Key Takeaways:
- The autumnal equinox occurs at 2:19 P.M. EDT, marking the beginning of astronomical autumn in the Northern Hemisphere and spring in the Southern Hemisphere, with equal sunlight distribution across both hemispheres.
- The Double Cluster in Perseus (NGC 869 and NGC 884), approximately 4.5° west-northwest of Eta Persei, is a prominent celestial object observable in autumn.
- NGC 869 and NGC 884 are open clusters of approximately 4th magnitude, each spanning about half a degree; NGC 869 contains more visible stars than NGC 884.
- Specific times for sunrise (6:46 A.M.), sunset (6:56 P.M.), moonrise (7:35 A.M.), and moonset (7:12 P.M.) are provided, along with a moon phase description (Waxing crescent, 1%) for a location at 40° N 90° W.
The autumnal equinox occurs at 2:19 P.M. EDT. On this date, the Sun appears directly above the equator and the Northern and Southern hemispheres receive the same amount of sunlight. The autumnal equinox also officially brings the Northern Hemisphere summer to an end and begins astronomical autumn, while bringing the end of winter in the Southern Hemisphere and beginning astronomical spring.
One of autumn’s showpiece objects is the Double Cluster in Perseus. This two-for-one deal comprises open clusters NGC 869 and NGC 884, which lie about half a degree apart in northwestern Perseus. To find them, look about 4.5° west-northwest of 4th-magnitude Eta (η) Persei. This region is 40° high in the northeast around 10 P.M. local daylight time.
Both clusters glow around 4th magnitude and cover half a degree each. You can view them together at low power, such as through binoculars or a finder scope, or take your time with each individually at higher magnification. NGC 869 is the westernmost cluster, while NGC 884 lies due east of NGC 869. NGC 869 is slightly richer, with more stars visible than its counterpart at the same magnification. But NGC 884 is home to RS Persei, a red supergiant star near the center of the cluster whose brightness varies between 8th and 10th magnitude.
Sunrise: 6:46 A.M.
Sunset: 6:56 P.M.
Moonrise: 7:35 A.M.
Moonset: 7:12 P.M.
Moon Phase: Waxing crescent (1%)
*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.
