NGC 7243 is a relatively young open cluster, estimated to be just over 100 million years old. It consists mainly of white and blue stars, creating a striking contrast against the background of yellow and red stars in the surrounding field. The cluster’s brightness and loose arrangement make it an attractive target for amateur astronomers and astrophotographers. Its location in the less prominent constellation of Lacerta adds to its appeal as a somewhat hidden gem in the night sky.
Names and Catalog numbers
- Caldwell 16
- NGC 7243
- Melotte 240
- Cr 448
Position and the cosmic neighborhood
NGC 7243 is situated near several notable celestial objects in the Lacerta constellation. It can be found in proximity to the naked-eye stars Alpha Lacertae and 4 Lacertae, the latter being an A-class double star.
Nice to Know
- NGC 7243 is one of the more prominent open clusters in the relatively obscure constellation Lacerta.
- The cluster’s young age of about 100 million years is reflected in its abundance of bright blue stars.
- It is visible to the naked eye under dark sky conditions, making it an accessible target for amateur astronomers.
- NGC 7243 is circumpolar for observers at higher northern latitudes, meaning it never sets below the horizon.
Brightness, distance and size
NGC 7243 shines at an apparent magnitude of +6.4, making it visible to the naked eye under dark skies and easily observable with binoculars or small telescopes. The cluster is located approximately 2,800 light-years away from Earth. While its exact physical size is not precisely determined, its apparent size spans about 21 arcminutes in the night sky, roughly equivalent to two-thirds the diameter of the full moon. This angular size, combined with its distance, suggests that NGC 7243 has a physical diameter of several light-years, typical for an open cluster of its age and composition.
