Saturn reaches opposition at 2 A.M. EDT Aug. 2. Rising in the southeast as the Sun sets, you’ll find the ringed planet 15° high by 10 P.M. local time. It reaches 30° altitude by Aug. 31 at the same time. Saturn is easy to spot among the faint stars of Capricornus the Sea Goat, outshining everything in this region. The planet starts August at magnitude 0 but quickly dims to 0.2 for the rest of the month.
Like all outer planets, Saturn is best viewed near the meridian; at opposition, this is around local midnight (1 A.M. for locations using daylight time). Any backyard telescope will reveal its 19"-wide disk, encircled by the magnificent ring system spanning 42" by 13". Details of Saturn’s subtle atmospheric belts are best seen by allowing your eyes to catch fleeting periods of good seeing. Saturn’s polar diameter spans 17" and the rings’ diminishing angle to our line of sight (now 18°) reveals the south polar region.
Saturn’s brightest moon, Titan, orbits every few weeks. You’ll find it north of the planet Aug. 3 and 19, and south of the planet Aug. 11 and 26/27.
Tenth-magnitude Tethys, Dione, and Rhea hover closer to the rings, changing relative positions hourly. Fainter magnitude 12 Enceladus orbits a few arcseconds from the rings’ bright edge. On Aug. 2, this moon appears to gain a twin when a field star of similar brightness lies close to it on the east side of the rings. Just a few minutes of observation between sunset and local midnight will show their relative positions changing. The moon and star appear closest (3" apart) around midnight EDT on the 2nd. If you miss it, try again Aug. 8, when another field star passes 12" south of the moon.
Iapetus reaches eastern elongation nearly 9' due east of Saturn on Aug. 12, shining close to magnitude 12. It then moves back toward Saturn, brightening by 1 magnitude and reaching inferior conjunction 50" from Saturn on Aug. 31.
Jupiter rises an hour after Saturn and reaches opposition Aug. 19. Located in southern Aquarius, Jupiter glows a brilliant magnitude –2.8 Aug. 1 and brightens to –2.9 by midmonth. Its retrograde track carries it into Capricornus on Aug. 18. You’ll find Jupiter 5° north of the Full Moon on Aug. 21.
Jupiter is a wonderful object through a telescope. Its disk spans its widest for the year at 49" and the planet lies 4 astronomical units (AU) from Earth (1 AU is the average Earth-Sun distance). Any telescope will reveal fine details in its atmosphere, which is best seen when the planet is near your local meridian in the hour after midnight. Jupiter stands 36° high at 1 A.M. local time; it is somewhat higher for observers in southern states and lower for those in northern ones.
It’s the best time of the year to see the two dark belts straddling the equator, as well as the associated plumes and festoons of more gently shaded features. These sights move quickly with Jupiter’s rotation period, which ranges from 9 hours 50 minutes to 9 hours 55 minutes.