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July 25: Great Square rising
Asteroid 3 Juno reaches opposition at 1 P.M. EDT. Already above the horizon at sunset and visible all night, Juno glows at 9th magnitude in the constellation Aquila the Eagle.
The Moon is nearby, now contained within the lid of Sagittarius’ Teapot. But let’s give Juno a try, one constellation to the northeast and near the tip of Aquila’s eastern wing. A telescope may be best for the effort, as it will capture more light from fainter objects, even in the light of the Moon.
The brightest star in Aquila is magnitude 0.8 Altair, in the constellation’s northern region. Early this evening, with Aquila still rising in the southeast, all you need to do is drop down toward the horizon about 11° from this star and you’ll land on 3rd-magnitude Theta (θ) Aquilae. Juno is just over 4° south of this star, passing very close to a slightly brighter (magnitude 8.7) field star, cataloged as HIP 99225 or HD 191147. Of the two similarly bright lights in your eyepiece, Juno is the northern one, moving subtly toward the southwest as the hours pass.
Sunrise: 5:53 A.M.
Sunset: 8:19 P.M.
Moonrise: 6:49 P.M.
Moonset: 2:43 A.M.
Moon Phase: Waxing gibbous (94%)
*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.
The ringed planet Saturn reaches a stationary point at 7 P.M. EDT on July 27. Located in the constellation Pisces, it is highest around sunrise, so the best time to spot it is a few hours before dawn, with the sky still dark and the gas giant well above the horizon.
Around 3 A.M. local daylight time on July 27, Saturn is roughly 40° high in the southeast, the brightest point of light here. It stands in southern Pisces, just above the lumbering constellation Cetus the Whale. Through a telescope, the planet’s disk stretches 18” across, while its rings are more than twice that: 41” across. Saturn is currently tilted by nearly 7°, showing off its south polar region and the underside of its rings.
While several 10th-magnitude moons cluster near the planet, its largest — and brightest — moon, Titan, is a bit farther away. On the morning of the 27th, it lies about 1.7’ southwest of Saturn and is moving east. It should be easy to spot; Titan will pull closer in to the planet’s southwest tomorrow morning, then sit southeast of Saturn the morning of the 29th. If you’re an early riser, try to catch it over the next few days to see orbital mechanics in motion!
The halt brings Saturn’s prograde, or eastward, motion to an end. After this evening, the ringed planet will about-face and begin moving westward, or retrograde, relative to the background stars.
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.
