This Week’s Sky at a Glance, April 23 – May 1 – Sky & Telescope

Novae replace:   Nova Cassiopeiae 2021 (V1405 Cas) was nonetheless holding at about magnitude 7.9 as of April 22nd. It has been about like that for 5 weeks now. However it has sunk very low within the north after dusk, particularly for observers at southerly latitudes, so that you’re higher off catching it when it is increased on the north-northeast earlier than the beginning of daybreak. See Vivid Nova Erupts in Cassiopeia.

That is fairly in contrast to the more moderen Nova Sagittarii 2021 No. 2 (V6595 Sgr) and Nova Scorpii 2021. Each of these have light from magnitude Eight or 8.5 to 11 or 11.5. See A Bouquet of Novae Brightens April Nights.

Comet ATLAS continues at about ninth magnitude. It is now crossing Corona Borealis and Bootes in tremendous, excessive view within the east by late night. See Make the Most of Comet ATLAS.


■ Venus and Mercury are starting their twilight emergence simply above the west-northwest horizon, as proven beneath, however they’re nonetheless very shy about it. Begin searching for them there with binoculars about 15 minutes after sundown. The farther north you’re the higher.

Are you able to catch Venus and maybe Mercury but? Scan with binoculars simply above the west-northwest horizon beginning about 15 minutes after sundown. Their visibility is exaggerated right here.
5 days later Mercury and Venus are considerably simpler.

These scenes are drawn for latitude 40° north. That is the place Mercury and Venus will seem lined up vertically as proven right here on the 30th. At completely different latitudes, you will them tilted by about the identical angle that your latitude differs from 40°.

The Arch of Spring. As night descends, look excessive within the west for Pollux and Castor lined up nearly horizontally (relying in your latitude). These two stars, the heads of the Gemini twins, kind the highest of the large Arch of Spring. To their decrease left is Procyon, the left finish of the Arch. Farther to their decrease proper is the opposite finish, fashioned by Menkalinan (Beta Aurigae) after which Capella.

This spring the Arch has an intruder: little Mars. It is not fairly midway from Capella to Procyon and, for many of the week, slightly beneath that line. The array sinks within the west by way of the night.

■ After darkish tonight the Moon shines on the alternative facet of the sky. Look higher left of it, by lower than fist at arm’s size, for 2nd-magnitude Denebola, the tail star of Leo.

Practically 4 fists left of the Moon shines brighter Arcturus, magnitude 0, the main mild of Bootes.


■ This night Arcturus shines about three fists left of the Moon.

And look beneath the Moon by hardly greater than half that distance, and maybe a bit left, to search out Spica, the brightest star of Virgo.


■ Look to the decrease proper of the Moon, by about 6°, for Spica.

A number of instances farther to the higher left of the Moon shines brighter Arcturus.

And Vega, the Summer Star, the zero-magnitude equal of Arcturus, is now twinkling low within the northeast after dusk. Relying in your latitude. The farther north you’re the increased it is going to be. Should you’re within the latitudes of the southern US, you will have to attend till a bit later after darkish for it to seem.


■ Spot little Mars due west within the ft of Gemini after darkish. Discover it a bit lower than midway from Capella to Procyon and, for many of this week, slightly decrease. This night use a telescope (what with the intense moonlight!) to search for the open cluster M35 simply ½° to Mars’s left.

Mars glows on the trailing foot of Castor.

■ Full Moon (precise at 11:32 p.m. EDT). The Moon shines in Virgo, with Spica just a few levels to its decrease proper and brighter Arcturus a lot farther to its higher left.


■ This night M35 is ¾° beneath or decrease left of Mars. The moonlight stays vivid.


Now you have bought a dark-sky window of a couple of half hour between the top of twilight and moonrise (relying in your latitude) to see M35 freed from moonlight in all its glory. It is now 1.1° beneath Mars.

■ By midnight tonight the waning gibbous Moon is up within the southeast. Orange Antares is about 4° to its decrease proper. How a lot else of higher Scorpius are you able to see to the precise of the Moon?

By the daybreak of Wednesday the 29th, the Moon shines above Antares.


■ Face north simply after dusk, look very excessive, and you will find the Pointers, the top stars of the Large ’s bowl, on the meridian pointing towards Polaris straight down beneath. From the Tips that could Polaris is about three fists at arm’s size.


■ Arcturus is the brightest star excessive within the east these evenings. Spica shines decrease proper of it by about three fists at arm’s size. To the precise of Spica by half that distance is the distinctive four-star constellation of Corvus, the springtime Crow.


■ Regardless that Might has begun, wintry Sirius nonetheless twinkles very low within the west-southwest on the finish of twilight. It units quickly after. How for much longer into the spring can you retain Sirius in view? In different phrases, what will probably be its of “heliacal setting” as seen by you? The farther north you’re, the earlier it is gone for the season.


This Week’s Planet Roundup

Mercury and Venus start rising collectively from deep within the sundown. Reader Tony on northerly Vancouver Island (latitude about 48° N) known as Venus “straightforward” in 16x50 binoculars on the 17th. On Sunday the 25th Mercury is 1.2° to Venus’s higher proper, as proven on the high of this page. Venus is magnitude –3.9, and Mercury is unusually vivid at –1.6.

Begin trying as early as 15 minutes after sundown to catch their transient window of visibility between when the sky is just too vivid and the planets get too low and disappear within the extinction. The precise finest time after sundown will rely in your latitude (the farther north the higher) and the readability of the air.

Each planets are slightly increased and simpler every night, Mercury particularly. By Friday the 30th, Mercury stands 4.5° above Venus. Venus will preserve its brightness, however Mercury by then will probably be right down to magnitude –1.1.

Mars (magnitude +1.5, in Gemini on the really feel of the Castor determine) glows within the west after darkish. It is rather less than midway from Capella to Procyon and, for many of the week, a bit beneath that line. In a telescope it is a mere 5 arcseconds vast: only a tiny shimmering blob.

Jupiter and Saturn (at dim Capricornus) rise greater than an hour earlier than the primary mild of daybreak. As daybreak begins, spot them low within the southeast. Jupiter grabs the attention at magnitude –2.2. Saturn is 15° to Jupiter’s proper or higher proper, one fifteenth as vivid at magnitude +0.7.

Jupiter on April 13th. South right here is up. “I lastly had clear skies and higher seeing circumstances,” writes Christopher Go from his latitude of 10° N. “The Nice Pink Spot may be very darkish.” And word the way it curls a lot farther across the Pink Spot than in his picture 10 days earlier, beneath. The South Equatorial Belt following (proper of) the Pink Spot is unusually pale. The Equatorial Zone continues to point out complicated tan patterns throughout its northern two-thirds, and the south fringe of the North Equatorial Belt is darkish pink.
A picture by Go from April third. The darkish dot shouldn’t be a moon’s shadow however darkish Callisto itself, caught in a uncommon equatorial transit throughout Jupiter.

Uranus and Neptune are hidden within the glare of the Solar.

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 often known as UT, UTC, GMT, or Z time. To turn out to be extra skilled about time programs than 99% of the individuals you will ever meet, see our compact article Time and the Newbie Astronomer.

Need to turn out to be a greater astronomer? Be taught your manner across the constellations. They’re the important thing to finding the whole lot 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 masking the entire night sky, use the massive month-to-month map within the middle of every problem 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 essential customary 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 open air by pink 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 you realize your manner round, are the even bigger Interstellarum atlas (stars to magnitude 9.5) or Uranometria 2000.0 (stars to magnitude 9.75). And you should definitely learn use sky charts with a telescope.

You will additionally need a good deep-sky guidebook, comparable to Sky Atlas 2000.0 Companion by Robust and Sinnott, or the larger (and illustrated) Night Sky Observer’s Guide by Kepple and Sanner.

Can a computerized telescope exchange charts? Not for freshmen, I do not assume, and never on mounts and tripods which might 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 talents to search out issues within the sky and understanding how the sky works. This information 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, 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 larger 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 could be rather more deadly in methods it was by no means earlier than.”
            — Carl Sagan, 1996

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


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