Visual deep-sky observing notes and sketches by Ivan Maly
Abell 4
Abell 4, PK 144-15.1, Per. 2020-08-19, Cherry Springs, SQM 21.61-21.69. 20-inch Newtonian (F/4), ocular 8 mm. OIII filter. Round, soft edges, little concentration. Shallow arc of three stars to the S and E. [The nebula is prominent on Panstarrs g.]
