This Week’s Sky at a Glance, August 20 – 28 – Sky & Telescope


RS Ophiuchi fades. On August eighth the well-known recurrent nova RS Ophiuchi lept from its regular magnitude 11.2 to 4.8, dim bare-eye magnitude, after 15 years of simmering quietude. It’s fading quickly now, as previously. See Bob King’s Recurrent Nova RS Ophiuchi Just Blew its Top! with finder charts and comparability stars. Ophiuchus is ideally positioned excessive within the night sky.

Nova Cassiopeiae 2021, in the meantime, has bounced round in brightness ever because it erupted from 15th magnitude to 7.7 in March. Among its bumps had been brightenings to magnitude 5.5 in early May and 6.Zero round July 27th. As of August 12th it was all the way down to about 8.5. Cas too is excellently positioned within the night sky. Charts and comparability stars.

FRIDAY, AUGUST 20

■ The Moon shines underneath Saturn this night, and Jupiter shines to their left, as proven beneath.

As the Moon turns full it hangs underneath Saturn, then Jupiter — which, not coincidentally, are at opposition this month. This scene is in twilight; within the subsequent few hours watch the entire sample climb and switch clockwise.

■ The two brightest stars of summer season are Vega, now overhead shortly after dusk, and Arcturus, shining within the west. Draw a line down from Vega to Arcturus. A 3rd of the way in which down, the road crosses the dim Keystone of Hercules. Two thirds of the way in which down it crosses the dim semicircle of Corona Borealis with its one modestly brilliant star, Alphecca or Gemma.

Also: Vega and the Keystone star closest to it type an equilateral triangle with Eltanin to their north, the nostril of Draco the Dragon. Eltanin is the brightest star of Draco’s quadrilateral head; he is eyeing Vega.

SATURDAY, AUGUST 21

■ Now the Moon shines underneath Jupiter, with Saturn to their proper. The Moon is full tonight and tomorrow night time; precise full part happens at 9:02 a.m. tomorrow morning, splitting the date distinction (for night skywatchers within the Americas).

■ As summer season progresses and Arcturus strikes down the western sky, the kite determine of Bootes sprouting up from Arcturus tilts to the proper (relying in your latitude). The kite is slim, barely bent with its prime leaning proper, and 23° lengthy: about two fists at arm’s size. Arcturus is its backside level the place the stubby tail is tied on.

The Big Dipper now slants at about the identical peak within the northwest, to the Kite’s proper.

SUNDAY, AUGUST 22

■ The Moon once more varieties a massive curving arc with Jupiter and Saturn, however now they’re to the Moon’s proper. The arc spans three fists at arm’s size. MONDAY, AUGUST 23

■ By 10 or 11 p.m. the waning Moon is nicely up within the east-southeast. Spot brilliant Jupiter off to its higher proper. They type a practically equilateral triangle with Fomalhaut, the Autumn Star, rising beneath Jupiter. How early and low are you able to first see it? Is this your first sighting of Fomalhaut for this 12 months’s apparition?

TUESDAY, AUGUST 24

■ Another signal of the advancing season: Cassiopeia is excessive within the northeast, its W sample tilting up. And beneath it, starry Perseus is reaching up.The highest a part of Perseus consists of the wintry Double Cluster. To discover it, look beneath the bottom two stars of the Cassiopeia W (they’re the faintest two), by considerably extra that the gap between them. You’re on the lookout for what looks like a small spot of enhanced Milky Way glow. Binoculars or a finderscope will make it easier to detect the Double Cluster even via a honest quantity of sunshine air pollution. The pair are a glory in a telescope.

WEDNESDAY, AUGUST 25

■ As August proceeds and nights start to show chilly, the Great Square of Pegasus looms up within the east, balancing on one nook. Its stars are solely 2nd and third magnitude, and your fist at arm’s size matches inside it.

From the Square’s left nook extends the principle line of the constellation Andromeda: three stars (together with the nook) about as brilliant as these forming the Square.

This entire big sample was named “the Andromegasus Dipper” by the late Sky & Telescope columnist George Lovi. It’s formed form of like a big Little Dipper with an additional-massive bowl, and it is at present lifting its contents upward.

THURSDAY, AUGUST 26

■ Low within the northwest or north at the top of summer season twilights, would you acknowledge noctilucent clouds for those who noticed them? They’re probably the most astronomical of all cloud varieties, with their excessive altitude and formation on meteoric mud particles. And they’re pretty uncommon — although changing into extra widespread in recent times because the environment modifications. See Bob King’s article.

FRIDAY, AUGUST 27

■ Whenever brilliant Vega crosses nearest your zenith, because it does proper after darkish now, you understand that the Sagittarius Teapot is at its highest due south.

Two hours later when Deneb crosses closest to the zenith, it is the flip of little Delphinus and boat-formed Capricornus down beneath it to face at their highest due south.

With the passing weeks, Jupiter and Saturn seem ever increased as the celebrities come out.

SATURDAY, AUGUST 28

■ Now that the Moon is out of the night sky, it is prime Milky Way time. After darkish, the Milky Way runs from Sagittarius within the south, up and a bit left left throughout Aquila and thru the large Summer Triangle excessive overhead, and on down via Cassiopeia to Perseus low within the north-northeast.

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This Week’s Planet Roundup

Mercury may be very deep within the sundown and fading additional, from magnitude –0.Four to –0.1 this week. You may need a probability at it with binoculars or a extensive-discipline scope. About 15 or 20 minutes after sundown, scan for it simply above your west horizon about 18° (practically two fists at arm’s size) decrease proper of Venus. Good luck.

Venus, good at magnitude –3.9, shines pure white within the west-southwest throughout twilight. It nonetheless units round twilight’s finish.

Jupiter and Saturn shine within the southeast in late twilight and after darkish. They’re magnitudes –2.9 and +0.2, respectively, in Capricornus.Jupiter begins the night time lowest. Saturn glows 18° (about two fists) to Jupiter’s higher proper. The pair ranges out round 11 p.m. daylight-saving time. By then they’re about at their highest within the south, at their telescopic greatest.

Saturn reached opposition on August 1st, and Jupiter did so on August 19th. So this month they’re at their closest, largest, and brightest of the 12 months. See “Saturnian Challenges” beginning on web page 52 of the July Sky & Telescope, additionally “Action at Jupiter” within the August concern, web page 50, and “Dog Days with the Gas Giants” on web page 40 of August.

Jupiter’s Great Red Spot facet, imaged on August seventh by Christopher Go with a 14-inch Schmidt-Cassegrain scope. As is commonplace for planets that is a stacked-video picture, manufactured from many frames chosen for sharpness after which de-rotated in software program to compensate for the planet’s rotation throughout a lengthy video session. In this picture the colours and distinction are enhanced. South is up.Note the positive element within the Great Red Spot! The South and North Equatorial Belts have principally diminished to slim darkish-reddish strains. Dark crimson spots proceed simply north of the NEB. Much of the Equatorial Zone continues pale yellow-tan.

Saturn on July 25. North is up. This beautiful stacked-video picture reveals element within the broad A Ring, in addition to the skinny Encke Gap simply contained in the outer fringe of the outer B Ring. Saturn’s Equatorial Zone is brilliant as standard, and its North Equatorial Belt is distinct. The slim darkish band seemingly on the opposite facet of the equatorial Zone is definitely the dim, internal C ring. Agapios Elia of Nicosia, Cyprus, took video throughout 45 minutes on July 25th utilizing a 9.25-inch Schmidt-Cassegrain scope. He de-rotated the globe throughout processing after which stacked massive numbers of the of greatest frames.

Uranus (magnitude 5.7, in Aries) and Neptune (magnitude 7.8, at the Aquarius-Pisces border) are excessive within the southeast to south within the early-morning hours.

All descriptions that relate to your horizon — together with the phrases up, down, proper, and left — are written for the world’s mid-northern latitudes. Descriptions that additionally rely upon longitude (primarily Moon positions) are for North America.

Eastern Daylight Time, EDT, is Universal Time minus Four hours. Universal Time is often known as UT, UTC, GMT, or Z time. To change into extra professional about time methods than 99% of the individuals you will ever meet, see our compact article Time and the Amateur Astronomer.

Want to change into a higher astronomer? Learn your manner across the constellations. They’re the important thing to finding every part fainter and deeper to hunt with binoculars or a telescope.

This is an outside nature passion. For a straightforward-to-use constellation information protecting the entire night sky, use the large month-to-month map within the middle of every concern of Sky & Telescope, the important journal of astronomy.

Once you get a telescope, to place it to good use you will want a detailed, massive-scale sky atlas (set of charts). The primary commonplace is the Pocket Sky Atlas (in both the unique or Jumbo Edition), which reveals stars to magnitude 7.6.

The Pocket Sky Atlas plots 30,796 stars to magnitude 7.6, and tons of of telescopic galaxies, star clusters, and nebulae amongst them. Shown right here is the Jumbo Edition, which is in exhausting covers and enlarged for simpler studying open air by crimson flashlight. Sample charts. More concerning the present editions.

Next up is the bigger and deeper Sky Atlas 2000.0, plotting stars to magnitude 8.5; practically thrice as many. The subsequent up, as soon as you understand your manner round, are the even bigger Interstellarum atlas (stars to magnitude 9.5) or Uranometria 2000.0 (stars to magnitude 9.75). And make sure to learn methods to use sky charts with a telescope.

You’ll additionally need a good deep-sky guidebook, comparable to Sky Atlas 2000.0 Companion by Strong and Sinnott, or the larger (and illustrated) Night Sky Observer’s Guide by Kepple and Sanner.

Can a computerized telescope substitute charts? Not for novices, I do not assume, and never on mounts and tripods which are lower than prime-high quality mechanically, that means heavy and costly. And as Terence Dickinson and Alan Dyer say of 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.”

Audio sky tour. Out underneath the night sky with yourearbuds in place, take heed to Kelly Beatty’s monthlypodcast tour of the 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

 



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