June ’24 Rick’s Picks

 All month: morning people continue their selfish monopolization of solar system observing this month, with Mercury (which will reach superior conjunction on June 14) being the only major planet visible in the sunset sky at all – and that’s only at the very end of the month, when the innermost planet will set at least an hour after the Sun beginning on June 27. Venus reaches superior conjunction on June 4 and remains lost in the solar glare all month long. The rest of the major planets are exclusively morning performers. Mars rises two hours before sunrise as June opens and three hours before sunrise as it ends, hovering around mag +1.0 and swelling slightly from 5 to 5½ arcseconds as the month progresses. Jupiter begins the month too close to the Sun to be safely observed, but becomes visible before sunrise during June’s second week. By month’s end it rises a full two hours before the Sun, showing us a 33 arcsecond disk and a mag -2.0 glow all month. Uranus barely precedes Jupiter into the sky as the month begins, but rises nearly 45 minutes ahead of the largest planet as June ends, its 3½ arcsecond disk glowing at mag 5.8. Saturn rises shortly before 2 am CDT on June 1 and just before midnight on June 30, preparing to move back into the evening sky, its 17 arcsecond disk encircled by nearly-flat rings that extend to 40 arcseconds and tilt less than 2° to our line of sight, glowing around mag +1.1 throughout the month. Neptune follows 20 minutes behind the ringed planet throughout June, glowing at mag 7.9 with a 2¼ arcsecond disk. Among the asteroids, dwarf planet 1 Ceres gives evening observers something nearby to hunt down, as it cruises towards the handle of Sagittarius, brightening from mag 7.9 to 7.3 on its way towards opposition in July. This month’s charts will show you how to find it.

Something special to watch for: a new jewel is expected to appear in the Northern Crown (Corona Borealis) between now and October, as the recurrent nova T Coronae Borealis – sometimes called The Blaze Star – is showing signs of an impending outburst. Novas occur in close binary systems when a white dwarf’s gravity captures a stream of gas from its larger companion. When enough gas has collected on the smaller star, it explodes in a fury of nuclear fusion. The resulting increase in brightness, called an outburst, is sudden and pronounced, often involving a jump of 5 to 19 magnitudes. Some stars collect enough stolen hydrogen to “go nova” after only few years; others collect hydrogen for centuries before they flare up. This particular nova normally remains largely unnoticed just off the lower left corner of the constellation’s familiar “U” shape, shining at a faint mag 10, but in 1866 and 1946 it suddenly rose to mag 2-3, making it about as bright as the constellation’s brightest star, mag 2.2 Alpha CrB. The nova then faded back to mag 10 over a period of several days, rising sharply to mag 8 three months later and remaining at that brightness for another three months before fading back to its original mag 10 level. Because it is the sky’s brightest recurrent nova by a substantial margin – the next brightest, RS Ophiuchi, tops out at mag 4.5 to 5 – observing a T CrB outburst is literally a once-in-a-lifetime opportunity. So keep an eye on the area a third of the way from Arcturus to Vega: normally the only bright star you’ll see there is Alpha CrB, but when instead you see two equally bright stars almost next to each other, you’ll know The Blaze Star is in outburst. This month’s charts will show you where to watch.

June 4: for a challenge in morning twilight, see if you can spot mag -2.0 Jupiter and mag -1.1 Mercury just 7 arcminutes apart and only 1° above the ENE horizon at 4:46 am CDT (a half hour before sunrise). Just be sure to step away from the eyepiece before the Sun crests the horizon!

June 7: new moon arrived yesterday at 7:38 am CDT, making it a little too challenging to try for it last night – but at 9:10 pm tonight (45 minutes after sunset), the crescent will be 37 hours old, 3% illuminated, 9° above the horizon, and just 3° left of the spot where the Sun went down. Go for it!

June 8: beginning around 8:45 pm CDT, as evening twilight descends, look about 20° up in the western sky where a delicate crescent Moon forms a well-balanced triangle with Castor and Pollux.

June 18: if you have a telescope set up in evening twilight tonight, turn it on the 91% illuminated Moon and watch a mag 5.5 star slip behind its narrow dark SE limb at 9:04 pm CDT.

June 20: the solstice arrives at 3:51 pm CDT when the Sun reaches the northern limit of its range at the Tropic of Cancer, bringing us another summer and, hopefully, some good observing weather for the next few months.

June 22 (night of June 21): stay up late tonight to see if you can catch the rare spectacle of Saturn occulting its mag 8.5 moon Titan. Find the moon nearing the planet’s NW limb (top left in refractors, bottom left in reflectors) no later than 2:45 am CDT; it will disappear behind the planet over a period of several minutes shortly after that. While you’re there, look for mag 10.4 moon Tethys skating along the NW tip of the planet’s rings.

June 22: start watching well before 11:31 pm CDT tonight to find mag 7.5 dwarf planet 1 Ceres and watch it slip behind the bright SE limb of the nearly-full Moon. It will be difficult to spot the faint asteroid in the bright moonglow. It might be an easier catch as it re-emerges from the dark west side of the Moon at 12:45 am.

June 24: if you’re up late and have lots of aperture, see if you can spot the shadow of mag 10.4 Tethys crossing Saturn just south of the rings tonight, as the little moon transits its planet from midnight until 2:30 am CDT.

June 26: the Moon and Saturn rise together tonight shortly after midnight, cross the sky only a few degrees apart from one another, and finish off their journey with a daylight occultation (see next entry).

June 27: the Moon occults Saturn in daylight, but you’ll need a view all the way to the west horizon in order to spot it. Find the Moon 10-15° left of due west by 11 am CDT and wait for faint mag +1.1 Saturn to slip behind its bright upper limb (about 1:00 position in binoculars – 11:00 in refractors – 7:00 in reflectors) at 11:12 am, when the Moon is just 3° above the horizon.

June 29: mag 7.4 dwarf planet 1 Ceres nearly touches a mag 8.5 star as the two pass each other tonight. Close approach is less than 5 arcseconds at 11:05 pm CDT.

June 30: the day begins with a display of antemeridian bravado from 3:30 am CDT until pre-dawn twilight, as the morning sky shows off six solar system targets in a line spanning 80°. Saturn leads the way, followed by Neptune, the Moon, Mars, Uranus, and Jupiter, with The Pleiades star cluster (M45) standing guard above the largest planet. Then at 9:00 pm (a half hour after sunset), look for tiny but defiant mag -0.6 Mercury taking a solitary stand for evening observers, 6½° above the horizon and 8° left of the spot where the Sun went down. Scan to the right and slightly up to find mag 1.2 Pollux and 1.6 Castor pointing back towards the planet.

Rick Gering / June 2024