Across the sky, two bright planets are well placed in the southeast for viewing. Saturn is first, shining at magnitude 0.3 in western Capricornus. It stands 14° high at sunset. Jupiter follows Saturn across the sky, located 18° farther east in Capricornus. At magnitude –2.9, the giant planet clearly outshines Saturn. Both planets are past opposition, which they reached in August, and are best viewed from 10 P.M. local time onward, when they stand high in the southern sky.
Saturn is a stunning object in any telescope, revealing its magnificent ring system encircling the 18"-wide planetary disk. The rings are tilted 19° to our line of sight, with their northern face on view. Over the next few years, the rings will become narrower, revealing more of the planet’s southern hemisphere. The outer dusky Ring A is separated from the brighter Ring B by the Cassini division. If you can easily make out the division, your seeing conditions are good. The planet shines with a yellowish hue and rarely reveals significant features unless a storm erupts, visible as an obvious white spot.
Titan is Saturn’s brightest moon, shining at magnitude 8.5. It orbits Saturn every couple of weeks and appears north of the planet Sept. 3 and 19, and south of the planet Sept. 11 and 27.
Rarely, a field star of similar magnitude enters the field of view, as on Sept. 12 and 13. On the 12th, the two are near each other southwest of Saturn; on the 13th, Titan remains southwest and the slightly brighter field star is southeast of the planet at a similar distance.
Magnitude 12 Enceladus tours around Saturn a few arcseconds from the bright edge of the rings, which make it hard to spot. A collection of brighter 10th-magnitude moons — Tethys, Dione, and Rhea — orbit a bit farther out with periods ranging from two to five days.
Iapetus is at inferior conjunction with Saturn on the last day of August. As September opens, it lies 1.5' southwest of the planet and glows near 11th magnitude. The moon brightens throughout the month, reaching a peak around magnitude 10 at western elongation Sept. 20, when it stands 9' due west of Saturn. The change occurs as its brighter trailing hemisphere becomes more visible from Earth at western elongation.
Jupiter’s retrograde loop carries it deeper into western Capricornus, passing 1.5° north of 3rd-magnitude Deneb Algedi on Sept. 12. The planet is due south at roughly 35° altitude at local midnight (depending on your local latitude). This is a few degrees better than last fall. Higher elevation means less interference from our own turbulent atmosphere, producing a brighter planet for those capturing video.
Observing Jupiter is always a thrill. The planet exhibits two thick dark equatorial belts on a broad 48"-wide disk. Brighter zones to either side of these dark belts are replete with both subtle and not-so-subtle cloud features, which the planet carries along with its rapid rotation period of less than 10 hours. Occasionally, the Great Red Spot makes an appearance. Such features move visibly within 10 minutes, making the planet a hit with all observers.