April ’24 – Rick’s Picks

All month: planet-watchers won’t have much to do on April evenings this year, since Mercury will vacate the sunset sky before the end of April’s first week, heading for inferior conjunction on the 11th and reappearing as a morning star low in the sunrise sky at month’s end, while Jupiter (mag -2.1) and Uranus (mag 5.8) set roughly three hours after the Sun as the month opens, but barely an hour after sunset when it ends. On the morning side of things, Venus slides into the solar glare early in the month, reaching superior conjunction on June 4 and barely emerging as an evening target in late July. Mars remains low in the morning sky all month, only 6° above the horizon an hour before sunrise on the 30th, its disk growing almost imperceptibly from 4.5 to 4.7 arcseconds as its brightness hovers in the +1.1 to +1.2 range. Saturn is the closest thing we’ll have to a star performer, but even the ringed planet can manage only 10° of elevation an hour before sunrise at month’s end, while it matches Mars at mag +1.1 to +1.2, its 16 arcsecond disk sitting within 36 arcsecond rings that are now tilted only 4° to our line of sight. Neptune makes its reappearance in the morning sky towards the end of the month, its 2 arcsecond disk shining at mag 7.9, joining Mars around 6° up an hour before sunrise on the 30th. Comet 12P/Pons-Brooks reaches perihelion on April 21 and may reach mag 4 by then, but it still lacks any significant visible tail, and it’s an increasingly difficult target low in the evening twilight throughout April. Use this month’s charts to find it below Jupiter until it becomes lost in the Sun’s glare after mid-month. Out among the asteroids, 4 Vesta is sinking too low in the west to be an easy target after sunset, but 2 Pallas is at mag 9.0 and fairly easy to find near Alpha () Herculis all month. This month’s charts will show you how to find it.

April 1+2: early risers can begin April Fool’s Day with a view of the Moon tracing a strikingly low path across the morning sky, a result of Springtime’s low sunrise ecliptic and the Moon being at the southern extreme of its orbit, placing it 5° below the already low plane of the ecliptic. Look for it near the spout of the Sagittarius teapot between 3:00 am CDT and sunrise on the 1st, and below left of the teapot’s handle beginning around 3:30 am on the 2nd. If you’re still up a couple hours later, look low in the east between 5:45 and 6:00 am both mornings to see mag +1.2 Mars rising with mag +1.1 Saturn trailing 6° behind. Later , look for tiny crescent Mercury 4-5° above the western horizon round 8:00 pm CDT (45 minutes after sunset).

April 5+6: Mars and Saturn are still rising in tandem around 5:30 am CDT, now separated by only 3-3½°, but on the 5th they’re joined by a thin, 16% illuminated crescent Moon 10½° to the right of Mars, and on the 6th by an even narrower 8% illuminated crescent just 2° below the pair of planets, putting all three targets within the same 5° binocular field.

April 7: the crescent Moon will occult Venus in daylight, but since it will happen just 7½° from the midday Sun, it’s an observation that should be attempted only by those of you who have enough experience in daytime solar avoidance techniques that you don’t need me to tell you when it is or how to find it.

April 8: the new Moon brings us a rare treat this month, as the second North American total solar eclipse of the 21st Century crosses from Mexico to Newfoundland. Wishing you clear skies wherever you go to observe it.

April 10+11 (morning): mag +1.2 Mars and mag +1.1 Saturn are only a half-degree apart as they rise around 5:15 am CDT. By 5:30 (45 minutes before sunrise) they’re nudging up to 5° elevation. Look for the subtle color contrast between the dirty yellow of Saturn’s orb and the pale red of Mars: it should be easily seen in binoculars, but can you see it naked eye?

April 10 (evening): mag 4.9 star Zeta () Arietis slips behind the dark limb of a paper-thin 7% illuminated crescent Moon in a twilight sky at 7:54 pm CDT (27 minutes after sunset), and pops back out on the sunlit edge an hour later, over several minutes beginning at 8:48 pm. While it’s hidden, feast your eyes on a marvelous scene as the sparkling Pleiades (M45) watch from their perch 7° above and slightly left of that delicate crescent Moon, with mag -2.0 Jupiter 4° below and slightly left of it, mag 5.9 Uranus visible in binoculars less than 2° directly above Jupiter, and comet 12P/Pons-Brooks cruising along 4° below right of Jupiter, directly below the crescent. Wow! The tableau comes to an end as the comet sinks below the horizon at 9:30 pm, followed by Jupiter at 9:47 and the Moon at 10:20 pm.

April 11 (evening): the slightly-wider 14% illuminated crescent Moon strolls down the western sky tonight with the Pleiades 6° below and to its right and the Hyades about the same distance to its left. Meanwhile, Jupiter, Uranus, and 12P/Pons-Brooks repeat their April 10 performance, stretched out over 5° of vertical space, 10° to 15° directly below the Pleiades, giving you a second chance to watch it.

April 15: look for the Lunar X along the terminator between 9:45 and 11:45 pm CDT tonight, roughly halfway between the Moon’s equator and its south pole.

April 19: at 11:23 pm CDT, the Moon seems to step backwards and pull mag 4.1 star Sigma () Leonis behind its narrow dark limb. Be sure to start watching several minutes before that so you don’t miss the moment of disappearance!

April 21: the Lyrids meteor shower peaks after midnight tonight at 2 am CDT, but a 97% lit Moon will disrupt the party like the arrival of the campus police, reducing the shower’s usual dark-site maximum of 20 meteors per hour to low single digits at best. The Lyrids are active from April 14-30, so keep an eye out for them throughout the second half of the month, but they have a fairly narrow peak (only 1.3 days at or above 50% of maximum) so don’t expect a prolific meteoric parade. The Lyrids are debris from comet C/1861 G1 (Thatcher).

April 22: the full Moon crosses the sky tonight joined at the hip with Spica (Alpha [] Virginis). The pair come as close to each other as a half-degree of separation around 10 pm CDT.

April 27 (night of the 26th): night owls and early risers can check out the color contrast as the 90% illuminated Moon chases 5° behind ruddy Antares (Alpha [] Scorpii) while the pair cross the sky from 11 pm til sunup.

April 29: it’s worth getting up early today to see mag +1.1 Mars rise just a tenth of a degree from mag 7.9 Neptune. You’ll need at least binoculars, and probably a telescope, to see this pairing – but the color contrast between ruddy red Mars and deep blue Neptune should be gorgeous. They rise in tandem at 4:20 am CDT and reach 5° elevation just after 4:48 am (an hour before sunrise), reaching 7° by 5:00 am.

Rick Gering / April 2024