This Week's Sky at a Glance, June 19 – 28

FRIDAY, JUNE 19

The Moon is a thick crescent in the west, left of Regulus. A telescope this evening shows the Moon's terminator crossing, from north to south, Mare Frigoris, Lacus Somniorum, Mare Tranquillitatis, and Mare Nectaris, as shown below.

On the south edge of Nectaris is the standout flooded crater Fracastorius, always a landmark when the Moon is near this phase. Just south of Fracastorius, shadows fill the similar-sized craters Piccolomini and the more ragged Stiborius.

SATURDAY, JUNE 20

■ On this final evening of spring, look very low in the north-northwest in late twilight for wintry Capella twinkling far out of season. The farther north you are the longer Capella hangs in. For the South it's well and truly gone. But if you're as far north as Montreal or either of the Portlands (Oregon or Maine), Capella is actually circumpolar.

SUNDAY, JUNE 21

■ Today is the longest day of the year for the Northern Hemisphere, and the official start of summer. The summer solstice comes at 4:25 a.m. EDT, when the Sun ends its northward journey for the season and begins its six-month return south.

The Sun today crosses your sky the highest it ever can (if you're in the North Temperate Zone). So today your shadow becomes the shortest it can ever be at your location. This happens at local apparent noon (noon "solar time"), which at your location is probably rather far removed from noon by the clock.

This is also the day when the Sun rises and sets farthest north on your horizon. Though the difference in the rise and set points is extremely slight for several days before and after.

■ First-quarter Moon (exact at 5:55 p.m. EDT). After dusk, look for 1st-magnitude Spica about two fists to the Moon's left or upper left, and 2nd-magnitude Denebola, tail star of Leo, the same distance to the Moon's upper right. Lower left of the Moon, Corvus is on its way to setting.

The Moon's straight terminator has now unveiled all of Tranquillitatis and Serenitatis.

MONDAY, JUNE 22

■ After dark, look southeast for orange Antares. (It's about five fists left of the Moon.) Antares has been called "the Betelgeuse of summer"; both are 1st-magnitude "red" supergiants. Around and upper right of Antares are the other, whiter stars of upper Scorpius, forming their distinctive pattern. The rest of the Scorpion runs down from Antares, then left. The farther north you are, the lower Scorpius will appear.

■ Three or four fists above the Moon shines Arcturus. Less than a fist to the Moon's upper left is Spica. A fist below the Moon the four-star pattern of Corvus, the springtime Crow, is slipping down and away.

TUESDAY, JUNE 23

■ At nightfall, look for Spica about 5° upper right of the Moon. Later in the evening, as the sky twists, Spica will shine more directly to the Moon's right.

WEDNESDAY, JUNE 24

■ Leo the Lion is mostly a constellation of late winter and spring. But he's not gone yet. As twilight ends look due west, upper left of bright Venus, for 1st-magnitude Regulus, his brightest and now lowest star. It's the forefoot of the Lion stick figure.

The Sickle of Leo extends upper right from Regulus. The rest of the Lion's constellation figure runs for almost three fists to the upper left from the Sickle, to his tail star Denebola, now the highest. Leo will soon be treading offstage into the sunset.

THURSDAY, JUNE 25

■ Venus and Jupiter now shine 15° apart in the western sky as twilight fades, making a diagonal line. Extend the line the same distance upper left from Venus tonight and you'll land on fainter Regulus, magnitude +1.4. How early in twilight can you first see Regulus pop into definite view?

FRIDAY, JUNE 26

■ This evening the waxing gibbous Moon shines under the three-star head of summery Scorpius, as shown below. Orange Antares, the Scorpion's 1st-magnitude heart, glimmers 5° or 6° to the Moon's left. That's about three finger-widths at arm's length.

SATURDAY, JUNE 27

■ Now the waxing gibbous Moon shines to the lower left or left of Antares, again by about 6°, as shown above.

■ This is the time of year when the two brightest stars of summer, Arcturus and Vega, shine about equally high overhead shortly after dark: Arcturus toward the southwest, Vega toward the east.

Arcturus and Vega are 37 and 25 light-years away, respectively. They represent the two commonest types of naked-eye star: a yellow-orange K giant and a white A main-sequence star. They're 150 and 50 times brighter than the Sun, respectively — which, combined with their nearness, is why they dominate the evening sky.

SUNDAY, JUNE 28

■ These evenings the main stars of the little constellation Lyra, forming a small triangle and parallelogram, dangle down from bright Vega high in the east. The two brightest stars of the pattern, after Vega, are the two forming the bottom of the parallelogram: Beta and Gamma Lyrae, Sheliak and Sulafat. They're currently lined up almost vertically when you face them. Beta is the one on top.

Beta Lyrae is an eclipsing binary star. Compare it to Gamma whenever you look up at Lyra. For much of the time Beta is only a trace dimmer than Gamma. Eventually, however, you'll catch Beta when it is quite obviously dimmer than usual.

The orbital period of this interacting binary is just 1.4 hours short of exactly 13 days. So expect its behavior to nearly repeat every two weeks minus one day throughout any given year's observing season.

Beta Lyrae's exact brightness varies continuously, as shown in this light curve below. Data courtesy AAVSO.

This Week's Planet Roundup

Mercury sinks even lower in the afterglow of sunset this week, and it also fades from magnitude 1 to 2. Catch it while you can; look for it starting about 40 minutes after sunset, 4° or 5° to the lower right of Jupiter low in the west-northwest.

Venus and Jupiter, the two brightest planets, still shine in the western sky during twilight, but they're moving ever farther apart. Venus is the higher one and brighter at magnitude –4.0. Jupiter is an eighth that bright at magnitude –1.8. On Friday the 19th you'll find them 10° apart. By Friday the 26th they'll widen to 16° apart.

Jupiter now sets in twilight. Venus sets about a half hour after twilight ends.

Mars, magnitude +1.3, remains low in the east as dawn brightens. Hunt for it about four fists to the lower left of much easier Saturn.

Saturn, magnitude +0.8, rises around 1 a.m. Catch it nicely up in the in the southeast as dawn begins to brighten. Nothing else there is as bright; it's at the border of dim Pisces and Cetus.

Don't confuse steady Saturn with flickering Fomalhaut, its near-twin in brightness, twinkling four fists to Saturn's lower right in the south-southeast.

Uranus, magnitude 5.8, is still hidden in the sunrise glow.

Neptune, magnitude 7.9, hides about 9° from Saturn before dawn.

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.

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 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, photography-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 units, relatively low priced. 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 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, The Demon-Haunted World: Science as a Candle in the Dark

"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, in the summation of his unpopular, but successful, defense of British soldiers in the Boston Massacre trial

"Truly, whoever can make you believe absurdities can make you commit atrocities."
            — Voltaire, 1765, Questions sur les miracles