Iris Nebula

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Iris Nebula
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
See also: Lists of nebulae

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.[1] 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.[2]


  1. ^ Perkins, Philip (2005). "NGC 7023". Retrieved 2008-08-06. 
  2. ^ Nemiroff, R.; Bonnell, J., eds. (2004-11-04). "NGC 7023: The Iris Nebula". Astronomy Picture of the Day. NASA. Retrieved 2008-08-06. 


  • Pasachoff, Jay M. (2000). "Atlas of the Sky". Stars and Planets. New York, New York: Peterson Field Guides. pp. 578 pg. ISBN 0-395-93432-X. 
  • Caldwell-Moore, Sir Patrick (2003). Firefly Atlas of the Universe. Firefly Books Limited. ISBN 1-55297-819-2. 

External links[edit]

RGB image of The Iris Nebula NGC 7023 taken with a 5" apochromatic refractor and a DSLR camera
Map showing location of NGC 7023 (Roberto Mura)

Coordinates: Sky map 21h 01m 36s, +68° 09′ 48″