NGC 7023 is a reflection nebula located in the west central section of the far northern constellation of Cepheus. This nebula contains at its centre an extremely young star named V380 Cep (mag. +7.1), which is believed to have burst into life just 5,500 years ago. Since incredibly young there is plenty of local dust surrounding the star, and when starlight hits the dust it's reflected to become the visible nebula.
NGC 7023 is located 6 degrees northwest of the brightest star in Cepheus, Alderamin (α Cep - mag. +2.5) with third magnitude Alfirk (β Cep) 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. A faint eleventh magnitude barred-spiral galaxy, NGC 6951, is positioned two degrees southwest of NGC 7023.
The nebula is also known as the Iris Nebula and is number 4 in the Caldwell catalogue. It was discovered by Sir William Herschel on October 18, 1794.
NGC 7023 shines with an apparent magnitude of +6.8 and is theoretically bright enough to be visible with binoculars, but its large apparent size (18 arc minutes) and diffuse nature makes this an almost impossible task. It's also difficult to spot with 80mm (3.1-inch) or 100mm (4-inch) refractors, at best appearing as a faint, misty patch of light without detail. The best views of NGC 7023 are reserved for large scopes. With a 250mm (10-inch) or larger instrument the nebulosity is fairly easy to spot, and under good conditions a wealth of intricate details such as knots and dark patches are revealed. Of course, the true beauty of NGC 7023 is revealed in images and long exposure photographs. They show much fine detail embedded in a characteristic blue light caused by reflected starlight off dust grains.
NGC 7023 is 1,300 light-years distant and has a spatial diameter of 7 light-years. It's best seen from northern temperate locations where it appears high in the sky during October, November and December. From latitudes north of +22 degrees the nebula is circumpolar and therefore visible all year round. From southern latitudes it appears at best low down or never even rises at all.
NGC 7023 Data Table
|Object Type||Reflection Nebula|
|RA (J2000)||21h 01m 36s|
|DEC (J2000)||+68d 10m 10s|
|Apparent Size (arc mins)||18 x 18|
|Other Name||LBN 487|
|Notable Feature||Reflection nebula illuminated by mag. +7.4 star V380 Cep (SAO 19158)|