Transient Events That Can Give Us a Good Enough Reason
to Get Outside and Do a Little Observing
All month: it’s a frustrating month for early-rising planet fans, as Mercury, Mars, Saturn, and Neptune all achieve significant elongation from the Sun, but Spring’s flat morning ecliptic twists most of that distance into the horizontal, keeping them all much closer to the horizon than their elongations would imply, and making them challenging targets (at best) all month long. Mercury, for example, is 28° from the Sun on April 3, which is as far as it can ever be, but is still less than 5° above the horizon a half hour before sunrise. The sunset sky is a little more interesting for planetary observers, with Venus blazing at mag -3.9 all month and setting quite late – 8:55 pm as April begins and a stunning 10:07 pm as it ends. Its nearly-full disk is 11 arcseconds wide. Jupiter continues to dazzle us, setting shortly before 3 am on April 1 and after 1 am on April 30. It fades slightly from mag -2.2 to -2.0 as its disk diameter shrinks from 39 to 36 arcseconds over the course of the month. Uranus hangs on for the first half of April, setting shortly after 11 pm as the month opens but before 9:30 pm as it closes, far too faint by then to penetrate the evening twilight. Its disk is 3½ arcseconds wide and glows at mag 5.8. We get no help from the asteroids, either, since none of them remain brighter than mag 10 this month.
April 1: if you’re admiring the bright beauty of Venus when it’s about 10° above the west horizon shortly after 8:00 CDT tonight, take a few minutes to point your binoculars 25° higher and slightly to the left, where you’ll find The Pleiades (M45) – a pretty sight in twilight – then pan 4½° to the lower left and look for a line of three equally-spaced mag 6 lights: the one at the left end of the line should look a little different from the others, since that’s blue-green Uranus and the others are stars 13 and 14 Tauri. Then take a peek at Jupiter, where the Galilean moons helpfully line up on the left side of the planet in their proper order, with Io closest, followed by Europa, Ganymede, and Callisto. They stay that way until shortly after midnight, when Europa and Ganymede break ranks; if you’re still observing at 1:20 am, watch orbital dynamics in action as Europa passes just 7 arcseconds above its outer neighbor.
April 2: the almost-full Moon rises around 8:20 pm CDT just 2° behind mag 1.0 Spica (Alpha [] Virginis), but slowly falls behind the star as they cross the sky together tonight. Later, watch the shadow of Ganymede trek across the face of Jupiter from 8:58 pm to 12:22 am. While that’s happening, Europa has another close encounter with one of its sister moons, passing 7 arcseconds above Callisto at 10:30 pm.
April 3: it’s another eventful night in Jupiter space, as the most distant Galilean moon, Callisto, treats us to a rare shadow transit from 8:14 pm until 12:32 am CDT.
April 9: Ganymede crosses Jupiter from 7:49 to 11:06 pm CDT. Its shadow follows from 12:57 to 4:22 am.
April 13: tonight Europa hikes across the disk of Jove from 8:11 to 11:00 pm CDT, followed by its shadow from 10:42 pm to 1:32 am. As Europa passes the planet moving from left to right, Io approaches it moving right to left, and at the stroke of midnight the two moons pass within 5 arcseconds of one another. Stay up a little later to watch Io slip behind the edge of the planet over several minutes beginning at 1:10 am.
April 18: new Moon arrived yesterday at 6:52 am CDT, so at 8:06 pm tonight (a half hour after sunset), it will be 37 hours old, 3% illuminated, 15° above the horizon, and almost exactly above the spot where the Sun went down. Start at the bright beacon of Venus, blazing at mag -3.9, then scan 6° to the right and 2½° down. Don’t neglect The Pleiades (M45) 7½° above Venus, and Uranus 4° below left of The Pleiades. If you miss the show tonight, try again tomorrow: the Moon will be 9% lit, 27° above the horizon, and 10° directly above bright Venus, with The Pleiades roughly midway between them and slightly to the right.
April 20: for a very challenging sunrise view, find a spot with an unobstructed east horizon, and try to spot Mercury, glowing at mag -0.2 just 1½° above the horizon and almost exactly east. If you can do that, try for mag +0.9 Saturn a half-degree above left of Mercury, then mag +1.2 Mars 1.2° above left of Saturn.
April 21 and 22: the Lyrids meteor shower peaks at 2:40 pm CDT on April 22, making both of these nights good viewing opportunities. As with all meteor showers, the best views come between midnight and sunrise, when Earth takes its most aggressive bite into the debris stream. The crescent Moon (4-5 days old) is on the other side of the sky from the radiant; it will set around 1:15 am the first night and 2:00 am the second. The Lyrids are bright meteors, moderately fast-moving, with occasional fireballs and some flashes of color. They produce 18 meteors/hour ZHR, so with the Moon out of the way you can expect to see around 10 per hour from a dark site, or 3-5 per hour from the suburbs.
April 21-26: Venus is within 5° of The Pleiades (M45) all six nights. They come closest on April 23.
April 22: after a nice sunset gathering of Venus, Uranus, and The Pleiades (M45), described in detail in the April 23 entry below, look higher in the sky, where the fat crescent Moon (38% illuminated) dances just 3° above mag -2.1 Jupiter as the Gemini twins, Castor and Pollux, look on like chaperones from 5° higher still. You can watch the backwards-7 shaped group from evening twilight until Jupiter sets shortly after 1 am CDT. Along the way, watch for Io to slip behind Jupiter at 9:39 pm and re-emerge from its shadow at 1:11 am, just 3° above the WNW horizon and midway between the planet and Europa.
April 23: look west around 8:40 pm CDT (an hour after sunset) for easily-seen Venus, mag -3.9, shining 12° above the horizon. With binoculars or a wide-field telescope, scan 3½° up and right to find The Pleiades (M45) – then see if you can spot mag 5.8 Uranus, just 45 arcminutes below left of Venus: the 9.7 magnitude brightness difference means that Venus will appear 7500 times as bright as Uranus, making it extremely difficult to see them both at the same time. You can also try on April 22, when Uranus will be 1½° above left of Venus (with two mag 6 stars, 13 and 14 Tauri, less than a degree below left of the bright planet); or on April 24, when Uranus will be just under 1½° directly below Venus.
April 25: put the gibbous Moon in your telescope’s eyepiece by 7:10 pm CDT – shortly before sunset – to watch it step backwards a couple minutes later and gobble up mag 1.4 Regulus (Alpha [] Leonis). The star will slowly emerge from behind the top of the Moon over several minutes starting about 8:08 pm, but that will be considerably more difficult to see against the Moon’s bright limb.
April 29: the almost-full Moon crosses the sky escorted by mag 1.0 Spica (Alpha [] Virginis) 2½° away.
Rick Gering / April 2026