This Week’s Sky at a Glance, October 22 – 30

We nonetheless cannot look away. Nova Cassiopeiae 2021 had swelled again as much as magnitude 7.0 on October twentieth. This is at least its tenth rebound because it exploded final March. Charts and comparison stars.


■ The waning gibbous Moon shines within the east after darkish this night. You might have binoculars to pick the Pleiades few levels to its left or higher left, as proven beneath. Much simpler is vibrant Capella many instances farther left of the Moon.

As night advances, Aldebaran comes up beneath or decrease left of the Moon. By midnight, Orion is clearing the japanese horizon far beneath all of them.


■ Tonight the waning Moon shines close to Aldebaran, as proven beneath.

Every October, the Moon commits its month-to-month meetup with the Pleiades and Aldebaran whereas waning gibbous. The nerve.

■ This is the time of year when the Big Dipper lies down horizontal low within the north-northwest after darkish. How low? The farther south you’re, the decrease. Seen from 40° north (New York, Denver, Madrid) even its backside stars twinkle almost ten levels excessive. But at Miami (26° N) your complete Dipper skims alongside out of sight just under the northern horizon.


■ This can be the time of year when W-shaped Cassiopeia stands on finish (its fainter finish) excessive within the north-northeast in early night — and when, between Cassiopeia and the Big Dipper, the dim Little Dipper extends leftward from Polaris.


The Ghost of Summer Suns. Halloween is approaching, and which means Arcturus, the star glowing low within the west-northwest in twilight, is taking over its position as “the Ghost of Summer Suns.” For a number of evenings centered on October twenty fifth each year, Arcturus occupies a particular place above your native panorama. It carefully marks the spot the place the Sun stood at the identical time, by the clock, throughout scorching June and July — in broad daylight, in fact!

So, as Halloween approaches each year, you may see Arcturus because the chilly ghost of the departed summer time Sun.


■ This week Jupiter crosses the meridian (is highest due south) round 8:00 daylight-saving time, relying how far east or west you reside in your time zone. And this month when Jupiter crosses the meridian, so does the nostril star of upside-down Pegasus: Enif, aka Epsilon Pegasi. “Enif” is from the Arabic for nostril, a designation adopted from the Greeks’ tackle Pegasus.

At magnitude 2.4, Enif is straightforward to identify 25° above Jupiter. That’s about 2½ fists at arm’s size. Sharp eyes, or binoculars, reveal that it is yellow-orange; it is a Okay3 supergiant.

Enif is your start line for locating the effective fall globular cluster M15, positioned 5° to the star’s northwest (higher proper these evenings). At sixth magnitude M15 is inside binocular vary as a tiny glowball, and a 6-inch telescope might start to resolve a few of its sugarpile starspecks. Use the finder chart with Matt Wedel’s Binocular Highlight column within the (*30*), web page 43.


■ Jupiter’s interior moon Io enters onto the face of Jupiter’s disk at 9:20 p.m. EDT, adopted by Io’s tiny black shadow at 10:37 p.m. EDT. Each takes about 1 hour 40 minutes to cross the planet.

Meanwhile on Jupiter itself, the Great Red Spot ought to cross Jupiter’s central meridian round 11:24 p.m. EDT (8:24 p.m. PDT). The Red Spot is in effective place for a good 50 minutes earlier than and after its transits. A light-weight blue or green filter at the eyepiece helps to disclose it.

■ Got a actually massive scope and a dark-sky location? Now that the Moon is gone from the early night, carry your deep-sky atlas and take a look at “The Odd World of Peculiar Galaxies” within the (*30*) beginning on web page 57, with photographs and visible drawings. The ten featured galaxies are magnitudes 12 to 14.


■ Last-quarter Moon (precisely so at 4:05 p.m. Eastern Daylight Time). The half-lit Moon rises round midnight, in Cancer far beneath Castor and Pollux. Once the Moon is properly up, the night time is late sufficient that you just’re getting a effective preview of the winter night sky. Spot Procyon two or three fists at arm’s size proper of the Moon, and sensible Sirius the identical distance proper of Procyon. High over Sirius is Orion; excessive over Orion is Taurus with Aldebaran, the Hyades, and the Pleiades.

The later you look, the steeper the Jupiter-Saturn line tilts. And, by late night you may discover the binocular double stars Alpha and Beta Capricorni virtually on to Saturn’s proper, reasonably than higher proper of it as in early night.


■ Look for vibrant Capella glowing low within the northeast these evenings. Look for the Pleiades cluster about three fists at arm’s size to Capella’s proper. These harbingers of the chilly months rise greater as night grows late and look ahead to Aldebaran arising beneath the Pleiades.

Upper proper of Capella, and higher left of the Pleiades, the stars of Perseus lie astride the Milky Way.


■ Spot vibrant Altair excessive within the southwest quickly after darkish. Brighter Vega is way to its proper.

Above Altair lurk two distinctive little constellations: Delphinus the Dolphin, hardly greater than a fist at arm’s size to Altair’s higher left, and smaller, fainter Sagitta the Arrow, barely much less far to Altair’s higher proper. Light air pollution too vibrant? Use binoculars!


This Week’s Planet Roundup

Mercury, at the neck of stick-figure Virgo, is having its finest morning apparition of the year. Look for it low above the horizon in early daybreak 60 to 40 minutes earlier than your dawn time, simply a little south of due east. It’s brightening daily: from magnitude –0.2 on the morning of October twenty second to –0.8 on the twenty ninth.

Mars stays out of sight behind the glare of the Sun.

Venus, sensible at magnitude –4.4, shines in southwest throughout twilight, crossing the ft of Ophiuchus between Antares at its decrease proper and the Sagittarius Teapot at its higher left. Venus now stays up about 45 minutes after twilight’s finish. It will proceed to get greater and brighter into early December.

Jupiter and Saturn proceed to shine within the south throughout night, 15° aside on reverse sides of Capricornus. Jupiter is the brilliant one at magnitude –2.5. Saturn, to its proper or decrease proper, is fainter at magazine +0.6.

In twilight they’re virtually the identical top, simply starting to tilt. As night advances they tilt ever extra steeply as they transfer westward. Saturn units round midnight daylight-saving time, adopted by Jupiter about an hour later.

Look 23° (two fists at arm’s size) decrease left of Jupiter for Fomalhaut, magnitude +1.2.

Here’s a beginner’s telescopic guide to Jupiter.

Jupiter on October sixth, imaged by S&T‘s Sean Walker with a 12-inch reflector in New Hampshire. North is up. “We were treated to some excellent seeing conditions.” he writes. “I spent hours shooting and observing the planet, watching the GRS transit, as well as the dark barges in the NEB, and the series of white ovals south of the SEB. It was a magical night of observing — I was seeing the first diffraction ring around Io and Europa; don’t think I can ever recall seeing that before. Wish I could have shared it with others.”

Uranus (magnitude 5.7, in southern Aries) is properly up within the east by 9 or 10 p.m.

Neptune (magnitude 7.8, at the Aquarius-Pisces border) is already properly up within the southeast at the top of twilight.

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 also called UT, UTC, GMT, or Z time. To turn out to be extra skilled about time programs than 99% of the individuals you may ever meet, see our compact article Time and the Amateur Astronomer.

Want to turn out to be a higher astronomer? Learn your way across the constellations. They’re the important thing to finding all the pieces fainter and deeper to hunt with binoculars or a telescope.

This is an outside nature pastime. For an easy-to-use constellation information overlaying the entire night sky, use the large month-to-month map within the heart of every situation of Sky & Telescope, the journal of the American Astronomical Society.

Once you get a telescope, to place it to good use you may want a detailed, large-scale 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 tons of of telescopic galaxies, star clusters, and nebulae amongst them. Shown right here is the Jumbo Edition, which is in laborious 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; almost 3 times as many. The subsequent up, as soon as you realize 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 a Star Chart with a Telescope.

You’ll additionally need a good deep-sky guidebook, comparable to the large Night Sky Observer’s Guide by Kepple and Sanner.

Can a computerized telescope change charts? Not for newbies, I do not suppose, and never on mounts and tripods which can be 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 underneath 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’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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