The Iris Nebula (also known as NGC 7023 and

Caldwell Caldwell may refer to: People * Caldwell (surname) * Caldwell (given name) * Caldwell First Nation, a federally recognized Indian band in southern Ontario, Canada Places Great Britain * Caldwell, Derbyshire, a hamlet * Caldwell, Eas ...

4) is a bright

reflection nebula Reflection or reflexion may refer to: Science and technology * Reflection (physics), a common wave phenomenon ** Specular reflection, reflection from a smooth surface *** Mirror image, a reflection in a mirror or in water ** Signal reflection, in s ...

in the constellation Cepheus. The designation NGC 7023 refers to the

open cluster An open cluster is a type of star cluster made of up to a few thousand stars that were formed from the same giant molecular cloud and have roughly the same age. More than 1,100 open clusters have been discovered within the Milky Way galaxy, and ...

within the larger reflection nebula designated LBN 487. The nebula, which shines at magnitude +6.8, is illuminated by a magnitude +7.4 star designated SAO 19158. It is located near the Mira-type variable star T Cephei, and near the bright magnitude +3.23 variable star

Beta Cephei Beta Cephei (β Cephei, abbreviated Beta Cep, β Cep) is a triple star system of the third magnitude in the constellation of Cepheus. Based on parallax measurements obtained during the Hipparcos mission, it is approximately 690 light ...

(Alfirk). It lies 1,300

light-year A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (), or 5.88 trillion miles ().One trillion here is taken to be 101 ...

s away and is six light-years across.

Notes

References

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External links

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SEDS – NGC 7023

VizieR – NGC 7023

NED – NGC 7023

Dark Atmospheres Photography – Iris Nebula NGC 7023

See NGC 7023 in WorldWide Telescope
{{DEFAULTSORT:Iris Nebula NGC objects 004b Cepheus (constellation) Reflection nebulae Diffuse nebulae