Abell 4

Abell 4 is a faint planetary nebula located in the constellation Perseus. It is part of the Abell catalog of planetary nebulae compiled by George Abell in 1966. The nebula shows a subtle ring-like structure with delicate outer filaments, illuminated by a hot central star that ionizes the surrounding gas. Due to its low surface brightness, Abell 4 is best captured using narrowband filters such as Hα and OIII. The nebula lies in a dense star field, making it an attractive target for astrophotographers who enjoy imaging challenging and lesser-known objects.