C4 - Iris Nebula
Caldwell 4 (NGC 7023) also known as the Iris Nebula is a diffuse nebula located within the constellation Cepheus.
C4 is best viewed during Fall, is magnitude 7*, and can be viewed with binoculars. It is 18 x 18' in size. For reference, the full moon is 30' (arc minutes) in size.
- Iris Nebula
- diffuse nebula
- 18 x 18'
- 21 01.8
- +68 12'
* The naked eye can see up to magnitude 8 objects under ideal dark sky conditions.