File:Iris_Nebula_-_NGC_7023_-_Caldwell_4.jpg · Wikimedia Commons · See Wikimedia Commons
Key facts
- Right ascension
- 21 01 35.60
- Declination
- +68 ° 10 ′ 10.0 ″
- Distance
- 1,300 ly
- Apparent dimensions v
- 18 ' x 18'
- Constellation
- Cepheus
- Radius
- 3 ly
- Designations
- NGC 7023 and LBN487, Caldwell 4, Cr 429
via Wikipedia infobox
~8 min read
Encyclopedic overview
The Iris Nebula (also known as NGC 7023 or Caldwell 4) is a bright reflection nebula located about 1,300 light years from Earth in the constellation of Cepheus. It is six light-years across. The nebula is illuminated by a magnitude +7.4 star designated HD 200775. It is six light-years across. The nebula was discovered in 1794 by Sir William Herschel, a astronomer, where it was then added to the New General Catalogue (NGC).
The nebula is a member of the Cepheus Flare. It is located near the Mira-type variable star T Cephei, and near the bright magnitude +3.23 variable star Beta Cephei (Alfirk). The designation NGC 7023 refers to the open cluster within the larger reflection nebula designated LBN 487.
Excerpted from Wikipedia’s “Iris Nebula” article, available under the CC BY-SA 4.0 licence.