■ In twilight this evening, look for the thin crescent Moon far to the lower right of Venus as shown below. As the sky gets darker watch for Aldebaran to appear, and then, much fainter, the Pleiades.

The waxing crescent Moon passing the Pleiades and then Venus, April 21-23, 2023
The waxing crescent Moon steps up in the western twilight past the delicate Pleiades (use binoculars), then past power-shining Venus. Mercury, though plotted here, is almost hopelessly low and faint.


■ Venus, the crescent Moon, and Aldebaran form a nearly isosceles triangle in the west as darkness falls, as shown above. The long sides of the triangle are both 8° long (for much of the Americas).


■ Now the thickening Moon shines over Venus during and after dusk, as shown above.

■ These spring evenings, the long, dim sea serpent Hydra snakes far across the southern sky. Find Hydra's head, a rather dim asterism about the width of your thumb at arm's length, high in the southwest. It's lower right of Regulus by about two fists at arm's length. Also, a line from Castor through Pollux points to it about 2½ fists away.

Hydra's tail stretches all the way to Libra, now rising low in the southeast. Hydra's star pattern, from forehead to tail-tip, is 95° long. Hydra is by far the longest constellation and is also the largest in area.


■ After dark, look high in the west for Pollux and Castor lined up almost horizontally (depending on your latitude). Mars, looking similar, is a third dot down below them.

Pollux and Castor form the top of the enormous Arch of Spring. To their lower left is Procyon, the left end of the Arch. Farther to their lower right is the other end, formed by Menkalinan (Beta Aurigae) and then brilliant Capella. Venus shines under its Arch's right side. The whole thing sinks in the west through the evening.


■ The thick waxing crescent Moon pairs with Mars in the center of Gemini this evening, as shown below.

The waxing Moon passing Mars, Pollux, and Castor, April 24-26, 2023
Mars and Pollux remain very nearly alike this week. But on Tuesday the 25th, will Mars seem dimmer on account of the Moon being close by? On the 26th, will Pollux seem dimmer for the same reason?


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

Arcturus forms the pointy end of a long, narrow kite-skaped 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. The kite is 23° long, about two fist-widths at arm's length.

■ Now turn northwest. The brightest star there is Capella, essentially the equal of Arcturus in brightness. They stand at exactly the same height above your horizon in late twilight, depending on your latitude.

■ And Vega, the Summer Star, the other zero-magnitude equal of Arcturus and Capella, is now twinkling low in the northeast after nightfall. . . depending on your latitude. The farther north you are the higher it will be. If you're in the latitudes of the southern US, you'll have to wait until a bit later after dark for it to appear.


■ First-quarter Moon (exact at 5:20 p.m. EDT), in dim Cancer. As the stars come out this evening, look for Regulus about two fists at arm's length to the Moon's left, and Pollux and Castor not quite as far to the Moon's right.

As the night grows later, this straight line of three tilts clockwise.


■ The Moon, a day past first quarter, shines high toward the south-southwest after dark. It's hanging off the crook of the Leo Sickle, which is nearly upright.


■ Now the Moon shines just behind (left of) the Sickle's handle. The Moon is roughly equidistant from Regulus and Algieba, the Sickle's two brightest stars.


■ Face north just after nightfall, look very high, and you'll find the Pointers, the end stars of the Big Dipper's bowl, on the meridian pointing toward Polaris straight down below. From the Pointers to Polaris is about three fists at arm's length.


This Week's Planet Roundup

Mercury is lost in the sunset.

Venus (magnitude –4.1, in eastern Taurus) is the brilliant "Evening Star" in the west during and after dusk. It doesn't set until two hours after full dark. Night by night, watch as the horntip stars of Taurus slide down toward it. Venus will pass between them on Monday May 1st.

In a telescope Venus is a dazzling little gibbous globe (69% sunlit) 16 or 17 arcseconds in diameter. It's gradually enlarging while waning in phase. It'll be 50% lit by late May, and will be a bigger, dramatic crescent from mid-June through mid-July.

BTW, forget the Face on Mars. Now there's the Monkey on Venus. With 85,000 volcanos newly mapped on Venus, it had to happen. Wave hi to the monkey up there beyond the twilight.1

Mars is crossing central Gemini this week. Look for it high in the west in early evening, lower later. It's upper left of Venus by about three fists at arm's length, and it's below Pollux and Castor.

Mars has faded to magnitude +1.3, the barest trace fainter than Pollux. Mars shows a slightly deeper orange tint. Mars is drawing closer to Pollux and Castor and will line up with them, to their left, on the evening of May 16th.

Because Mars is nearly on the far side of its orbit from us, in a telescope it's a tiny blob just 5½ arcseconds wide.

Jupiter is out of sight, very deep in the glow of sunrise.

Saturn (magnitude +1.0, in dim Aquarius) is low in the east-southeast in early dawn.

Faint Uranus and Neptune are out of sight, very low in the evening and morning twilight respectively.

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 sometimes called 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 be sure to 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 a computerized telescope replace charts? Not for beginners, I don't think, and not on mounts and tripods that are less than top-quality mechanically. 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."

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

1. Of course there's no monkey up there to say hi to, so don't write me about it! The Venus volcano photo is an example of pareidolia: the overinterpretation of a sensory input to create the actual experience of seeing, for instance, grotesque faces, figures, and animals in clouds or tree trunks. Or stick-figure people and animals in the stars. Although these things are not actually real, the experiences of them are entirely real. Endless confusion in the world arises from people not grasping how fully both types of experience, the factual and the creative, arise from our same neural process of reality-determination and consciousness formation. See the beholder's share in art theory (especially for how impressionism works). For the currently favored neural mechanism responsible for the formation of all conscious perceptions and ideas, real or hallucinated, see Bayesian brain. Recent developments; see the second section.

End of Philosophy 101. Go skywatch, and say hi to your pareidoliated monkey who isn't there but is.


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April 21, 2023 at 11:00 pm

On to the next solar eclipse!

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April 21, 2023 at 11:12 pm

Are you going to try to see Venus in the daytime during October's annular eclipse?

It will be near Regulus, so you can track that star as it crosses the sky over thecnext few nights to get an idea of Venus's path on "A-Day". Venus will only be about 2 months past greatest brilliancy, and the darker skies near mid eclipse might help it stand out more.

To make it even easier, the Sun will be near Spica during the eclipse. Spica is just a week or so past opposition, so it's a good proxy for the Sun's positions during the Eclipse. Find the local eclipse times for your location add 12 hours, and see where Spica (standing in for the Sun) and Regulus (standing in for Venus) are located. You can try and line up Regulus with landmarks like trees or buildings to get a better idea of where to position yourself, and where to look for Venus, during the eclipse.

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April 22, 2023 at 12:02 am

I just checked the sky charts at For Los Angeles, max eclipse occurs at 9:24am. Tonight's sky matched the eclipse sky at 9pm, about 30 mins earlier than the 12 hours that I mentioned, but this makes sense since the "6 months to go!"date was last week, and the stars' configurations occur 4 minutes earlier each night.

Anyhow, for Los Angeles, Regulus will almost on the meridian at mid-eclipse.

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April 23, 2023 at 9:59 pm

Some lovely viewing tonight. Observed 2000-2100 EDT. Sunset 1951 EDT. First Quarter Moon 27-April-2023 2120 UT. Lovely evening after sunset viewing the waxing crescent Moon with Venus in Taurus. Both separated by about 5-degrees according to Stellarium 23.1. I used my 90-mm refractor with Orion Sirius 25-mm plossl for 40x views. I used a #17 polarizer filter to help with the brightness and glare of Venus and the Moon. Earthshine was lovely tonight. Many craters were distinct along the terminator line on the Moon. The Picard crater in Mare Crisium easy to see (Virtual Moon Atlas). Venus was nearly half-moon shape and about 69% illuminated with a bit more than 16 arcsecond angular size according to Stellarium. Near the Moon, less than 30-arcminutes separation were some 8th magnitude stars apparent in the FOV. HIP24431 and TYC1850-58-1. HIP24431 about 578 light-years distance, Virtual Moon Atlas reported the Moon about 390465 km. Venus tonight near 1.033 au. The Moon’s angular size is 30.60 arcminutes. The eyepiece true FOV close to 1.3-degrees or 78 arcminutes in my telescope. Mostly clear skies tonight, winds 320/14 knots gusting 21 knots, temperature 10C. Some owls were hooting and a deer passing near my position snorted at me indicating dislike that I was out in the pasture and fields. As the sky darkened after sunset, the earthshine on the Moon was lovely.

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mary beth

April 29, 2023 at 11:22 am

Hope we get the upcoming week’s column posted soon…..really enjoy/utilize this page!

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mary beth

April 30, 2023 at 8:12 pm


At nightfall, the moon, Arcturus and Spica form a beautiful triangle that traverses the sky until the moon sets about 4:30 a,m.

Both Rigel and the Pleiades are setting shortly after dark. Soon you’ll need an unobstructed western horizon to watch them, so enjoy while you can.

Today, the first day of May traditionally marks the midway point between the Spring equinox and the Summer solstice. Celebrated as Beltane (a.k.a Bright Fire), St. Walpurga Day in Europe, with all night bonfires and sparkling wine, I recommend stargazing if you are outside all night!

Ok folks, since we don’t have a new column yet this is the best I can do!

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Monica Young

May 1, 2023 at 4:00 pm

Hi mary beth, new column is up over here!

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mary beth

May 1, 2023 at 4:48 pm

Thanks Monica! Love this column!

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