The Sky Today on Monday, August 17: Mars at Gemini’s feet

Mars is moving slowly through the Twins, passing bright stars Eta and Mu Geminorum in the early-morning sky. | Published: August 17, 2026 On the 17th, Mars sits due north of Eta (η) Geminorum, forming an upside-down capital L shape with that star and nearby Mu (μ) Geminorum. Credit: Stellarium Looking for a sky event this week? Check out our full Sky This Week column. August 16: The Moon hangs with Venus Mars has been making its way eastward through the constellation Gemini, pulling away from open cluster M35 and approaching the two bright stars Eta (η) and Mu (μ) Geminorum. Eta shines at magnitude 3.3 and Mu at magnitude 2.9; both are fainter than 1st-magnitude Mars. Check out the view in the early-morning sky today, when Mars sits just over 1° north of Eta Gem, to its upper left in the sky as this region rises. By 5 A.M. they are roughly 30° high in the east, easy to pick out shortly before twilight begins to brighten the sky. This is a great chance to see for yourself our solar system in motion. Eta and Mu are excellent visual anchor points against which to measure the motion of Mars across the sky. Step outside at the same time over the next two days, and you’ll see that by the 19th, Mars has moved to assume a similar position some 1° north of Mu, now standing to that star’s upper left. Sunrise: 6:13 A.M.Sunset: 7:54 P.M.Moonrise: 11:42 A.M.Moonset: 10:10 P.M.Moon Phase: Waxing crescent (31%)*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.