This Week’s Sky at a Glance, June 11 – 19 – Sky & Telescope

Nova Cassiopeiae nonetheless continues. It has been 12 weeks since Nova Cas 2021 to magnitude 7.7. Surprisingly, it has stayed roughly that brilliant ever since apart from swelling to five.3, faint naked-eye visibility, for per week in early-mid Might earlier than dropping again to 7.7. As of June 10th it had crept again as much as 7.0.

The nova is reasonably low within the north-northeast after darkish, relying in your latitude. It greater by the evening and stands very excessive earlier than daybreak. Charts and comparability stars.

, JUNE 11

■ Vivid Venus and the skinny Moon type a mystic pair low within the -northwest in twilight, as proven beneath. They will be 3° or 4° aside for skywatchers close to the US East Coast, and solely 2° aside by the point of twilight for the West Coast. Your finest view is likely to be about 35 to 45 minutes after sundown, earlier than they get too low.

The Moon, recent from eclipsing the Solar when it was new on the 10th, now reappears as a skinny, day-and-a-half previous crescent close to Venus. Within the subsequent two days it’ll wax up previous Gemini’s head stars and Mars.


■ The Large 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 looking out 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 bit after. How exactly are you able to time this occasion in your location, maybe utilizing the vertical fringe of a constructing?

■ After darkish, look south-southeast for orange Antares, “the Betelgeuse of summer season.” (Each are 1st-magnitude “crimson” supergiants). Round and higher proper of Antares, the opposite, whiter stars of higher Scorpius type 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. Discover the center one, Delta Scorpii. It is clearly brighter than the opposite two, proper? For a few 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 brilliant for a lot of the years ever since, although 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. To this point this yr it is remained brilliant at 1.9. It is a extremely , fast-rotating B star that apparently has been throwing off materials from its equator.


■ Spot Mars beneath the crescent Moon this night. Mars is now fainter than even Castor; see the Mars-Pollux-Castor lineup within the first illustration above.

As soon as the evening is absolutely darkish, use binoculars to identify the Beehive Star Cluster about 4° left of the Moon (for North America).


■ The central stars of the little constellation Lyra, forming a small triangle and parallelogram, dangle from brilliant Vega excessive within the east. The 2 brightest stars of the sample, after Vega, are the 2 forming the underside of the parallelogram: Beta and Gamma Lyrae, or Sheliak and Sulafat. They’re at present lined up vertically. Beta is the one on prime.

Beta Lyrae is an eclipsing binary star, one of many first found. Examine it to Gamma everytime you lookup at Lyra. Usually Beta is barely a hint dimmer than Gamma. Finally, nonetheless, you will catch Beta when shock! it’s fairly clearly dimmer than ordinary.


■ This night you will discover Regulus about 4° decrease left of the Moon, and Algieba (Gamma Leonis, not a lot fainter) higher proper of the Moon, as seen from North America.


■ After dusk, search for the Large Dipper hanging straight down within the northwest. Its backside two stars, the Pointers, level decrease proper towards modest Polaris, the top of the Little Dipper’s deal with.

That is the time of yr when, on the finish of twilight, the Little Dipper floats straight up from Polaris — maybe like a helium balloon escaped from some June night celebration. By means of mild air pollution or moonlight, all you might even see of the Little Dipper are Polaris at its backside and Kochab, the lip of the Little Dipper’s bowl, on the prime. The remainder of its stars are pretty dim at Third to fifth magnitude.


■ First-quarter Moon (actual at 11:54 p.m. EDT). Shining higher proper of the Moon you will discover 2nd-magnitude Denebola, Leo’s tail-tip. They are a fist or rather less aside.


■ Now the Moon shines near Third-magnitude Gamma (γ) Virginis, or Porrima. This can be a high-quality, shut, equal-brightness double star for telescopes. The elements are 3.1 arcseconds aside now and widening barely yr by yr. They’re each F1 stars considerably bigger and warmer than the Solar, shining from 39 light-years away.

The Moon shines with Gamma Virginis, then over Spica. It will not really seem this near the celebs; the Moon right here is at all times drawn about thrice its precise obvious dimension.

■ We’re stepping into the time of yr when the 2 brightest stars of summer season, Arcturus and Vega, are about equally excessive overhead as night grows late: Arcturus towards the southwest, Vega towards the east.

Arcturus and Vega are 37 and 25 light-years away, respectively. They signify the 2 commonest kinds of naked-eye star: a yellow-orange Okay large and a white A main-sequence star. They’re 150 and 50 occasions brighter than the Solar, respectively — which, mixed with their nearness, is why they dominate the night star-scene.


■ Spica (260 light-years away) shines below the Moon, as proven above. A lot greater above them is brighter Arcturus. Spica is pale, icy blue-white. Arcturus is candleflame yellow-orange.

■ Spring ends and summer season begins, astronomically, on the solstice tomorrow the 20th.


This Week’s Planet Roundup

Mercury is out of sight within the glare of the Solar.

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

Mars (magnitude +1.8, in Most cancers) glows modestly low within the west-northwest proper after darkish, left or higher left of Castor and Pollux. Now on the far aspect of the Solar from us, Mars is nearly as faint and small as it will possibly ever get (at present 4.Zero arcseconds large).

Jupiter and Saturn (in Aquarius and Capricornus, respectively) rise in the course of the evening, Jupiter about an hour after Saturn. They shine at their highest and telescopic finest in early daybreak, a time when the atmospheric seeing usually steadies. Jupiter dominates at magnitude –2.5. Saturn, 19° to Jupiter’s proper, is a extra modest +0.5. They will attain opposition in August.

As daybreak begins, look 20° beneath Jupiter for Fomalhaut, the “Autumn Star.” It is rising from the dawn glow even earlier than the official begin of summer season.

Jupiter’s Nice Purple Spot was crossing the planet’s central meridian on Might 21st 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.

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

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

Uranus, in Aries, has barely risen within the east as daybreak begins.

Neptune, in Aquarius 21° east of Jupiter, lurks at eighth magnitude 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 rely on longitude (primarily Moon positions) are for North America.

Japanese Daylight Time, EDT, is Common Time minus Four hours. Common Time is also referred to as UT, UTC, GMT, or Z time. To change into extra skilled about time programs than 99% of the individuals you will ever meet, see our compact article Time and the Novice Astronomer.

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

That 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 challenge 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- sky atlas (set of charts). The fundamental 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 a whole bunch of telescopic galaxies, star clusters, and nebulae amongst them. Proven right here is the Jumbo Version, which is in onerous covers and enlarged for simpler studying outdoor by crimson flashlight. Sample charts. Extra in regards to the present editions.

Subsequent up is the bigger and deeper Sky Atlas 2000.0, plotting stars to magnitude 8.5; practically thrice as many. The following up, as soon as your approach 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 one can use sky charts with a telescope.

You will additionally need a good deep-sky guidebook, akin to Sky Atlas 2000.0 Companion by Sturdy 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 can be lower than top-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 can not come with out creating the abilities 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 together with your
earbuds in place, hearken to Kelly Beatty’s month-to-month
podcast tour of the heavens above. It is free.

“The risks of not pondering 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 pondering will be rather more deadly in methods it was by no means earlier than.”
            — Carl Sagan, 1996

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


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