Sh2-145

Sh2-145 is a large and faint HII region located in the constellation Cepheus. The nebula consists mainly of diffuse hydrogen emission with very little internal structure, making it difficult to observe visually. It is best captured using wide-field imaging and narrowband filters. Due to its low surface brightness, Sh2-145 is one of the more challenging and lesser-known objects in the Sharpless catalog.

Sh2‑145 is a large, low‑surface‑brightness reflection nebula containing several small emission regions. To capture all of its components properly, both RGB filters and narrowband filters would be required. The nebula itself is extremely faint: Hα performs best, SII is much weaker, and in OIII almost nothing can be detected. The blue reflection patch in the upper left is part of Sh2‑150. Sh2‑145 is rarely photographed, so only a few examples exist. The exposures were taken over two nights, each from 00:00 to 04:00, resulting in a total integration time of six hours.