The Iris Nebula (also known as NGC 7023 and Caldwell 4) is a bright reflection nebula in the constellation Cepheus. The designation NGC 7023 refers to the open cluster within the larger reflection nebula designated LBN 487.
| Reflection nebula | |
|---|---|
 Iris Nebula (NGC 7023 and LBN487) | |
| Observation data: J2000.0 epoch | |
| Right ascension | 21h 01m 35.60s |
| Declination | +68° 10′ 10.0″ |
| Distance | 1,300 ly |
| Apparent magnitude (V) | 6.8 |
| Apparent dimensions (V) | 18' x 18' |
| Constellation | Cepheus |
| Physical characteristics | |
| Radius | 3 ly |
| Designations | NGC 7023 and LBN487, Caldwell 4, Cr 429 |
The nebula, which shines at magnitude +6.8, is illuminated by a magnitude +7.4 star designated HD 200775.[1] It is located near the Mira-type variable star T Cephei, and near the bright magnitude +3.23 variable star Beta Cephei (Alfirk). It lies 1,300 light-years away and is six light-years across.[2]
Notes edit
- ^ Perkins, Philip (2005). "NGC 7023". astrocruise.com. Archived from the original on 2008-05-18. Retrieved 2008-08-06.
- ^ Nemiroff, R.; Bonnell, J., eds. (2004-11-04). "NGC 7023: The Iris Nebula". Astronomy Picture of the Day. NASA. Retrieved 2008-08-06.
References edit
- Pasachoff, Jay M. (2000). "Atlas of the Sky". Stars and Planets. New York, New York: Peterson Field Guides. pp. 578 pg. ISBN 978-0-395-93432-6.
- Caldwell-Moore, Sir Patrick (2003). Firefly Atlas of the Universe. Firefly Books Limited. ISBN 978-1-55297-819-1.
External links edit
Wikimedia Commons has media related to NGC 7023.
- "NGC 7023". SIMBAD. Centre de données astronomiques de Strasbourg.
- SEDS – NGC 7023
- VizieR – NGC 7023
- NED – NGC 7023
- Dark Atmospheres Photography – Iris Nebula NGC 7023
- See NGC 7023 in WorldWide Telescope
- Iris Nebula on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images