January 5, 2026: Bright Jupiter passes Castor in Gemini as it nears opposition. See where to find the planet each evening and how its retrograde motion becomes easy to observe.
by Jeffrey L. Hunt
Chicago, Illinois: Sunrise, 7:18 a.m. CST; Sunset, 4:34 p.m. CST. Times are calculated by the US Naval Observatory’s MICA computer program. Check local sources for sunrise and sunset times.
Daylight slowly grows at Chicago’s latitude. Today it spans 9 hours, 16 minutes. Sunrise occurs at its latest time of the season and continues through January 10th.
Bright Jupiter passes Gemini’s Castor in a wide conjunction, measuring 9.8°. With brilliant Venus nearing superior conjunction on the sun’s far side, Jupiter is the brightest starlike body in the sky tonight, over three times brighter than Sirius, the night’s brightest star. To the unaided eye, Jupiter resembles a star, while through a telescope its features are visible.
Jupiter Retrogrades
Jupiter nears opposition, when Earth passes between the sun and the planet on the 10th. As Earth overtakes an outer planet — one farther from the sun than Earth — the line of sight from our planet to Jupiter, extended to the distant stars, appears to stop moving eastward and then shifts westward. The planet never stops moving; this is an illusion created as Earth overtakes and passes Jupiter.
As opposition approaches, the apparent westward movement reaches its maximum rate, so that night-to-night changes in Jupiter’s place in front of the stars are easy to see.
Find Jupiter in the Eastern Sky After Sunset
Jupiter rises after sunset. Step outside about three hours after sundown — not so late with early sunsets — and look into the eastern sky. Jupiter is the bright star about one-third of the way from the eastern horizon to overhead. Pollux is 7.0° to the upper left, while Castor is farther above. Jupiter passed Pollux nearly a month ago, with a separation slightly closer than tonight’s gap.
Pollux and Castor are far north of the plane of the solar system (the ecliptic), but they are reasonably bright stars and serve as guideposts along it. They are the brightest stars between Taurus’ Aldebaran and Leo’s Regulus, a span of over 70°.
As the night progresses, Jupiter is high in the south near midnight and in the west-northwest tomorrow morning.
Look each clear evening to see Jupiter’s changing place in front of the Gemini Twins. Retrograde ends during mid-March.
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