#astronomy This Week’s Sky at a Look, Aug. 27 – Sept. four – Sky & Telescope

August 27, 2021 - Comment

RS Ophiuchi slows its fading. On August eighth the recurrent nova RS Ophiuchi lept from its regular magnitude 11.2 to four.eight, dim naked-eye brightness, after 15 years of simmering quietly close to minimal. It fading quickly at first, then rather more slowly. As of August 26th it had remained about magnitude eight.zero for 4 days

RS Ophiuchi slows its fading. On August eighth the recurrent nova RS Ophiuchi lept from its regular magnitude 11.2 to four.eight, dim naked-eye brightness, after 15 years of simmering quietly close to minimal. It fading quickly at first, then rather more slowly. As of August 26th it had remained about magnitude eight.zero for 4 days and was reddening. See Bob King’s Recurrent Nova RS Ophiuchi Simply Blew its High! with finder charts and comparability stars. Ophiuchus is ideally positioned excessive within the early night sky.

Nova Cassiopeiae 2021, in the meantime, has bounced round in brightness ever because it erupted from 15th magnitude to 7.7 final March. Its greatest bumps had been to magnitude 5.5 in early Might and 6.zero round July 27th. As of August 26th it additionally had been holding at eight.zero for a number of days, after it dipped to eight.6 earlier in August. Cassiopeia too is excellently positioned within the night sky. Charts and comparability stars.


■ Every time brilliant Vega crosses nearest your zenith, because it does quickly after darkish now, 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-shaped Capricornus down beneath it to face at their highest due south. This season, in fact, Capricornus is way outshone its company Jupiter and Saturn.

Week by week Jupiter and Saturn come into sight ever greater in twilight, as seen right here.


■ Now that the Moon is out of the night sky, this week is prime Milky Means time! After darkish, the Milky Means runs from Sagittarius within the south, up and a bit left left throughout Aquila and Cygnus excessive overhead, and on down by way of Cassiopeia to Perseus low within the north-northeast.

Cygnus sports activities the Cygnus Star Cloud, one of many Milky Means’s richest areas. Discover in depth all by way of right here with binoculars or a small scope utilizing Matt Wedel’s “Touring Cygnus with Binoculars” article and large chart within the September Sky & Telescope, beginning on web page 34.

Although the waning moon is gone from the early night sky, it is very a lot current from the midnight by way of daybreak. Watch it march throughout Taurus from Sunday by way of Tuesday mornings.


■ Final-quarter Moon tonight (precisely last-quarter at three:13 a.m. August 30th EDT). The Moon rises round 11 or midnight native time. It is in Taurus, between the Pleiades cluster above it and, as soon as it climbs excessive sufficient, orange Aldebaran beneath it. By early daybreak on the 30th the scene shifts considerably, as proven above.


■ Late these evenings as autumn approaches, Fomalhaut, the Autumn Star, makes its inevitable look above the southeast horizon. Its rising time will depend upon the place you reside. However by about 10 or 11 p.m. you should not have any bother recognizing it low within the southeast; simply discover an open view in that course. This 12 months Fomalhaut is simpler to find than ordinary: Look about two fists beneath Jupiter and a bit left.


■ An indication of the advancing season: Cassiopeia is excessive within the northeast, its W sample tilting up. And beneath it, starry Perseus is reaching up.

The best a part of Perseus contains the wintry Double Cluster. To search out 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 are on the lookout for what looks as if a small spot of enhanced Milky Means glow. Binoculars or a finderscope will show you how to detect the Double Cluster even by way of a good quantity of sunshine air pollution. The pair is a glory in a telescope.


■ As August wanes and nights start to show chilly, the Nice Sq. 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 suits inside it.

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

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


■ The precise Little Dipper, in the meantime, is tipping over leftward within the north. It is solely 40% so long as the Andromegasus Dipper, and most of it’s a lot fainter. As all the time, you will discover that it is oriented greater than 90° counterclockwise in comparison with Andromegasus. It is at present dumping its contents out.

■ Low within the northwest or north on the finish of summer time twilights, would you acknowledge noctilucent clouds if you happen to noticed them? They’re essentially the most astronomical of all cloud sorts, with their excessive altitude and formation on meteoric mud particles. They usually’re pretty uncommon — although turning into extra widespread lately because the ambiance modifications. See Bob King’s article.

■ Earlier than and through early daybreak Friday morning the third, the waning crescent Moon hangs beneath Castor and Pollux within the east. Far to the best of this tableau, Orion has already risen excessive to warn that winter is coming.

Look far beneath Orion for Sirius. Between Sirius and the Moon shines Procyon.


■ The approaching of September signifies that Scorpius, the proudly starring constellation of the southern sky in July, is tilting over and mendacity low within the southwest after darkish, getting ready to mattress down and drift off for the season.

The skinny waning Moon steps down within the east-northeast within the dawns of Saturday and Sunday September 4th and fifth. On the sixth, shortly earlier than dawn, it’ll nearly definitely be too low and slim to detect even with binoculars or a telescope, even when the air could be very clear; the Moon will likely be solely about 16 hours from new for East-Coast crescent hunters, and solely about 13 hours from new earlier than dawn within the Pacific time zone.


■ Look rigorously at Venus low within the west-southwest as twilight fades. Tonight Spica, just one/100 as brilliant, glimmers 1.eight° to Venus’s decrease left.

Tomorrow they will be 1.6° aside.


This Week’s Planet Roundup

Mercury (magnitude zero.zero) could be very deep within the sundown, about 16° decrease proper of Venus all week. You might need an opportunity at it with binoculars or a wide-field scope. About 15 or 20 minutes after sundown, scan for it simply above your horizon due west. Good luck.

Venus, sensible at magnitude –four.zero, shines brilliant 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 +zero.three, respectively, in Capricornus.

Jupiter begins the night lowest. Saturn glows 18° (about two fists) to Jupiter’s higher proper. The pair ranges out round 10 p.m. daylight-saving time. By then they’re nearing their highest within the south, at their telescopic finest.

Saturn reached opposition on August 1st, Jupiter on August 19th. In order that they’re nonetheless almost at their closest, greatest, and brightest of the 12 months. See “Saturnian Challenges” beginning on web page 52 of the July Sky & Telescope, additionally “Canine Days with the Fuel Giants” on web page 40 of August.

Three satellites on Jupiter, two shadow transits, and extra! “The day I’ve been ready for all 12 months has lastly come,” wrote Christopher Go from the Philippines on August 15th. “At present we had a grand slam occasion. A really uncommon triple transit on Jupiter with the moons Callisto, Ganymede and Europa in transit. As a bonus, eclipsed Io was seen simply earlier than it went behind Jupiter. After the triple transit there was a really uncommon occasion when Ganymede occulted Europa adopted by Ganymede eclipsing Europa! Seeing the shadow of Ganymede over Europa was surreal! Every thing went PERFECTLY. Seeing was unimaginable and the sky was completely clear!” Within the photos right here, north is up.

However the easiest way to observe the sequence of occasions is by video! The Washington Submit put all of it collectively together with a step-by-step information to every part that is taking place. Here is the story: Watch this ‘surreal’ Jupiter eclipse that you just in all probability missed.

Saturn on July 25, 2021Saturn on July 25th. North is up. This beautiful stacked-video picture reveals element within the broad B Ring, in addition to the skinny Encke Hole simply contained in the outer fringe of the outer A Ring. Saturn’s Equatorial Zone is brilliant as ordinary, and its North Equatorial Belt is distinct. The slender darkish band seemingly on the opposite facet of the Equatorial Zone is definitely the dim, interior 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 finest frames.

Uranus (magnitude 5.7, in Aries) and Neptune (magnitude 7.eight, on 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 depend upon longitude (primarily Moon positions) are for North America.

Jap Daylight Time, EDT, is Common Time minus four hours. Common Time is also called UT, UTC, GMT, or Z time. To change into extra knowledgeable about time methods than 99% of the folks you will ever meet, see our compact article Time and the Novice Astronomer.

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

That is an out of doors nature interest. For an easy-to-use constellation information protecting the entire night sky, use the large month-to-month map within the heart of every situation of Sky & Telescope, the important journal of astronomy.

When you get a telescope, to place it to good use you will want an in depth, large-scale sky atlas (set of charts). The fundamental customary is the Pocket Sky Atlas (in both the unique or Jumbo Version), which reveals stars to magnitude 7.6.

Pocket Sky Atlas cover, Jumbo editionThe Pocket Sky Atlas plots 30,796 stars to magnitude 7.6, and a whole lot of telescopic galaxies, star clusters, and nebulae amongst them. Proven right here is the Jumbo Version, which is in laborious covers and enlarged for simpler studying outdoor by crimson flashlight. Pattern charts. Extra in regards to the present editions.

Subsequent up is the bigger and deeper Sky Atlas 2000.zero, plotting stars to magnitude eight.5; almost thrice as many. The subsequent up, as soon as your manner round, are the even bigger Interstellarum atlas (stars to magnitude 9.5) or Uranometria 2000.zero (stars to magnitude 9.75). And be sure you learn learn how to use sky charts with a telescope.

You will additionally need a good deep-sky guidebook, similar to Sky Atlas 2000.zero Companion by Sturdy and Sinnott, or the larger (and illustrated) Evening Sky Observer’s Information by Kepple and Sanner.

Can a computerized telescope exchange charts? Not for inexperienced persons, I do not assume, and never on mounts and tripods which can be lower than top-quality mechanically, that means heavy and costly. And as Terence Dickinson and Alan Dyer say of their Yard Astronomer’s Information, “A full appreciation of the universe can’t come with out creating the talents to search out issues within the sky and understanding how the sky works. This data comes solely by spending time below the celebs with star maps in hand.”

Audio sky tour. Out below the night sky along with your
earbuds in place, hearken to Kelly Beatty’s month-to-month
podcast tour of the heavens above. It is free.

“The hazards of not considering clearly are a lot better now than ever earlier than. It is not that there is one thing new in our mind-set, it is that credulous and confused considering may be rather more deadly in methods it was by no means earlier than.”
            — Carl Sagan, 1996

“Info are cussed issues.”
            — John Adams, 1770


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