May ’25 — Rick’s Picks

Transient Events That Can Give Us a Good Enough Reason to Get Outside and Do a Little Observing

 All month: the planets continue their exodus from the evening sky this month. Uranus is now lost in the solar glare – it will reach conjunction on May 17 and return as a morning target in June. Jupiter joins it among the invisibles by mid-month, while Saturn and Neptune complete their abandonment of the evening and become visible in the morning twilight. As May begins, Venus is the first planet to greet the predawn sky, rising at 4:04 am CDT as a brilliant thick crescent 36” across, 29% lit, blazing at mag -4.7, and 10° above the horizon an hour later. By month’s end it rises 45 minutes earlier, a 24” disk 49% lit at mag -4.5. It reaches greatest western elongation on May 31 at 46° from the Sun. Saturn follows just 10 minutes behind Venus on May 1, but as May ends it rises at 2:22 am, nearly an hour before Venus, reaching 15° elevation by the start of civil twilight at 4:44 am. During the course of the month, the ringed planet grows imperceptibly from 16” to 17” and fades from mag +1.2 to +1.1 while the rings barely rise above flat, tilted only 2° to our line of sight. Neptune follows within a couple minutes of Saturn all month: its 2” mag 7.9 disk becomes visible in binoculars late in the month, 1°-2° to the left and slightly above Saturn. Mercury is the last planet up as the month opens, rising at 4:59 am on May 1 (just 47 minutes before the Sun), but quickly becomes lost in the morning glare on its way to superior conjunction on May 29. Turning to the evening sky, Jupiter sets at 11:05 pm on May 1 and 9:37 pm on May 31, but even as May begins it’s only 23° above the horizon an hour after sunset, and by midmonth it’s lost behind the treeline from most locations by 9 pm. It shines at mag -2.0 all month long. That leaves Mars to round out the evening, setting shortly after 2 am on May 1 and before 1 am on May 31, shrinking from an already-small 6½” to a positively tiny 5½” and fading from mag +0.9 to +1.3 along the way – so don’t expect to spot any surface features for a while, although from May 1-8 the Red Planet is close enough to the Beehive Cluster (M44) to fit in the same 5° binocular field. Among the asteroids, 4 Vesta reaches opposition on May 2 at mag 5.6 and makes its closest approach to Earth on May 7, providing binocular views from the suburbs around 10 pm all month and naked eye views from dark sites (especially from May 14-29 when the Moon is out of the picture). This month’s charts will help you find it.

May 3 (morning): begin the day with a really difficult pre-dawn triple conjunction: start with the bright beacon of Venus at mag -4.7, then look 4° to the right and a half degree down to find Saturn, just 1/200 as bright at mag +1.2. Then for the real challenge, try to spot mag 7.9 Neptune in binoculars, 1.5° below Venus and 1° to its right (and only 1/100,000 as bright). Don’t confuse Neptune with a mag 6.3 star a half degree closer to Venus. At 4:43 am CDT (an hour before sunrise), Venus will be just over 7° above the horizon, with Saturn at 6.5° and Neptune just under 6° elevation.

May 3 (evening): get your binoculars again to catch the not-quite first quarter Moon, mag +1.0 Mars, and the stars of the Beehive Cluster (M44) gathered within a 5° field. You’ll need the binos to see the Red Planet’s color in the bright moonlight, and will need to get the Moon out of the field altogether to get the

best views of the Beehive’s stars. Mars and the cluster remain within a degree of each other all night, while the Moon passes within 1.5° of Mars around 8:30 pm CDT. The pair gradually separate as the evening goes on, and end up about 4° apart when all three targets set around 2 am. If you watch carefully in binoculars or a telescope, you might also see mag 4.7 star Gamma () Cancri disappear behind the Moon’s dark limb at 9:05 pm: as with all occultations, be sure to start watching a few minutes before then so you don’t miss it!

May 4: get your binoculars and check along the terminator (the line dividing day and night on the Moon) between the lunar equator and the south pole from 8 pm to midnight CDT tonight to see the ghostly white scrawl of the Lunar X emerge from the crater rims – then look farther north along the terminator for its cousin, the Lunar V. While you’re at it, swing a little farther to the west where Mars sits just above the top of the triangular Beehive Cluster like the rosy-cheeked head on a floppy rag doll.

May 5: the Eta Aquarids meteor shower peaks overnight. Composed of debris from the outbound path of comet 1P/Halley (whose inbound debris stream gives us the Orionid meteors in October), the Eta Aquarids are active from April 19 to May 28 and exhibit a remarkably broad peak, remaining at 50% maximum or more for 5 days. They’re primarily a southern hemisphere show: in our part of the world, even under moonless skies, you’ll see only around 10 meteors per hour at a dark site, or 3-4/hour from the suburbs. This year, the shower will be badly affected by a bright gibbous Moon that won’t set until 3 am CDT, a half hour after the radiant rises and two hours before the beginning of civil twilight – so night owls and very early risers can at least get in a couple hours under relatively dark skies. The Eta Aquarids are fast movers (around 66 km/sec) and exhibit a fair number of persistent trains, so even a short session might include some impressive views.

May 6: it’s the equinox on Saturn, when its rings align with the Sun – so until May 5 we see them backlit, but starting tomorrow, sunlight will illuminate the south face of the rings for the first time since 2009.

May 9: the 94% illuminated Moon crosses tonight’s sky within 2° of mag 1 Spica (Alpha [] Virginis). The gap narrows as the night goes on, nearing 1° when the pair set shortly after 4 am CDT.

May 13: the almost-full Moon (98% lit) rises hand-in-hand with reddish Antares (Alpha [] Scorpii) shortly after 9:30 pm CDT. The pair remain close as they amble across the sky, setting in bright morning twilight. You’ll need binoculars (and might have to keep part of the Moon out of the field) to see the color contrast.

May 23: early risers are greeted by an elegant view as bright Venus, a delicate 20% illuminated crescent Moon, and much fainter Saturn rise above the east horizon in a 15° arc. You’ll need binoculars or perhaps a telescope to add dim Neptune to the tableau, 2° to the left of Saturn (and only 1/500 as bright). The group will be visible from 3:30 am CDT, when Venus rises, until growing twilight wipes out the scene around 5 am.

May 26+27: with New Moon arriving at 10:02 pm CDT on the 26th, we have an unusual opportunity to see a waning crescent and a waxing one on consecutive days. The morning view is the harder one: at 4:50 am CDT on the 26th (a half hour before sunrise), the Moon will be 2½° above the NE horizon, 29° left of due east, a vanishingly thin crescent just 0.8% illuminated, and 17 hours before new. At 8:46 pm on the 27th (a half hour after sunset), it will be 7° above the NW horizon, directly above the spot where the Sun went down, an extremely thin crescent 1.3% illuminated, and 22¾ hours old. Give yourself a gold star if you spot them both!

May 30: today is the summer solstice on Mars – but you’ll still have to wait til next month for the one that matters to us.

Rick Gering / May 2025