An Etymological Dictionary of Astronomy and Astrophysics
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A → reflection nebula located in the constellation → Cepheus at a distance of 1,300 → light-years. It was discovered by Sir William Herschel on October 18, 1794. The nebula, also known as the → Iris Nebula and → Caldwell 4, is about 6 light-years across. At the center of NGC 7023 lies an extremely young star named V380 Cep or SAO 19158 (mag. +7.1), which is associated with plenty of local dust. NGC 7023 is located 6 degrees northwest of the brightest star in Cepheus, Alderamin (α Cep - mag. +2.5) with third magnitude Alfirk (Beta Cephei) positioned about 3.5 degrees to the northeast. Only a degree east-northeast of NGC 7023 is Mira type variable star T Cep, which fluctuates between magnitudes +5.2 and +11.3 over a period of 388.14 days.

7023, a serial number in the → New General Catalogue.