May ’24 – Rick’s Picks

All month: planet watchers are in for a boring month, as their quarry largely disappear from both the morning and evening sky. The evening’s last holdouts, Jupiter and Uranus, both set less than an hour after the Sun as May opens, and before the Sun by mid-month, reaching conjunction on May 13 (Uranus) and May 18 (Jupiter) and remaining lost in the Sun’s brilliance until beginning to re-emerge as morning targets in late June or July. Venus spends the entire month hidden in the glare, on its way to a June conjunction. Mercury is a morning star throughout May, reaching greatest western elongation on May 9 a respectable 26° from the Sun, but the relatively flat dawn ecliptic at this time of year keeps it low in the morning sky all month, reaching greatest elevation on May 12 at only 4° at 5:02 am (a half hour before sunrise). Mars puts on a similarly half-hearted morning show, barely reaching 5 arcseconds in size by May’s end and displaying a feeble mag +1.1 glow throughout the month as it, too, follows a relatively low path across the sky. Saturn is no brighter, spending the month at mag +1.2, its 16 arcsecond disk encased within now quite flat 40 arcsecond rings tilted only 3° to our line of sight as next year’s ring plane crossing nears. Neptune is out there in the early dawn as well, behind Saturn and ahead of Mars, its 2 arcsecond blue disk glowing at mag 7.9 and visible only with binoculars or a telescope. Among the asteroids, 2 Pallas will reach opposition at mag 9.0 on May 17, giving nighttime solar system observers something to do with their time. This month’s charts will show you where to find it.

May 3: start watching no later than tonight for Eta Aquarid meteors, partly because of the shower’s broad peak (see details in the May 5 entry below), and partly because this year, we’re going to pass through a particularly thick band of debris left behind by the shower’s parent comet, 1P/Halley, during its passage through the inner solar system in 985 BCE – like stirring up dust from a floor that hasn’t been swept for over 3000 years. The shower is active from April 19 to May 28 and takes us through the debris left behind during Halley’s outbound passages. Its inbound debris stream gives us the Orionids meteors in October.

May 4: early risers can start watching around 4:30 am CDT (75 minutes before sunrise) for a nice display of Solar System targets, led by mag +1.1 Saturn at the upper right end of the line, followed by a 19% illuminated crescent Moon, with Mars echoing Saturn’s brightness another step down and left from the Moon; a telescope will reveal mag 7.9 Neptune glowing faintly blue midway between those two.

May 5: the Eta Aquarids meteor shower reaches maximum at 4:00 pm CDT today, but because this shower has a broad peak, remaining at or above 50% of maximum for five days, it’s worth watching for them over a few days before and after maximum. On the other side of the coin, however, the Eta Aquarids are mostly a southern hemisphere show, with realistic rates in our part of the world only reaching around 10 meteors per hour in a dark rural sky, and only 3-5 per hour in the suburbs. What they lack in numbers, however, they make up in pizzazz: most of them are fast movers, hitting our atmosphere at ~66 km/sec (150,000 mph), with lots of persistent trains chasing them along as ionized molecules are left in their wake. As with almost all meteor showers, the prime time for catching them is from midnight to morning twilight. The roughly 20% illuminated Moon won’t be a factor until after 4 am the nights of May 3 and 4 and won’t rise until morning twilight begins on May 5 and after.

May 6: it’s another day for the morning people. Grab your binoculars at 5:10 am CDT (30 minutes before sunrise), then look 8° left of due east and 4½° above the horizon for a paper-thin 4% illuminated crescent Moon. Once you’ve spotted it, scan 4° right and 1° down to grab mag +0.6 Mercury.

May 8 and 9: new Moon arrives at 10:22 pm CDT on May 7, so at 8:43 pm CDT on May 8 (45 minutes after sunset) it will be a paper-thin arc 22½ hours old, just 1% illuminated, 3½° above the horizon, and 4½° to the right of the spot where the Sun went down. If your binocular scan shows glimmerings of a familiar-looking starry dipper, you’re in the right area, since The Pleiades will be just 1° to the right of the delicate crescent. The job will be easier at the same time on May 9, when the Moon will be nearly 2 days old, 5% illuminated, 15° above the horizon, and 2° to the left of the spot where the Sun went down.

May 17: Asteroid 2 Pallas reaches opposition tonight at mag 9.0, conveniently located near bright star Beta () Herculis. After midnight, the wonderfully-named mag 3.6 star Zavijava (Beta [] Virginis) quietly slides behind the dark edge of the 75% illuminated Moon. Start watching before 12:20 am CDT; the disappearance will occur over the following few minutes.

May 23: we’re in the midst of a Moon-Antares occultation series that began last year and continues until August 2028. Today’s episode will be a real challenge for our area. Antares will disappear behind the full (99% illuminated) Moon before it rises here and will emerge shortly after moonrise – but you’ll have to be fast, and find a spot with a view that goes literally down to the southeast horizon, where the Moon will begin to break into our sky at 8:56 pm CDT. Antares will emerge from behind the upper left edge of the lunar disk (clock position ~11:00) twelve minutes later, when the top of the Moon is just over 1° above the horizon. But what you’re watching for isn’t the big bright red giant Antares, but rather the tiny mag 5.5 secondary star that sits just 2.7” from the primary and is usually invisible in the brighter star’s brilliance. You’ll need a telescope to pick it out, and only a few seconds to spot it before the primary emerges and engulfs the smaller star in its glare. Even before the primary pops out, it will be a challenge to spot Antares B in the bright moonglow, but this is definitely a notch-in-the-belt object, and one that’s worth some effort to bag.

May 31: night owls and early risers can end the month with a nice view of Saturn less than 1° above left of a fat (42% illuminated) crescent Moon. The pair rise together shortly before 2:00 am CDT and climb into the morning sky until the brightening dawn engulfs the scene around 5 am.

Rick Gering / May 2024