This Week’s Sky at a Glance, June 4 – 12

Nova Cassiopeiae, continued: It’s been 11 weeks since Nova Cas 2021 erupted to magnitude 7.7. Surprisingly, it has stayed about that shiny ever since apart from swelling to five.3, faint naked-eye visibility, for a week in early-mid May. As of June 4th it was about 7.1.

The nova is low-ish within the north-northeast after darkish, relying in your latitude. It climbs larger by the night time and may be very excessive earlier than daybreak. Charts and comparison stars.


■ For a lot of the spring at our mid-northern latitudes, the Milky Way lies proper down out of sight throughout the horizon. But watch the east now. The wealthy Cepheus-Cygnus-Aquila stretch of the Milky Way looms up horizontally throughout the jap sky as night time advances, earlier and better every week. A touch for the light-polluted: The Milky Way runs horizontally beneath Vega, proper alongside the underside of the Summer Triangle.

Mars stands left of Pollux and Castor this week. On Friday the 4th it is nonetheless beneath the road fashioned by the 2 stars, as proven right here. It crosses their line on June seventh, then strikes farther to their higher left thereafter. Meanwhile, Venus shines at Castor’s ft.

■ Make your plans for the eclipse of the Sun Thursday morning June 10th! The eclipse might be annular from sparsely populated northern Ontario by components of the arctic. But a partial eclipse will happen throughout and after dawn if you happen to’re northeast of a line from North Carolina by North Dakota. In the US Northeast and jap Canada, the rising crescent Sun might be spectacular! You might want to scout a spot with a view to the east-northeast horizon. For particulars, maps, and native timetables, see Joe Rao’s article within the June Sky & Telescope, web page 34, or the smaller version online.

Europe and most of Russia will see the partially eclipsed Sun excessive in the midst of the day.


■ Have you ever seen Alpha Centauri? At declination –61° , our sensible, magnitude-zero neighbor is completely out of sight if you happen to’re north of latitude 29°. But if you happen to’re at the latitude of San Antonio, Orlando, or factors south, Alpha Cen skims simply above your southern true horizon for a couple of minutes late these evenings.

When does this occur? When do you have to look? Just about when Alpha Librae, the lower-right of Libra’s two brightest stars, is due south over your panorama. At that point, drop your gaze down from there!


■ The early dawns and shiny early mornings of the warm-weather season are a beautiful time to benefit from the open air uncrowded. Habitual slugabeds do not know what they’re lacking. If you are a type of adventurous few or if in case you have a crack-of-dawn commute take word: Jupiter and Saturn in early daybreak now kind a proper triangle with Fomalhaut, the out-of-season Autumn Star, way down beneath. Jupiter is the fitting angle.


■ Mars, Pollux, and Castor kind a straight line this night. Look pretty low within the west-northwest proper after nightfall. Mars is the one on the left. By tomorrow, Mars might be very barely above the road.


■ Here it’s simply 12 days to summer season. But as twilight fades, look very low within the north-northwest for wintry Capella very out of season. The farther north you’re, the upper it would seem. You might have binoculars. If you are as far north as Montreal or a Portland (both the one in Oregon or Maine), Capella is definitely circumpolar.


■ New Moon and an annular eclipse of the Sun tomorrow morning June 10th! The eclipse might be annular solely alongside a path from northern Ontario throughout components of the arctic. But throughout and after dawn, a partial eclipse will happen if you happen to’re northeast of a line from North Carolina by North Dakota.

In the US Northeast and jap Canada, the rising crescent Sun might be spectacular! For full particulars, maps, and native timetables, see Joe Rao’s article within the June Sky & Telescope, web page 34, or the shorter version online.

Europe and most of Russia will see the partially eclipsed Sun excessive in the midst of the day Thursday.


■ A huge asterism it’s possible you’ll not find out about is the Great Diamond, some 50° tall and increasing over 5 constellations. It now leans within the south to southwest after nightfall.

Start with Spica, its backside. High above Spica is shiny Arcturus. Almost as far higher proper from Arcturus is fainter Cor Caroli, third magnitude. The similar distance down from there’s Denebola, the 2nd-magnitude tailtip of Leo. And then again to Spica. Robert H. Baker might have been the primary to call the Great Diamond, in his 1954 guide When the Stars Come Out.

The backside three of those stars, the brightest, kind a practically excellent equilateral triangle. The first to call it the “Spring Triangle” was most likely Sky & Telescope columnist George Lovi, writing within the March 1974 concern. The title did not catch on at the time, so let’s strive once more!

■ Can you see the large Coma Berenices star cluster? Does your gentle air pollution actually conceal it, or do you simply not know precisely the place to look? It’s midway from Cor Caroli to Denebola.

The cluster’s brightest members kind an inverted Y. The total cluster is about 4° vast — a huge, dim glow in a pretty darkish sky, the scale of a ping-pong ball at arm’s size. It practically fills a binocular view.


■ Bright Venus and the skinny crescent Moon kind a mystic pair low within the west-northwest in twilight, as proven beneath. They’ll be 3° or 4° aside for skywatchers close to the US East Coast, and solely 2° by the point of twilight for the West Coast. Your greatest view is perhaps about 40 or 50 minutes after sundown, earlier than they get too low.

The Moon, contemporary from eclipsing the Sun when it was new on the tenth, now reappears as a skinny, day-and-a-half previous crescent close to Venus. In the following two days it waxes up previous the pinnacle stars of Gemini and Mars.


■ The Big Dipper hangs excessive within the northwest proper after darkish. The Dipper’s Pointers, at present its backside two stars, level decrease proper towards Polaris. Above Polaris, and searching similar to it, is Kochab, the lip of the Little Dipper’s bowl.

Kochab stands exactly above Polaris across the finish of twilight or a little after. How exactly are you able to time this occasion to your location, maybe utilizing the vertical fringe of a constructing?

■ After darkish, look south-southeast for orange Antares, “the Betelgeuse of summer.” (Both are 1st-magnitude “red” supergiants). Around and higher proper of Antares are the opposite, whiter stars of higher Scorpius, forming their distinctive sample. The remainder of the Scorpion extends down towards the horizon.

The row of three stars higher proper of Antares historically marks the Scorpion’s head. Notice the center one, Delta Scorpii. It’s clearly brighter than the opposite two, proper? For many years, maybe ages, it was solely a slight hint brighter than the one above it, Beta Scorpii. Then in July 2000 Delta practically doubled in brightness, altering the entire look of higher Scorpius. And it has stayed shiny for many of the years ever since, with fluctuations.

Scorpius because it seems these evenings. For judging the brightness of Delta Sco, Beta is magnitude 2.6 and Antares is 1.1. Delta Sco traditionally was magnitude 2.3. So far this year it is remained shiny at 1.9.


This Week’s Planet Roundup

Mercury is out of sight in inferior conjunction with the Sun.

Venus (magnitude –3.8, in decrease Gemini) shines low within the west-northwest throughout twilight. Catch it when you can; it units earlier than twilight ends.

Mars (magnitude +1.7, in higher Gemini) glows modestly low within the west-northwest proper after darkish, higher left of Venus and left of Pollux and Castor.

Mars begins the week beneath the Pollux-Castor line as proven at the highest of this web page. It crosses the road on June seventh.

Mars is sort of as distant because it will get on the far aspect of its orbit from us. So it is no brighter than even Castor, the fainter of the Pollux-and-Castor “twins.” And in a telescope, Mars is simply tiny blob 4 arcseconds vast.

Jupiter and Saturn (in dim Aquarius and Capricornus, respectively) rise round 1 a.m. and midnight, respectively (daylight-saving time). By the primary glimmer of daybreak they’re pretty excessive within the southeast, practically as excessive as they may get. Jupiter dominates at magnitude –2.5. Saturn, 18° to Jupiter’s proper, is a extra modest magazine +0.5.

Jupiter’s Great Red Spot was crossing the planet’s central meridian on May twenty first when Christopher Go took this stacked-video picture centered on 21:09 UT (when the System II central-meridian longitude was 358°). South is up.

Lower proper of the Red Spot are two of Jupiter’s satellites: darkish gray Ganymede and smaller, shiny orange Io with its darker polar areas. The black circle decrease left of the Red Spot is Io’s shadow. (The distinction of this picture has been boosted.)

A darkish line now practically encircles the Red Spot Hollow. It seems to be like a continuation of the 2 slender darkish bands at left; the entire thing has taken on the “snake head” sample we have seen earlier than. The Red Spot is the snake’s huge eye. His nostril factors proper (towards celestial east; following).

Don’t get too excited; Jupiter exhibits nowhere close to this degree of element visually, particularly from latitudes larger than Go’s near-equatorial 10° N. For these of us much less ideally positioned, Jupiter stays reasonably low in mediocre telescopic seeing at the same time as daybreak begins.

Uranus stays out of sight within the glow of daybreak.

Neptune, in Aquarius 21° east of Jupiter, lurks at eighth magnitude low within the east-southeast simply earlier than daybreak.

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 develop into extra professional about time programs than 99% of the folks you will ever meet, see our compact article Time and the Amateur Astronomer.

Want to develop 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 passion. For an easy-to-use constellation information masking 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, large-scale sky atlas (set of charts). The fundamental normal 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 tons of of telescopic galaxies, star clusters, and nebulae amongst them. Shown right here is the Jumbo Edition, which is in arduous 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 3 times as many. The subsequent up, as soon as you already know your way round, are the even bigger Interstellarum atlas (stars to magnitude 9.5) or Uranometria 2000.0 (stars to magnitude 9.75). And remember to learn how to use sky charts with a telescope.

You’ll additionally need a good deep-sky guidebook, akin 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 newcomers, I do not suppose, and never on mounts and tripods which are 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 along with your
earbuds in place, hearken to Kelly Beatty’s month-to-month
podcast 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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