones will shine through.

The best direction to look is wherever your sky is darkest, usually overhead. The shower's radiant (the meteors' perspective point of origin, if you could see them coming from far away in space) is in northern Perseus under Cassiopeia. But the meteors only become visible when they hit the upper atmosphere, and this can occur anywhere in your sky.

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This Week's Planet Roundup

Mercury disappears down into the sunset early this week. Your last chance may be around Friday August 2nd; see the top of this page.

Venus, magnitude –3.8, is getting very slightly more visible week by week, very low above the west horizon in bright twilight. Scan for it a little to the right of due west starting 15 or 20 minutes after sundown. Binoculars will help. Much will depend on the clarity of the air; humid means hazy. Good luck.

Mars and Jupiter (magnitudes +0.9 and –2.1, respectively, in Taurus) rise around 1 or 2 a.m. daylight-saving time, depending on your location, with Mars-like Aldebaran tagging along to their right. Watch for the trio to come up in the east-northeast.

Mars shines upper right of brighter Jupiter, closer to it day by day. On the morning of August 3rd the two planets are 5½° apart. They close to 0.3° for their conjunction on the 14th. Above all three points are the Pleiades.

As dawn overtakes the scene, the whole array is much higher in the east with Orion beneath them. See below.

Saturn (magnitude +0.8, near the Aquarius-Pisces border) rises in the east around the end of twilight. Watch for it to the lower right of the Great Square of Pegasus, which is balancing on one corner. The Square's top-right edge points diagonally down nearly to Saturn, two fists at arm's length away.

Saturn reaches its highest position in the south, in the steadiest atmospheric seeing for a telescope, in the hours before the start of dawn.

Uranus (magnitude 5.7, near the Aries-Taurus border) is well to the upper right of Mars and Jupiter before dawn begins. You'll need a good finder chart to identify it among surrounding faint stars.

Neptune (a tougher magnitude 7.8, near the Circlet of Pisces) is 11° east of Saturn before dawn begins. Again you'll need a proper finder chart.

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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.

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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.

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.

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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.

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"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

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1. Taurus Poniatovii was invented by the rector of Vilnius University, Marcin Poczobut, in 1773 to honor 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

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 in France 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 building? If you find Taurus Poniatovii on the wall where it was born, please send me pics: [email protected].

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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:

This went over very badly outside England. French astronomers called the planet Herschel instead, following the lead of Charles Messier. Others proposed Astraea, Cybele, Minerva, and more names. After bitter international debates and assertions of wounded pride, astronomers beyond England finally 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 years.

All well and good. But the name "Uranus" was actually proposed just four months after Herschel named the planet for his patron, by the German astronomer Johann Elert Bode. I've wondered if Bode may have had a covert second purpose for this name — its last four letters mean the same in Latin and English — as a low joke for "kiss-ass," a crude term for "obnoxious sycophant" that was already in use at the time in both English and German.

I've never seen a trace of evidence for this notion, other than the name being the butt of jokes for at least 143 years now. (Albert Stern has attempted to find the first recorded Uranus joke. The earliest clear one he found, looking only in U.S. publications, is from 1881, though he turned up possibles from the 1870s and 1852.) Elsewhere we read, "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 pranking his emigré former countryman for sucking up to the English king?

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