This Week's Sky at a Glance, April 10 – 19

Well that didn't happen. The sungrazing Comet MAPS (C/2026 A1) disappeared from SOHO spacecraft images after its perihelion very close to the Sun on April 4th, leaving nothing to emerge above our twilight horizon. Darn.

---

---

FRIDAY, APRIL 10

■ At this time of year, the two Dog Stars stand vertically aligned in late twilight. Look southwest. Brilliant Sirius in Canis Major is below, and Procyon in Canis Minor is two fists at arm's length above it. (Don't be distracted by brighter Jupiter higher up.)

Look to the right of their midpoint for orange Betelgeuse, the third star of the equilateral Winter Triangle. It marks Orion's shoulder.

SATURDAY, APRIL 11

■ Find Procyon again above brilliant Sirius in the southwest after dark. Look upper left of Procyon by 15° (about a fist and a half at arm's length) for the dim head of Hydra, the enormous Sea Serpent. His head is a group of 3rd- and 4th- magnitude stars about the size of your thumb at arm's length.

About a fist and a half lower left of Hydra's head shines Alphard, the serpent's 2nd-magnitude orange heart. The rest of Hydra zigzags (faintly) from Alphard all the way down to the southeast horizon.

Hydra's heads makes a roughly equilateral triangle with Regulus and Alphard.

SUNDAY, APRIL 12

■ Arcturus shines brightly in the east these evenings. The Big Dipper, high in the northeast, points its curving handle lower-right down toward it.

Arcturus forms the pointy end of a long, narrow kite asterism formed by the brightest stars of Boötes, the Cowherd. The kite is currently lying on its side to Arcturus's left. The head of the kite, at the far left, is bent slightly upward as shown below. The kite is 23° long: about two fists at arm's length:

MONDAY, APRIL 13

■ Jupiter's moon Europa crosses Jupiter's face from 9:11 p.m. to 12:00 midnight EDT. Watch Europa merge into Jupiter's eastern limb at the beginning of this transit and bud off from the western limb as it exits. Following well behind is Europa's little black shadow, crossing Jupiter's face from 11:42 p.m. to 2:32 a.m. EDT.

Change these times to your own time zone. Wherever you are, Jupiter gets too low in the west by about midnight or 1 a.m. local daylight-saving time.

TUESDAY, APRIL 14

■ This is the time of year when the bowl of the Little Dipper extends straight to the right of Polaris shortly after dark. Most of the Little Dipper is dim, but Kochab at the lip of its bowl is the equal of Polaris; both are 2nd magnitude. Spot Kochab 16° (about a fist and a half at arm's length) to Polaris's right.

A little below it is Pherkad, 3rd magnitude. High above these end-stars of the Little Dipper's bowl, you'll find the end-stars of the Big Dipper's bowl.

■ A tough dawn challenge: If you have access to an almost perfectly low, flat horizon view due east, the thin waning crescent Moon will rise there early in Wednesday's dawn. By a half hour before sunrise the Moon will be about 6° above the true horizon, though by then the sky will be getting seriously bright.

Below the Moon are four planets: Mercury, Mars, Saturn, and Neptune. "But only the first two are high enough and bright enough to be visible," writes Gary Seronik in the April Sky & Telescope, page 46. Bring binoculars!

See the illustration above. Below the Moon by almost 4° is Mercury, magnitude 0 but severely dimmed by atmospheric extinction. Even tougher will be Mars, magnitude +1.2 (before extinction). Look for it 4° left of Mercury. Writes Gary, "Don't be disappointed if the Moon is the only one of the three you catch."

WEDNESDAY, APRIL 15

■ Bright Arcturus climbs high in the east these evenings. Equally bright Capella is descending high in the northwest. They stand at exactly the same height above your horizon at some moment between about 9:00 and 10:30 p.m. daylight-saving time — depending mostly on how far east or west you live in your time zone, but also to some extent on your latitude.

How accurately can you time this? Like everything constellation-related, it happens 4 minutes earlier each night.

Your timing, along with judicious use of the stars' celestial coordinates, a nautical almanac, and some seriously not-simple paperwork, can indicate your latitude and longitude. This is the kind of thing sailors once did using sextants. Or, try a modern version of it backwards! Using a planetarium program set for your known location, set the date and run the time back and forth until Capella and Vega stand at the same altitude. Read off the time. How well or poorly did your naked-eye estimate match this time? Can you get better with practice?

THURSDAY, APRIL 16

■ Back to Arcturus, that brightest star in the east. About three fists to its lower right look for Spica, less bright. To the right of Spica by half that distance is the distinctive four-star pattern of Corvus, the springtime Crow.

The Crow's constellation stick-figure, as Sky & Telescope connects the star dots, is eyeing Spica as if to steal it from the lower hand of the Virgo stick figure. Appropriate; Virgo is supposed to be a young woman sowing grain from her hand onto springtime fields.

FRIDAY, APRIL 17

■ Vega, the Summer Star, already twinkles low in the northeast these spring evenings. It's five or six fists at arm's length lower left from Arcturus and equally bright; both are magnitude 0.

How high or low will Vega shine for you soon after dark? That will depend on your latitude. The farther north you are, the earlier with respect to twilight Vega rises. If you live in the latitudes of the southern U.S., you'll have to wait until somewhat later for Vega to make its appearance.

■ New Moon (at 7:52 a.m. EDT on this date).

SATURDAY, APRIL 18

■ Low in the west-northwest in twilight this evening, a hair-thin crescent Moon, just 1½ days old, hangs 4° or 5° to the right or lower right of Venus. Binoculars should give a lovely view of earthshine softly illuminating the Moon's whole night landscape. Venus and the Moon both set just after complete dark.

SUNDAY, APRIL 19

■ Now the crescent Moon is 2½ days old and about 11° above Venus. Between them as twilight darkens, watch for the Pleiades to come out. As shown above.

Venus will pass by the Pleiades on April the 23rd and 24th, missing them by 3°.

■ Saturn is now emerging from deep in the sunrise glare to join Mercury and Mars as possibly visible with optical aid extremely low as dawn gets bright. On Monday morning the 20th the three planets form a tight lineup, as shown below. Good luck.

---

This Week's Planet Roundup

Mercury, Mars, Saturn and Neptune are very low in the glow of sunrise. You may have a slim chance at Mercury and even Mars this week. On Wednesday morning the thin crescent Moon guides your way, as shown under April 14 above.

Venus, bright at magnitude –3.9, gleams low in the western evening twilight, a bit higher each week. Fifty minutes after sunset, you'll find it about a fist at arm's length (10°) above horizontal. Venus sets soon after the end of twilight.

Jupiter, magnitude –2.1, is second brightest only to Venus. It shines very high toward the west at nightfall. Jupiter swings lower through the evening. It sets around 2 a.m. daylight-saving time on the west-northwest horizon.

In a telescope Jupiter is down to 38 arcseconds wide. It's shrinking and fading as Earth pulls farther ahead of it in our faster orbit around the Sun.

Uranus (magnitude 5.8 in Taurus, 4° south of the Pleiades) is still some 16° high in the west right after the end of twilight. At high power in a telescope it's a tiny but non-stellar dot, 3.5 arcseconds wide. You'll need a detailed finder chart to identify it among similar-looking faint stars.

---

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 Daylight Time (EDT) is Universal Time minus 4 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.

For the attitude every amateur astronomer needs, read Jennifer Willis's Modest Expectations Give Rise to Delight.

Once you get a telescope, to put it to good use you'll want 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. Both show all 30,000 stars to magnitude 7.6, and 1,500 deep-sky targets — star clusters, nebulae, and galaxies — to search out among them.

Next up is the larger and deeper Sky Atlas 2000.0, plotting stars to magnitude 8.5; nearly three times as many, as well as many more deep-sky objects. It's currently out of print, but maybe you can find one used.

The next up, once you know your way around well, are the even larger Interstellarum Deep-Sky Atlas (with 201,000+ stars to magnitude 9.5 and 14,000 deep-sky objects selected to be detectable by eye in very large amateur telescopes), and Uranometria 2000.0 (332,000 stars to mag 9.75, and 10,300 deep-sky objects).

For the necessary tricks, read How to Use a Star Chart with a Telescope. It applies just as much to electronic charts on your phone or tablet — which many observers find handier and more versatile, if sometimes less well designed and contextualized, than charts on paper.

You'll also want a good deep-sky guidebook. A beloved old classic is the three-volume Burnham's Celestial Handbook. It was my bedside reading for years. An impressive more modern one is the big Night Sky Observer's Guide set (2+ volumes) by Kepple and Sanner. The pinnacle for total astro-geeks is the new Annals of the Deep Sky series, currently at 11 volumes as it works its way forward through the constellations alphabetically. So far it's up to H.

Can computerized telescopes replace charts? Well, I used to say this:

"Not for beginners, I don't think, unless you prefer spending your time getting finicky technology to work rather than learning how to explore through the sky yourself. 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 and a curious mind.' Without these, 'the sky never becomes a friendly place.' "

But, things do change. The technology has continued to improve and become more user-friendly — particularly with "plate solving" software that can now recognize any star field to determine exactly where the telescope is pointed — finally bypassing all aiming imperfections in the mount, tripod, gears, bearings and other mechanics, or in the user's skill in setting up.

The latest revolution is the rise of small, imaging-only "smartscopes." These take advantage of not only today's pointing technology, but also the vastly better capabilities of imaging chips and image processing compared to the human retina and visual cortex. The most sophisticated image stacking and processing can come built right in. The result is decent deep-sky imaging from shockingly small, low-priced units. The image may be viewable on your phone or computer as it builds up in real time. Some can directly enable contributions to citizen-science projects.

Smartscopes are changing the hobby at the entry level. For more on this revolution see Richard Wright's "The Rise of the Smart Telescopes" in the November 2025 Sky & Telescope. And read the magazine's review of this especially small one.

If you get a larger, more conventional computerized scope that you can look through, make sure that its drives can be disengaged so you can swing it around and point it readily by hand when you want to, rather than only slowly by the electric motors (which eat batteries).

---

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; and whatever may be our wishes, our inclinations, or the dictates of our passion, they cannot alter the state of facts and evidence."
            — John Adams, 1770

"Truly, whoever can make you believe absurdities can make you commit atrocities."
            — Voltaire, 1765

---

---