Special to CosmicTribune.com, May 26, 2025

Excerpts from weekly Sky&Telescope report.

MONDAY, MAY 26

■ Catch the brightest asteroid, 4 Vesta, before it fades further. It’s nicely placed high in the south-southeast after the sky is fully dark (at least two hours after sunset now) in a moonless dark sky. It’s almost a month past opposition but still about magnitude 6.2. It’s located 24° below Arcturus, near the Virgo-Libra border and about 12° above both Beta and Alpha Librae. You’ll need the finder chart with Bob King’s article Asteroid Vesta Now an Easy Catch in Binoculars. The dates on the chart there are in Universal Time; subtract one day from them to get evening dates for the Americas.

■ New Moon (exact at 11:02 p.m. EDT; 8:02 p.m. PDT).

TUESDAY, MAY 27

■ Using binoculars 30 minutes or less after sunset, can you pick up Jupiter and the super-thin crescent Moon very low in the west-northwest? See below. Which of the two is the least detectable? Moon is only about 24 hours old at dusk in North America. Compare the time you spot it with the time of new Moon (see just above) to get the crescent’s exact age. Does this set a young-Moon record for you?

WEDNESDAY, MAY 28

■ The Moon in twilight hangs less than a fist above Jupiter, the “False Evening Star.” Jupiter is bright but hardly a match for Venus. See below.

The crescent Moon returns to the evening sky, passing Jupiter and Gemini on their way out for the season. Bye-bye.

THURSDAY, MAY 29

■ Now the Moon hangs under Pollux and Castor, as shown above.

■ Constellations seem to twist around fast when they pass your zenith — if you’re comparing them to your direction “down.” Just a week and a half ago, the Big Dipper floated horizontally in late twilight an hour after sunset (as seen from 40° N latitude). Now the Dipper angles diagonally in late twilight. In just another week and a half it will hang straight down by its handle at that time.

FRIDAY, MAY 30

■ The Big Dipper floats high in the northwest these evenings. The middle star of its bent handle is Mizar, with tiny little Alcor right next to it. On which side of Mizar should you look for Alcor? As always, on the side toward Vega. Which is now the brightest star in the east.

■ Titan casts its shadow on Saturn tonight! Only every 15 years does Titan, Saturn’s largest moon, cross Saturn’s face from Earth’s viewpoint and, more visibly, cast its tiny black shadow onto Saturn. The latest series of these events has begun. They will happen every 16 days from now to October.

Tonight Titan’s shadow crosses Saturn’s face from 9:05 UT to 14:53 UT May 31st; that’s from 5:05 a.m. to 10:53 a.m. Eastern Daylight Time May 31st; 2:05 to 7:53 a.m. PDT May 31st. Since Saturn is only up in view for a short while before and during early dawn, these times mean that only western North America is favored. And, it’s fairly likely that blurry seeing when Saturn is so low will make the shadow undetectable even in a largish telescope.

SATURDAY, MAY 31

■ The crescent Moon is approaching Mars this evening, as shown below. At nightfall in North America they’re about 4° apart.

But that’s just their apparent separation: the way they appear on the surface of the celestial sphere. In actual 3-D space the Moon is 1.3 light-seconds distant from us, but Mars is currently 650 times farther in the background at a distance of 14 light-minutes.

The waxing Moon passes Mars and Regulus, which are equal in brightness this week but, as ever, different in color. (The Moon here is drawn three times its actual apparent size. The blue 10° scale is about the width of your fist at arm’s length.)

SUNDAY, JUNE 1

■ Now the Moon leaves Mars behind to get chummier with Regulus, shining only about 1° from it (depending on your location). But at a distance of 79 light-years, Regulus is 1.9 billion times farther from us than the Moon is. A scale model: If the Moon was just a foot from your eye like on a screen, Regulus would be 360,000 miles in the background — a nuclear fireball at about the Moon’s actual distance from us!

  May 26-June 1; Jupiter sets for the season, The Sky