NGC 6940

Also Known as: Melotte 232

Object Type: Open Cluster

Constellation: Vulpecula

Distance from Earth: 2,500 Light Years

Apparent Magnitude: 6.3

Coordinates: RA 20H 38M 26S DEC 28deg 17min 00sec

Actual Size: 85,000 light years in diameter

Apparent Dimensions: 25 arc-minutes

Discovered by: NGC 6940 was discovered by William Herschel in 1784

Description: NGC 6940 has hundreds of members. The cluster is quite scattered and in between its members are also visible field stars.
For example, two bright stars, an 8.6 mag B8III giant star at the NE edge and a 9.1 mag A0III giant at the SW corner of the cluster are too young to be true members of NGC 6940 and are probably background stars.
The brightest star (lucida) of NGC 6940 is the red giant FG Vulpeculae, a semiregular variable star whose magnitude ranges from 9.0 to 9.5 every 80 days approximately.
NGC 6940 is rich in red giants, more than 20 according to WEBDA database.
Based on the spectroscopic analysis of twelve of them, the cluster age was estimated to be 1.1 billion years.
Its metallicity is close to the one of the Sun. In NGC 6940 have been detected 8 variable stars whose variability is consistent with the delta Scuti variables.

Click Below Image(s) for Full Size:

NGC 6940 is situated north of the celestial equator and, as such, it is more easily visible from the northern hemisphere. It is best seen in the summer months.

Platesolve

NGC 6940 Open Cluster

Imaging Details
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