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An ancient ball of stars, globular cluster NGC 5466 is visible in the early-morning sky, during the dark window between moonset and dawn.
NGC 5466 is a loose globular cluster with relatively few stars and a low surface brightness, making it a challenge for binocular observers. Credit: MARTIN C. GERMANO.
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January 27: The Moon, the Pleiades, and Uranus
There’s plenty to view in the early-morning sky, especially with no Moon visible before dawn.
Although anchored by the bright star Arcturus, the constellation Boötes is relatively devoid of bright deep-sky treasures. Nonetheless, without the Moon to cast its light over the sky, the brightest of its deep-sky trove — globular cluster NGC 5466 — is within reach.
Shining at magnitude 9.1, this ancient ball of stars is quite compact, spanning just 11’. You can find it about 9.6° north-northwest of Arcturus, near Boötes’ border with neighboring Canes Venatici. Discovered in 1784, NGC 5466 is some 53,000 light-years distant. Astronomy contributor and longtime columnist Phil Harrington recommends looking for the cluster as a dim, gray glow just west of a slightly brighter, 7th-magnitude field star. He recommends seeking out the darkest (least light-polluted) skies you can, especially if you’re trying to net this one with binoculars. Telescopic observers will have an easier time, although dark skies are still advantageous, bringing out more of the cluster’s stars.
Sunrise: 7:12 A.M.
Sunset: 5:15 P.M.
Moonrise: 12:28 P.M.
Moonset: 3:28 A.M.
Moon Phase: Waxing gibbous (82%)
*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.