Visit an aquarium, planetarium, rainforest, and natural history museum—all under one living roof.
Planet Watch is the Morrison Planetarium's guide to planetary activity for October through December 2017.
The nearest planet to the Sun is at superior conjunction on October 8, meaning it's on the other side of the Sun from Earth and passing behind it from our point of view. That also means it's too close to the Sun's glare to be seen until maybe late-November, when it's at greatest eastern elongation on the 24th and sets after sunset. However, even though it's separated from the Sun by 22 degrees at that time, the very shallow angle between the ecliptic and the horizon still makes Mercury very difficult to see, very low in the southwest after sunset. The littlest planet reaches inferior conjunction on December 13, emerging in the predawn sky late in the month. Its close encounters with the Moon this season are all likely too close to the Sun to be seen on the evenings of October 19 and November 20, and again on the morning of December 17.
The brightest of the planets is a morning object this season, rising in the east before the Sun but gradually retreating into the glow of twilight as the planet inexorably moves in its orbit to the other side of the Sun from Earth. It will reach superior conjunction in January, so we'll see it rise later and later, inching closer to the Sun each morning. Venus passes very close to Mars on the morning of October 5, approaching to about a fifth of a degree. On the morning of November 13, it passes about a third of a degree from Jupiter, soon after which Venus becomes increasingly difficult to see in the growing glow. The waning crescent Moon passes nearby on the mornings of October 17 and 18 and November 16 and 17, although the latter will be a challenge. The Moon's pass on December 17 is washed from view by the Sun's glare.
Like Venus, the Red Planet is a morning object this season, rising in the east before dawn, although from morning to morning, it climbs gradually higher out of the twilight and becomes easier to see as Venus disappears into it. Don't miss the very close encounter between the two on the morning of October 5. As Mars creeps eastward against the stars, it moves from Leo the Lion into Virgo the Maiden, the waning crescent Moon passes nearby on the mornings of October 17 (when Venus is still very nearby, so don't miss it), November 14 and 15, and December 13.
Lost in the Sun's glare at the beginning of October, the largest of the planets passes conjunction on October 26 and passes into the morning sky, but it doesn't become visible until about mid-November, when it climbs far enough out of the twilight to be seen against the stars of Virgo the Maiden. On November 13, Jupiter and Venus rise very close together (only a third of a degree apart) an hour in the southeast before the Sun—a challenge in the growing predawn glow, so binoculars or a telescope will help. The Moon's pass near Jupiter on October 19 is washed from view by the Sun's glare, but encounters between the two on the mornings of November 16 and December 14 are better-placed for viewing in the southeast just before dawn.
The Ringed Planet is low in the southwest just after sunset as October begins, against the stars of Ophiuchus the Serpent-Bearer, where it lingers until about mid-November, when it crosses the border into Sagittarius the Archer. The seasonal rotation of the sky causes Saturn to gradually shift westward, descending toward the glow of the setting Sun and becoming obscured from view by late-November. The Moon can be seen passing near Saturn on the nights of October 23 and 24 and November 20. Their encounter on December 18 is lost in the Sun's glow. Saturn reaches conjunction on December 21, passing behind the Sun and moving into the morning sky.
Created by Morrison Planetarium staff, these go-to resources cover important events occurring in our Universe.
The Academy's Benjamin Dean lecture series hosts the world's leading experts in astronomy, astrophysics, and more.
Morrison Planetarium is open for Thursday NightLife events, featuring special shows and presentations.
Download the Morrison Planetarium's 2017 Pocket Almanac to stay up-to-date on eclipses, meteor showers, satellite spottings, and more.