Binoculars are a prime accessory for enhancing enjoyment of sky watching—but unfortunately, the recently discovered comet C/2025 F2 (SWAN), which we mentioned in the print version of this column, will NOT become visible to unaided eye or even binoculars, because it disintegrated as it made its closest approach to the sun.
Download free copies of the Abrams Planetarium Sky Calendar and May evening skies constellation map for May 2025 (more on these later), and note the first diagram on the calendar showing the sky 1 1/4 hours after sunset. That’ll help you star-hop from Jupiter, to Aldebaran, the Hyades and the Pleiades, where you’ll be aiming your binoculars close to the comet. Another illustration in the first row is a finder chart for the brightest asteroid Vesta, discovered in 1807. At opposition at magnitude +5.7 on May 1, and closest to Earth on May 5, Vesta is now bright enough to be seen with the unaided eye in a dark sky, and is readily seen through binoculars. Through May 5, Vesta is the brightest object inside the triangle formed by the stars Mu in Virgo (magnitude 3.9), 16 in Libra (magnitude 4.5), and 11 Librae (magnitude 4.9).
Low in the west at dusk at the start of May each year, poised to depart within next three weeks, are many winter stars: Rigel, the Pleiades, the Hyades and Aldebaran, Orion’s belt, Sirius and Betelgeuse. Binoculars enable us to follow them deeper into twilight. See the evening mid-twilight map depicting the sky when the sun is 9° below the horizon, when the brightest stars and planets have become visible. The moon and planets add year-to-year variety to the annual cycle of stars.
Binoculars give close-up views of the moon passing stars and planets. During evenings in May 2025, watch for moon-Pollux–Castor on May 2; the moon, Mars (magnitude 1.0) and the Beehive cluster on May 3; and Mars-Beehive, interesting to follow for several evenings around May 4 as the red planet shifts east by 0.5° per day, ending May at magnitude +1.3, while 9° west of Regulus. Watch for moon-Regulus on May 5; and moon-Spica on May 9.
Also in the evenings, find Jupiter at magnitude -2, brightest evening “star,” in the west at dusk, setting 3-4 minutes earlier each night, while slowly passing between the tips of the horns of Taurus, the Bull. Telescopes provide closeup views of Jupiter and its four largest moons discovered by Galileo, and of Mars. Although Mars is much more distant now compared to its close approach last January, perhaps you can view it well enough to discern its North Polar Cap as a tiny white dot, greatly diminished because the Red Planet’s northern hemisphere summer solstice occurs on May 29.
Bright stars visible in the evening not yet mentioned are golden Arcturus, in the east; blue-white Vega, rising in the northeast; and yellow Capella, in the northwest. These three stars all shine at magnitude zero, ranking after only Jupiter and Sirius in brightness in the current evening sky. By the end of May, only the top stars of the Winter Ellipse remain in view—Procyon, Pollux, Castor and Capella, forming the Spring Arch.
From the late evening on May 13 until dawn on the 14th, binoculars show the waning gibbous moon drifting past Antares.
Mornings: From the Coachella Valley at latitude 34° N, Venus (magnitude -4.7) rises before the onset of twilight and climbs higher in a dark sky. As sunrise approaches, binoculars magnify Venus enough to show it is currently a crescent, 29% lit and 36” (arcseconds) across on May 1, to 49% lit but a smaller, more challenging 24” on May 31. Saturn appears 3.9° to Venus’ lower right on May 1. Binoculars make Saturn easier to spot as it rises during twilight.
About two hours before sunrise on May 6, arrange to be in a dark place to watch the peak of the Eta Aquariid meteor shower, from Halley’s Comet, due to return in July-August 2061. Also that morning, Saturn (magnitude +1.2) rises with Venus, 5.1° to the brighter planet’s right. May 6, 2025, is a very special date for Saturn: It’s the once-in-29.4 years autumnal equinox for its northern hemisphere, when the equatorial rings are presented edge-on to the sun, and the southern face of the ring begins to receive sunlight, but at a very low angle of incidence. Saturn appeared ringless before May 6, because the shaded side was tipped toward us after Earth crossed Saturn’s ring-plane on March 23, but now that same side will gradually brighten. From May 6-31, as seen from Earth, Saturn’s dimly lit rings appear tipped by 2.2° to 3.1°, while sunlight illuminates them from a very grazing angle of 0° to 0.37°. At month’s end, Saturn appears 24° to the upper right of Venus, and faint, eighth-magnitude Neptune appears 1.7° to the left of Saturn. Through binoculars, note the attractive, compact, crude rectangle of stars numbered 27, 29, 33, and 30 in Pisces to the lower right of Saturn. The asterism’s stars range from 4.4 to 5.1 in magnitude, and its dimensions are roughly 3° by 1°. Saturn passes north of the rectangle this month.
Bright stars visible during May mornings include Arcturus in the west; Vega nearly overhead; with nearby Altair and Deneb completing the Summer Triangle; Antares in the southwest; and Fomalhaut rising into the southeast.
The Milky Way at this time of year is best seen just before morning twilight begins to brighten, when the Summer Triangle is nearly overhead. The sky is dark and moonless just before twilight on May 1-7 and again May 25-31—the first and last weeks of the month. The Milky Way band contains many beautiful binocular targets in our galactic plane, many of them star clusters and nebulae. The brightest patches of the Milky Way are the Cygnus Star Cloud, along the neck of the Swan, inside the Summer Triangle; and the Greater Sagittarius Star Cloud, just above the spout of the Teapot.
The evening sky is dark and moonless at the end of evening twilight this month from May 15-27. At that time, the brightest star of the Big Dipper, in its handle, is almost directly above the North Star, while the “W” of Cassiopeia lies near the northern horizon below the Pole Star, and the Milky Way lies near the horizon all the way around. It’s not a good time for viewing the Milky Way! When you look overhead, you’re looking out into intergalactic space, almost perpendicular to the plane of our galaxy. Near that direction from our solar system’s location within our galaxy is the star cluster Coma Berenices, the Hair of Queen Berenice, about 300 light years away.
Thin crescent moons provide wonderful views through binoculars! Try for the old moon just before sunrise on May 26, and an easier, naked-eye young moon with earthshine at dusk on May 27. Spotting opposing crescent moons on consecutive days is a very rare accomplishment. During May, I’ll have details for selected locations in the U.S., including Palm Springs, posted at abramsplanetarium.org/msta.
Three of us at Abrams Planetarium deploy our binoculars for another hobby—bird-watching!—and we encourage you to “get out and about, and keep an eye out for those endless forms most beautiful and most wonderful.”
The Abrams Planetarium Sky Calendar is available by subscription from www.abramsplanetarium.org/skycalendar. Each monthly issue consists of a calendar page illustrating events such as mentioned in this article, and an evening sky map. For $12 per year, subscribers receive quarterly mailings, each containing three monthly issues. The May 2025 issue, with a detailed evening star chart, will be available for free at that weblink by late in April.
The Astronomical Society of the Desert will host three star parties this month: on Saturday, May 3 and May 31, at the Santa Rosa and San Jacinto Mountains National Monument Visitor Center; and on Saturday, May 17, at Sawmill Trailhead, a site in the Santa Rosa Mountains at elevation 4,000 feet. For more information, including maps and directions to the two observing sites, visit astrorx.org.
Robert Victor originated the Abrams Planetarium monthly Sky Calendar in October 1968 and still helps to produce an occasional issue. He enjoys being outdoors sharing the beauty of the night sky and other wonders of nature.
Robert Miller, who provided the evening and morning twilight charts, did graduate work in planetarium science and later astronomy and computer science at Michigan State University, and remains active in research and public outreach in astronomy.
Jeffrey Hunt, who provided the graph of morning planets’ rising times through the end of 2025, and listing of morning planetary events, is a retired planetarium director now living in the Chicago area. He has taught astronomy and sky watching to people of all ages. He studied astronomy education at Abrams Planetarium at Michigan State University. Jeffrey writes an astronomy blog at jeffreylhunt.wordpress.com and can be followed on X at @jeff_hunt.
