■ Zero-magnitude Capella high overhead these evenings, and equally bright Rigel in Orion's foot, have almost the same right ascension. This means they cross your sky’s meridian at almost exactly the same time: around 9 p.m. now, depending on how far east or west you live in your time zone. (Capella goes exactly through your zenith if you're at latitude 46° north: Portland, Oregon; Portland, Maine; Montreal; central France; Odesa.) So, whenever Capella passes its very highest for you, Rigel marks true south over your landscape, and vice versa.

■ Catch Venus, Mercury, and Antares low in the early dawn Saturday morning, as shown below.

Venus and Mercury low in the dawn, Jan. 20, 2024
Venus and Mercury shine low in the dawn. The visibility of the fainter objects in bright twilight is exaggerated here. Binoculars help, but even so, Mars may be too low.


■ Early this evening look to the right of the bright gibbous Moon, by about three finger-widths at arm's length, for the delicate Pleiades cluster. Binoculars help pull out the Pleiades through the moonlight.

Almost a fist below or lower left of the Moon is orange Aldebaran, amid the fainter, sparser Hyades.

■ Sirius twinkles brightly below Orion in the southeast these evenings. Around 8 or 9 p.m., depending on your location, Sirius shines precisely below fiery Betelgeuse in Orion's shoulder. How accurately can you time this event for your location, perhaps judging against the vertical edge of a building? Of the two, Sirius leads the race early in the evening; Betelgeuse leads later.


■ Now the gibbous Moon high overhead shines partway between Aldebaran and brighter Capella.

■ Jupiter's moon Io crosses onto Jupiter's face at 6:50 p.m. EST. Then it exits from Jupiter's opposite edge at 8:59 p.m. EST. The tiny black shadow of Io follows behind across Jupiter's face from 8:10 to 10:19 p.m. EST.

Meanwhile, Jupiter's Great Red Spot crosses Jupiter's central meridian around 7:32 p.m. EST.


■ The gibbous Moon shines in a starry area of the winter sky. Face east in early evening. Upper left of the Moon sparkles bright Capella. A little farther upper right of the Moon is orange Aldebaran. Lower left of the Moon are Castor and Pollux. Lower right of the Moon is orange Betelgeuse, in the shoulder of Orion.


■ The big Northern Cross in Cygnus, topped by Deneb, is nearly upright in the west-northwest right after dusk. Another hour or so and it's planted on the horizon. How straight up it stands depends on your latitude.


■ L0ok above the Moon this evening, by two or three finger-widths at arm's length, for Pollux. Above Pollux by about three fingers is Castor.


■ Full Moon (exactly full at 12:54 p.m.). The Moon this evening forms a long, not quite straight line with Procyon, the Little Dog Star off to its right, and Sirius, the Dog Star proper, a similar distance to Procyon's right or lower right. The line is about five fists end to end.

■ It's still only January, but Leo the springtime Lion is already poking up in the east after dinnertime. Leo hosts the bright Moon for the next couple of nights, as shown below.

Moon and Regulus rising, Jan. 25-27, 2024


■ As soon as it's fully dark, spot the equilateral Winter Triangle in the southeast. Sirius is its brightest and lowest star. Betelgeuse stands above Sirius by about two fists at arm's length. To the left of their midpoint is Procyon.

Can you discern their colors? Sirius (spectral type A0) is cold white, Betelgeuse (M2) is yellow-orange, and Procyon (F5) is a very pale yellowish white.

■ Mercury and fainter Mars have a very difficult conjunction just above the southeast horizon as Saturday's dawn grows bright, as shown below. You'll need an open horizon and optical aid, maybe powerful aid.

Mercury-Mars conjunction very low in the dawn, January 27, 2024.
Venus guides the way to the Mercury-Mars conjunction. The visibility of faint objects low in the brightening dawn is exaggerated here.


■ The biggest well-known asterism (informal star pattern) is the Winter Hexagon. It now fills the sky toward the east and south these evenings.

Start with brilliant Sirius at its bottom. Going clockwise from there, march up through Procyon, Pollux and Castor, Menkalinan and Capella on high, over and down to Aldebaran, then to Rigel in Orion's foot, and back to Sirius. Betelgeuse shines inside the Hexagon, off center.

The Hexagon is somewhat distended. But if you draw a line through its middle from Capella down to Sirius, the "Hexagon" is fairly symmetric with respect to that long axis.

Take the line from Aldebaran to Capella, turn it to go from Aldebaran to Betelgeuse instead, and the Winter Hexagon becomes the Heavenly G. The Masons have something to say about that.


■ After dark now the Great Square of Pegasus is sinking low in the west, tipped onto one corner. Meanwhile, the Big Dipper is creeping up in the north-northeast, tipped up on its handle.

This Week's Planet Roundup

Mercury, magnitude –0.2, remains 11° or 12° lower left of bright Venus low in the dawn this week, as shown at the top of this page. The time window is becoming very narrow between when Mercury rises and dawn grows too bright for it. Good luck.

Venus, magnitude –4.0, shines in the southeast during dawn, getting lower every week. Look for orange Antares, magnitude +1.0, upper right of Venus by 19° on the morning of January 21st. A week later, they're 27° apart.

Mars, a mere magnitude +1.3, is a very difficult catch near Mercury late this week even with binoculars or a telescope. The two are in conjunction only ¼° apart on the morning of January 27th, with Mars below Mercury as shown above.

Jupiter, magnitude –2.4 in Aries, is the bright white dot very high in the south at nightfall, and lower in the southwest later. It sets around midnight or 1 a.m. In a telescope Jupiter has shrunk to only 40 arcseconds wide.

Jupiter with Great Red Spot, Jan. 17, 2024
Jupiter's Great Red Spot side on January 17th, imaged by Christopher Go. South here is up. Notice the difference in the darkness of the wide South Equatorial Belt on either side of the Red Spot. Go writes that the new hook-like feature just east of the Great Red Spot (to its right here) "is very prominent. This feature seems to be a barrier that prevents the wake of the GRS from spilling to the other side of the SEB."

We've adjusted the contrast to approximate Jupiter's visual appearance. To get a better idea of Jupiter as seen in a telescope at high power, stand far back from your screen and maybe squint a bit.

Saturn, magnitude +1.0 in Aquarius, sinks lower in the west-southwest during and after dusk. It sets around 7 or 8 p.m.

Uranus, magnitude 5.7 in Aries, hides in the darkness 12° east of Jupiter in early evening. In a telescope at high power Uranus is a tiny but distinctly nonstellar ball, 3.8 arcseconds in diameter. Locate and identify it using the finder charts in the November Sky & Telescope, pages 48-49.

Neptune, fainter at magnitude 7.9, is getting low after dark, 21° east (upper left) of Saturn.

All descriptions that relate to your horizon — including the words up, down, right, and left — are written for the world's mid-northern latitudes. Descriptions and graphics that also depend on longitude (mainly Moon positions) are for North America.

Eastern Standard Time (EST) is Universal Time minus 5 hours. UT is also known as UTC, GMT, or Z time.

Want to become a better astronomer? Learn your way around the constellations. They're the key to locating everything fainter and deeper to hunt with binoculars or a telescope.

This is an outdoor nature hobby. For a more detailed constellation guide covering the whole evening sky, use the big monthly map in the center of each issue of Sky & Telescope, the essential magazine of astronomy.

Once you get a telescope, to put it to good use you'll need a much more detailed, large-scale sky atlas (set of charts). The basic standard is the Pocket Sky Atlas (in either the original or Jumbo Edition), which shows all stars to magnitude 7.6.

Pocket Sky Atlas cover, Jumbo edition
The Pocket Sky Atlas plots 30,796 stars to magnitude 7.6, and hundreds of telescopic galaxies, star clusters, and nebulae among them. Shown here is the Jumbo Edition, which is in hard covers and enlarged for easier reading outdoors by red flashlight. Sample charts. More about the current editions.

Next up is the larger and deeper Sky Atlas 2000.0, plotting stars to magnitude 8.5; nearly three times as many. The next up, once you know your way around, are the even larger Interstellarum atlas (stars to magnitude 9.5) or Uranometria 2000.0 (stars to mag 9.75). And read How to Use a Star Chart with a Telescope. It applies just as much to charts on your phone or tablet as to charts on paper.

You'll also want a good deep-sky guidebook. A beloved old classic is the three-volume Burnham's Celestial Handbook. An impressive more modern one is the big Night Sky Observer's Guide set (2+ volumes) by Kepple and Sanner.

Can computerized telescopes replace charts? Not for beginners I don't think, especially not on mounts and tripods that are less than top-quality mechanically. Unless, that is, you prefer spending your time getting finicky technology to work rather than learning the sky. And as Terence Dickinson and Alan Dyer say in 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."

If you do get a computerized scope, make sure the drives can be disengaged so you can swing it around and point it readily by hand rather than only slowly by the electric motors.

However, finding a faint telescopic object the old-fashioned way with charts isn't simple either. Learn the tricks at How to Use a Star Chart with a Telescope

Audio sky tour. Out under the evening sky with your
earbuds in place, listen to Kelly Beatty's monthly
podcast tour of the naked-eye 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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