The Iris Nebula, also NGC 7023 and Caldwell 4, is a bright reflection nebula and Caldwell object in the constellation Cepheus. NGC 7023 is actually the cluster within the nebula, LBN 487, and the nebula is lit by a magnitude +7 star, SAO 19158. It shines at magnitude +6.8. It is located near the Mira-type variable star T Cephei, and near the bright magnitude +3.23 variable star Beta Cephei (Alphirk). It lies 1,300 light-years away and is six light-years across.
- SEDS – NGC 7023
- Simbad – NGC 7023
- VizieR – NGC 7023
- NED – NGC 7023
- Dark Atmospheres Photography – Iris Nebula NGC 7023
- See NGC 7023 in WorldWide Telescope
- Iris Nebula on Articles and images