NGC 6940 is an open cluster discovered by William Herschel in 1784. It is considered the finest open cluster in the constellation Vulpecula. The cluster is nearly a billion years old, making it relatively ancient for an open cluster. NGC 6940 contains hundreds of members, including numerous red giant stars, which contribute to its visual appeal.
Names and Catalog numbers
- NGC 6940
- Melotte 232
Position and the cosmic neighborhood
NGC 6940 is situated a bit more than two degrees south-southeast of 41 Cygni and three and a half degrees southwest from 52 Cygni. The cluster is located in a rich starry field near the border with Cygnus, making it an attractive target for astrophotography. Its position north of the celestial equator makes it more easily visible from the northern hemisphere.
Nice to Know
- NGC 6940 is rich in red giants, with more than 20 identified according to the WEBDA database.
- The cluster contains FG Vulpeculae, a semiregular variable star that serves as its brightest member.
- Eight variable stars consistent with delta Scuti variables have been detected in NGC 6940.
- The cluster has been studied in soft X-rays, revealing four sources identified as cluster members, including binary stars.
Brightness, distance and size
NGC 6940 has an apparent magnitude of 6.3, making it easily visible with small binoculars. The cluster is located approximately 2,510 light-years (770 parsecs) away from Earth. While the exact size in light-years is not provided in the search results, NGC 6940 has an apparent size of 25 arcminutes in the night sky. This combination of brightness and apparent size makes NGC 6940 an attractive target for astrophotographers, offering a good balance between visibility and detail.