March ’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 evening sky becomes less dramatic this month, as Saturn and Neptune spend the entire month hidden in the Sun’s glare, reaching solar conjunction on March 12 and 19, respectively, while Venus and Mercury pass out of the sunset sky by month’s end – so enjoy them while you can. Mercury shows us its best evening apparition of the year during the first half of March, thanks to the steep evening ecliptic that translates much of its separation from the Sun into distance above the horizon. It begins the month at mag -1.0 with a 6 arcsecond gibbous disk that becomes a crescent by March 12. It sets at least an hour after the Sun from March 1-17, reaches inferior conjunction on March 24, and emerges into the morning sky in early April. Venus follows a similar path, beginning March as a 15% illuminated crescent nearly 49 arcseconds across, blazing at mag -4.8. It sets at least an hour after the Sun until the 17th but disappears in the solar glare soon thereafter, reaches inferior conjunction on the 22nd, and can be seen in the predawn sky before month’s end as a narrow crescent, 57 arcseconds wide and just 4% lit, 6° above the horizon a half hour before sunrise on the 31st. Uranus sets before midnight as March opens and before 11 pm as it ends, its 3.5 arcsecond powder blue disk glowing at mag 5.8 throughout the month. Jupiter remains the evening’s headliner, cruising high in the S and SW sky from sunset on. It sets shortly before 1:30 am on March 1 and around 12:45 am on the 31st, fading slightly from mag -2.3 to -2.1 and shrinking from 40 to 36 arcseconds along the way. Mars follows Jupiter at a distance, but just as high in the sky, setting after 4 am as March begins and around 3:30 am as it ends. As it did last month, the red planet forms a slowly-shifting triangle with Castor and Pollux for most of March. Its recent opposition seems long ago as it fades from mag -0.3 to +0.4 and shrinks from 11 to 8 arcseconds during the month. The asteroids don’t provide any easy opportunities this month, with none of them in the mag 9 or brighter range.
March 1: a gorgeous pair of crescents grace the sunset sky tonight as the barely two-day-old Moon, just 5% illuminated, drifts towards the horizon 6½° ahead of brilliant Venus, its 49” disk blazing at mag -4.8 despite being only 15% lit. At 6:27 pm CST (45 minutes after sunset), Venus is just over 20° up, with the Moon 5° below and slightly to the left. Mag -1.0 Mercury shows us its gibbous phase 10° below right of the Moon. Neptune completes the tableau, its faint 2” disk 2° left of Mercury and glowing feebly at mag 8.0, but you’ll need a telescope to tease it out of the gloaming.
March 4: the shadow of Ganymede crosses Jupiter from 4:41 to 7:08 pm CDT, and Europa’s shadow does the same from 5:37 to 8:13 pm, producing a double shadow transit from 5:37 to 7:08 pm. The Sun sets at 5:46, giving us an opportunity to see just how soon after sunset we can spot the shadow of a Galilean moon sliding across Jove’s variegated cloudtops. Jupiter won’t be a naked eye target at that point, but you can find it 21° east (above and left) of the 32% illuminated Moon. After you spot the Jovian moons’ shadows, use binoculars or a wide-field eyepiece to scan 4½° to the lower left of the Moon, where you’ll find Uranus as a pale blue dot shining at mag 5.8. When you run into a pair of mag 5.3 stars separated by 40 arcminutes, you’re almost halfway there. See if you can pull the planet out of the moonglow before it sets, shortly after 11:30 pm.
March 6: the Lunar X makes a twilight appearance tonight. Look along the dark side of the terminator, about midway between the lunar equator and its south pole, where a ghostly, scraggly X appears to be written in white paint. It will be in good position from about 5:00 to 8:00 pm CST. The Sun will set at 5:48 pm, so see how soon after that you can spot the X. You’ll need a telescope or mounted binoculars to make it out.
March 8: Mercury reaches greatest eastern elongation for this apparition at 18° from the Sun, its mag -0.3 disk standing 8° above the horizon at 6:35 pm CST (45 minutes after sunset). Meanwhile, ruddy Mars manages to stay 2° ahead of the gibbous Moon as they cross tonight’s sky, forming a 6° triangle with Castor and Pollux. At mag -0.1, tiny Mars might be difficult to spot in the lunar glare.
March 9: Daylight Savings Time begins at 2 am – and whether it ever ends remains to be seen.
March 11: it’s a less challenging but more satisfying Jovian event tonight, as Europa’s shadow crosses the planet from 9:13 to 11:48 pm CDT, followed by the shadow of Ganymede from 9:42 pm to 12:10 am, giving us a double shadow transit from 9:42 to 11:48 pm.
March 12 and 13: Mercury (inching a little higher each day) and Venus (slipping lower) are virtually neck-and-neck on the 12th and 13th. Look for the pair 10° above the horizon around 7:25 pm CDT (a half hour after sunset). Venus will be easy at mag -4.3 both nights. Mercury will be 6° to the left and much more challenging, at mag +0.6 on the 12th and +0.9 on the 13th. You’ll need binoculars or a telescope to pick it out.
March 13: stay up late tonight to check out the first total eclipse of the Moon since November 2022. The ingress partial phase begins when the Moon begins to enter Earth’s umbral shadow at 12:09 am CDT. Lunar totality runs from 1:26 to 2:32 am (maximum eclipse at 1:59 am), followed by the egress partial phase until 3:48 am. The Moon will pass through the NE portion of Earth’s shadow, not through its center, so its red coloring will be relatively light, and the Moon’s NE limb will be noticeably brighter than the SW limb.
March 16: if you’re lucky enough to be in a dark spot during the next two weeks, keep an eye out for the subtle beauty of the zodiacal light rising above the west horizon as a faint tall triangle after sunset.
March 19: Io marches across Jupiter from 7:07 to 9:19 pm CDT, followed by its shadow from 8:23 to 10:35 pm.
March 20: the vernal equinox arrives at 4:01 am CDT, bringing the promise of another Spring.
March 22: get up early to see the Moon perched just above the spout of the Sagittarius “teapot” – one of the most southerly positions the Moon can reach in its 18.6 year orbital cycle. Best views from 5 to 6 am CDT.
March 23: Saturn’s ring plane crossing occurs tonight – but since it’s too close to the Sun for visual observation, we won’t get to see it happen. Nonetheless, when Saturn emerges into the morning sky next month, we’ll be looking at the south face of the rings, which we haven’t seen since the last ring plane crossing in 2009.
March 26: it’s another Io transit tonight, as the hot little moon treks across the Jovian disk from 9:05 to 11:17 pm CDT, followed by its shadow from 10:19 pm to 12:31 am.
March 30 and 31: New Moon came at 5:58 am CDT on the 29th. Look due west for the paper-thin crescent around 7:45 pm CDT (a half hour after sunset), 14° above the horizon on the 30th and 28° up on the 31st.
Rick Gering / March 2025