The solar system’s most distant planet shares the sky with the nearly Full Moon this evening, with Saturn standing nearby.
Late in the month, the Moon forms a triangle with Saturn and Neptune — note the latter requires binoculars or a telescope to spot. Credit: Astronomy: Roen Kelly
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October 22: Iapetus at superior conjunction
The nearly Full Moon passes 5° north of Neptune at 11 P.M. EDT, creating a celestial triangle with the ice giant and nearby gas giant Saturn. Our satellite and Neptune share the constellation Pisces, while Saturn floats in northwestern Cetus.
By early evening, the trio stands above the southeastern horizon, and by local midnight they are high in the south. Neptune is 4° south of (below) the Moon, while Saturn is 8° to our satellite’s southeast (left). Only the latter planet is visible to the naked eye, as Neptune requires binoculars or a telescope to view. With the bright Moon nearby, the latter is your best bet, as it offers higher magnification. Through a scope, Neptune will look like a “flat,” bluish-gray star, with a tiny disk extending 2” in diameter.
Saturn is much more impressive, with its disk 19” across and its rings some 44” from end to end. Its brightest moon, Titan, is just to the planet’s northeast, while around midnight CDT fainter Rhea and Tethys are east of the ringed world and Dione stands to its west. Iapetus, around 11th magnitude, remains relatively nearby, now about 2’ southeast of the planet. It’s still a great opportunity to catch so many of Saturn’s moons huddled close together.
Sunrise: 7:19 A.M.
Sunset: 6:09 P.M.
Moonrise: 4:41 P.M.
Moonset: 4:26 A.M.
Moon Phase: Waxing gibbous (95%)
*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.
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.