This Week’s Sky at a Glance, August 6 – 14

Nova Cas fades. Nova Cassiopeiae 2021 has bounced round in brightness ever since erupting to magnitude 7.7 in March together with brightenings to magnitude 5.5 in early May and 6.0 round July twenty seventh. As of August fifth it was right down to about magnitude 8.2. Charts and comparison stars. It actually cannot maintain this up ceaselessly. . . .


■ Have you been seeing any Perseids meteors but? For now you may discover solely an occasional Perseid throughout your observing periods, however hold on. The bathe is because of peak late this coming Wednesday night time, August 11; see that date under. Already the sky is moonlessly darkish.

How do you inform a Perseid from a random sporadic meteor or a member of a lesser bathe that is at present energetic, the Delta Aquariids and the Kappa Cygnids? Just hint its path backward far throughout the sky. Does this line cross a level in northern Perseus under Cassiopeia? That’s the radiant of the Perseids: their perspective level of origin when you might see them approaching within the far distance.

In actuality you may see them solely at their final second as they plunge into Earth’s environment and that may occur wherever in your sky.


■ Bright Vega passes closest to overhead round 10 or 11 p.m. now, relying on how far east or west you might be in your time zone.

How carefully it misses your zenith relies on how far north or south you might be. It passes proper by means of your zenith when you’re at latitude 39° north (Washington DC, Cincinnati, Kansas City, Lake Tahoe). How carefully are you able to choose this simply by wanting?

Deneb crosses closest to the zenith two hours after Vega. But to see Deneb precisely straight up it is advisable to be farther north, at latitude 45°: Portland, Minneapolis, Montreal, southern France, northern Italy.


■ This is the time of year when the Big Dipper scoops down throughout night, as if to select up the water that it’s going to dump from excessive overhead early subsequent spring.

■ New Moon (precise at 9:50 a.m. EDT).


Crescent Moon passing Venus, Aug 9-11, 2021
A brand new lunation will get beneath way because the waxing crescent Moon returns to the night sky. Bright Venus may be very apparent. Tiny, faint Mars, very low in shiny twilight, can be a robust catch even with binoculars.

■ As twilight fades after sundown, search for the very skinny crescent Moon coming into view far to the suitable or decrease proper of Venus, as proven above.

Low, distant Mars, 3° or 4° left or decrease left of the Moon for North Americans, can be a problem certainly. It’s practically on the far facet of the Sun from us and solely magnitude 1.8, and it is swamped by thick air and low-altitude twilight.


■ Now the crescent Moon shines to the suitable of Venus in twilight, as proven above.

■ If you employ a telescope a lot you are most likely acquainted with Lyra overhead, harboring Vega, the Double-Double, and the Ring Nebula amongst different sights. And close by is Albireo, the beak of Cygnus and one of many sky’s best gold-and-blue double stars.

But between Albireo and Lyra, what concerning the much-overlooked globular cluster M56? At magnitude 8.3 you may even be capable of detect it with massive binoculars in a darkish sky. To pinpoint the spot, hone in with Matt Wedel’s “Lost in Space,” his Binocular Highlight column and chart for this lesser-known discover within the August Sky & Telescope, web page 43.


The Perseid meteor bathe ought to peak late tonight, and there is no moonlight to intrude!

Early within the night the meteors can be quite few, as a result of the bathe’s radiant will nonetheless be low (within the northeast). But for that very same motive, early-evening Perseids overhead can be unusually lengthy as they graze sideways by means of the uppermost environment. Later within the night time the meteors will change into extra quite a few (and shorter) because the radiant rises excessive they usually plunge extra immediately downward. The greatest present can be from about 11 or midnight till the primary gentle of daybreak on the twelfth; the later the higher.

Layer up warmly even when the day was sizzling; keep in mind about radiational cooling beneath a clear open sky. A sleeping bag will serve for heat and mosquito armor; use DEET the place you stay uncovered.

Bring a reclining garden chair to a darkish, open spot the place no native lights get in your eyes. Lie again, and gaze up into the stars. Be affected person. As your eyes adapt to the darkish, you may even see a meteor each couple of minutes through the night, and each minute or so on common because the morning hours advance. You’ll see fewer beneath gentle air pollution, however the brightest ones will nonetheless shine by means of. The greatest route to look is wherever your sky is darkest, often overhead.

For rather more see Bob King’s Fine Show Expected from the Perseid Meteor Shower. And you may comply with the International Meteor Organization’s activity graph of the bathe to date. It’s based mostly on visible meteor counts by observers across the globe carried out by fastidiously standardized strategies to make them inter-comparable.


■ The curve of the crescent Moon this night factors towards Venus some two fists at arm’s size to the Moon’s decrease proper. Look for fainter Spica about half as far to the Moon’s left.

■ In good seeing, a telescope ought to present the tiny black shadow of Jupiter’s moon Io leaving Jupiter’s western edge at 10:14 p.m. EDT (begin wanting earlier!), carefully adopted by Io itself budding off from Jupiter’s edge 10 minutes later.

■ The Big Dipper hangs diagonally within the northwest after darkish. From its midpoint, look to the suitable to search out Polaris (not very shiny) glimmering due north as all the time.

Polaris is the tip of the Little Dipper’s deal with. The solely different Little Dipper stars which might be even reasonably shiny are the 2 forming the outer finish of its bowl: 2nd-magnitude Kochab and Third-magnitude Pherkad. On August evenings you may discover them to Polaris’s higher left (by about a fist and a half). They’re referred to as the Guardians of the Pole, since they ceaselessly circle round Polaris by means of the night time and thru the year.


■ As the stars come out, search for Spica decrease proper of the Moon. They’re lower than a fist at arm’s size aside. High to their higher proper shines Arcturus.


■ The brightest star excessive within the southeast these evenings is Altair, with little orange Tarazed above it by a finger-width at arm’s size. A little bit greater than a fist-width to Altair’s left is delicate Delphinus, the Dolphin, leaping left.

Above Altair, barely much less far, is smaller, fainter Sagitta, the Arrow. It too is pointing leftward.



This Week’s Planet Roundup

Mercury is buried deep within the sundown, decrease proper of dimmer Mars.

Venus (sensible at magnitude –3.9) shines due west throughout twilight. It units round twilight’s finish.

Mars is deep within the sundown, very far to Venus’s decrease proper.

Jupiter and Saturn (magnitudes –2.9 and +0.2, respectively, in or close to Capricornus) shine within the southeast in late twilight and after darkish. Jupiter begins the night time lowest, but it surely’s by far the brighter of the 2. Saturn glows yellowly 19° (about two fists at arm’s size) to Jupiter’s higher proper. The pair ranges out round 11 or midnight daylight-saving time. By then they’re practically at their highest within the south, at their telescopic greatest.

Saturn reached opposition on August 1st. Jupiter will accomplish that on August nineteenth. So this month they’re at their closest, greatest, and brightest of the year. See “Saturnian Challenges” beginning on web page 52 of the July Sky & Telescope, additionally “Action at Jupiter” within the August issue, web page 50, and “Dog Days with the Gas Giants” on web page 40 of August.

Jupiter on July 12, 2021
Jupiter on July twelfth, imaged by Christopher Go. South is up. The South and North Equatorial Belts have principally diminished to slim darkish traces. Red barges and 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 exhibits element within the broad A Ring, in addition to the skinny Encke Gap simply contained in the outer fringe of the outer B Ring. Agapios Elia of Nicosia, Cyprus, took video throughout 45 minutes on July 25, 2021, 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) is properly up within the east after midnight.

Neptune (magnitude 7.8, at the Aquarius-Pisces border 24° east of Jupiter) is 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 depend upon longitude (primarily Moon positions) are for North America.

Eastern Daylight Time, EDT, is Universal Time minus 4 hours. Universal Time is often known as UT, UTC, GMT, or Z time. To change into extra professional about time techniques than 99% of the folks you may ever meet, see our compact article Time and the Amateur Astronomer.

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

This is an out of doors nature pastime. For an easy-to-use constellation information masking the entire night sky, use the massive month-to-month map within the heart of every problem of Sky & Telescope, the important journal of astronomy.

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

Pocket Sky Atlas cover, Jumbo edition
The Pocket Sky Atlas plots 30,796 stars to magnitude 7.6, and lots 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 red flashlight. Sample charts. More about the current 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 your way 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 how to use sky charts with a telescope.

You’ll additionally need a good deep-sky guidebook, equivalent 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 learners, I do not assume, and never on mounts and tripods which might be lower than top-quality mechanically, which 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 beneath the night sky together with your
earbuds in place, hearken to Kelly Beatty’s month-to-month
podcast tour of the heavens above. It’s free.

            — Carl Sagan, 1996

“Facts are stubborn things.”
            — John Adams, 1770

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