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June 23: Try out the Turtle Nebula
Now shining at magnitude 10.6, main-belt asteroid 21 Lutetia is sliding just south of a 9th-magnitude field star in Scorpius. The best time to observe is late in the evening in the hour or two around midnight, when this region is highest in the south. Lutetia passes just under 4’ due south of the star (HIP 78769) around 10:20 P.M. EDT, then slowly inches to its southwest as time passes.
However, it will likely be difficult to catch the asteroid’s motion in a single night. Come back tomorrow to check out this region again, and you’ll definitely note Lutetia has moved, sitting southwest of a second, fainter field star on the 25th, all three dots in a line.
While you’re here, though, your eye likely can’t help but catch on Omega1 (ω1) and Omega2 (ω2) Scorpii, about 0.7° to the southeast. This widely spaced pair of 4th-magnitude stars are lovely to look at in binoculars. And about 0.6° to Lutetia’s north is 3rd-magnitude Beta Scorpii, a double whose two components are easy to split in any telescope, standing 14” apart.
Sunrise: 5:32 A.M.
Sunset: 8:33 P.M.
Moonrise: 4:06 P.M.
Moonset: 1:41 A.M.
Moon Phase: Waxing gibbous (80%)
*Times for sunrise, sunset, moonrise, and moonset are given in local time from 40° N 90° W. The Moon’s illumination is given at 10 P.M. local time from the same location.
Saturn’s two-toned moon Iapetus is now halfway between its eastern and western elongations. Heading toward the latter, which it will reach in just a few weeks, the moon sits 1.9’ due north of Saturn in the early-morning sky on June 25. Shining around 11th magnitude, Iapetus has brightened roughly a magnitude from its fainter eastern elongation and will continue to brighten as it moves westward.
Pull out your telescope about two hours before sunrise, when Saturn has reached an altitude of 20° in the eastern sky. It’s easy to find the ringed world, as it’s the brightest object in this part of the sky. Once you home in on Saturn, you’ll of course see its stunning ring system, stretching nearly 40” across as it encircles the planet, whose angular size is 17”.
Saturn’s brightest moon, Titan, should be easy to spot some 1.7’ to the planet’s west. Tenth-magnitude Tethys, Rhea, and Dione are visible as well, clustered closer to Saturn. Dione sits west of Saturn, while Rhea and Tethys are to the planet’s east. And, again, 11th-magnitude Iapetus is north of the planet, about 1.9’ from its center.
Alison Klesman is senior editor of Astronomy magazine. She holds a Ph.D. in astronomy and has studied a variety of topics, from minor planets to supermassive black holes.
