#astronomy This Week’s Sky at a Look, April 9 – 17 – Sky & Telescope

April 10, 2021 - Comment

Nova Cassiopeiae 2021 (V1405 Cas) was nonetheless holding on at about magnitude eight.three as of April ninth. See Vibrant Nova Erupts in Cassiopeia. Comet ATLAS, at the moment ninth or 10th magnitude, is excessive within the early-morning sky transferring from Aquila towards Hercules, awaiting 6-inch and bigger telescopes. See Bob King’s Make the Most of

Nova Cassiopeiae 2021 (V1405 Cas) was nonetheless holding on at about magnitude eight.three as of April ninth. See Vibrant Nova Erupts in Cassiopeia.

Comet ATLAS, at the moment ninth or 10th magnitude, is excessive within the early-morning sky transferring from Aquila towards Hercules, awaiting 6-inch and bigger telescopes. See Bob King’s Make the Most of Comet ATLAS.

And on the finish of that article is information and a chart for the brand new Nova Sagittarii 2021 No. 2 simply off the spout of the Sagittarius Teapot. It is at the moment eighth magnitude and pretty properly up within the south-southeast earlier than the start of daybreak.



■ As the celebs start to come back out in late twilight, Arcturus, the intense Spring Star climbing up within the east, stands simply as excessive as Sirius, the brighter Winter Star descending within the southwest. They’re each about 20° or 25° excessive for skywatchers at mid-northern latitudes.

These are the 2 brightest stars within the sky on the time. However Capella is a really shut runner-up to Arcturus. Spot it a lot increased within the northwest in early night.


■ By late night the Sickle of Leo stands practically vertical excessive within the south. Its backside star is Regulus, the brightest of Leo. Leo himself is strolling westward. The Sickle kinds his entrance leg, chest, mane, and a part of his head. Off to the left, an extended proper triangle kinds his hind finish and lengthy tail.

Spot brighter Procyon practically 4 fists to the suitable of Regulus and a bit decrease. About midway alongside that line and only a bit beneath, search for the dim head of Hydra, the Sea Serpent.


■ At the moment of 12 months, the 2 Canine Stars stand vertically aligned in late twilight. Look southwest. Sensible Sirius in Canis Main is beneath, and Procyon in Canis Minor is excessive above. They’re roughly two fists aside.

■ That is additionally the time of 12 months when, because the final of twilight fades away, the bowl of the dim Little Dipper extends straight to the suitable of Polaris within the north.

Excessive above the end-stars of the Little Dipper’s bowl, you will discover the end-stars of the Massive Dipper’s bowl. That pair is nearly twice as broad aside.

■ New Moon (precise at 10:31 p.m. EDT).


■ Mars is crossing the road between the horntips of Taurus, Beta and Zeta Tauri, this night and tomorrow night.

Mars is just a bit brighter than Beta. However evaluate their colours: Beta is a bluish-white B7 star.


■ Vega, the intense “Summer time Star,” rises within the northeast in mid-evening. Precisely the place do you have to look ahead to it to come back up? Spot the Massive Dipper very excessive within the northeast. Take a look at Mizar on the bend of its deal with. In the event you can see Mizar’s tiny, shut companion Alcor (binoculars present it simply), comply with a line from Mizar by means of Alcor all the best way right down to the horizon. That is the place Vega will make its look.


■ Arcturus shines brightly within the east these evenings. It is the sharp finish of an extended, slim kite-shaped asterism shaped by the brightest stars of Bootes, the Cowherd. The kite is at the moment mendacity on its aspect, extending to Arcturus’s left. The pinnacle of the kite, on the far left, is bent barely upward. The kite is 23° lengthy, about two fist-widths at arm’s size.


■ The waxing crescent Moon shines close to Aldebaran and the Pleiades this night, as proven beneath.

This week each Mars and the Moon cross upward between the horntip stars of Taurus.


■ The waxing crescent Moon this night kinds a quadrilateral with Mars above it and Beta and fainter Zeta Tauri to the edges, as proven above.


■ Now the Moon shines higher left of tiny Mars, as proven above.

■ As Arcturus ascends the japanese sky, Capella (its shut match for brightness) is coming down within the northwest. They stand at precisely the identical peak above your horizon at some second between about 9 and 10 p.m. daylight-saving time, relying totally on how far east or west you reside in your time zone.


This Week’s Planet Roundup

Mercury, Venus, Uranus, and Neptune all stay out of sight within the glare of the Solar.

Mars (magnitude +1.four, in Taurus) shines excessive within the west after darkish. Watch it cross between Beta and Zeta Tauri, the horntips of Taurus, on April 12th and 13th. Mars is visibly fainter than orange Aldebaran down beneath it, to not point out brighter orange Betelgeuse to Mars’s left or decrease left. In a telescope Mars is a mere 5 arcseconds broad: a tiny, shimmering blob.

Jupiter and Saturn (each in Capricornus) are low within the southeast simply earlier than and through early daybreak. Saturn is barely the upper of the 2 (relying in your latitude), however it’s a lot dimmer at magnitude +zero.7. Jupiter shines at magnitude –2.1, about 13° to Saturn’s decrease left.

Jupiter’s Nice Purple Spot aspect, imaged on April third by Christopher Go from his tropical latitude of 10° north. The darkish dot just isn’t a moon’s shadow however darkish Callisto itself, caught in a uncommon equatorial transit throughout Jupiter.

South right here is up. The northern two thirds of the Equatorial Zone are pale orange tan moderately than white. It is bordered on the north by the darkish purple fringe of the North Equatorial Belt.

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.

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

Wish to develop into a greater astronomer? Study your means across the constellations. They’re the important thing to finding all the pieces 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 middle of every difficulty 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 exhibits stars to magnitude 7.6.

Pocket Sky Atlas cover, Jumbo editionThe Pocket Sky Atlas plots 30,796 stars to magnitude 7.6, and lots of of telescopic galaxies, star clusters, and nebulae amongst them. Proven right here is the Jumbo Version, which is in arduous covers and enlarged for simpler studying outside by purple flashlight. Pattern charts. Extra concerning the present editions.

Subsequent up is the bigger and deeper Sky Atlas 2000.zero, plotting stars to magnitude eight.5; practically 3 times as many. The subsequent up, as soon as you understand your means round, are the even bigger Interstellarum atlas (stars to magnitude 9.5) or Uranometria 2000.zero (stars to magnitude 9.75). And make sure you learn tips on how to use sky charts with a telescope.

You may additionally need a good deep-sky guidebook, reminiscent of 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 substitute charts? Not for rookies, I do not assume, 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 Yard Astronomer’s Information, “A full appreciation of the universe can’t come with out creating the talents to seek 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, take heed 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 isn’t that there is one thing new in our mind-set, it is that credulous and confused considering might be far 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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