With no Moon in the sky, we’re centering on M15, which stands 60° high in the southern sky around 3:30 A.M. local daylight time. (Nighttime observers can also catch this object, though it rises about an hour after sunset and continues to gain altitude all night, so the later you look, the better.)
M15 is a bright globular cluster in Pegasus. Binoculars or a telescope will show a 7’-wide ball of stars just 4.5° northwest of 2nd-magnitude Enif (Epsilon [ε] Pegasi), often depicted as the tip of the Winged Horse’s nose.
On its own, of course, M15 is a worthy target. Containing more than 100,000 stars, it is a dense cluster that is a favorite of observers. But there’s more: M15 was the first globular cluster in which astronomers found a planetary nebula, the illuminated bubble of gas and dust blown off by a dying Sun-like star. Called Pease 1, this particular planetary is great for observers with large (15 inches or more) scopes, as well as astrophotographers. If your sky is steady today and you’ve got a big scope at your disposal, give it a try — it glows around 16th magnitude just northeast of the cluster’s center. Use magnifications greater than 300x and an OIII filter to aid in spotting it, and keep in mind its compact size makes it easy to mistake for another star. Astronomy contributor Phil Harrington recommends passing the OIII filter in and out of your field of view, helping you to identify the nebula, as it stays bright when the filter dims the stars around it.
Sunrise: 5:33 A.M.
Sunset: 8:33 P.M.
Moonrise: 5:16 A.M.
Moonset: 9:26 P.M.
Moon Phase: New
*Times for sunrise, sunset, moonrise, and moonset are given in local time from 40° N 90° W. The Moon’s illumination is given at 12 P.M. local time from the same location.
For a look ahead at more upcoming sky events, check out our full Sky This Week column.
