Here is the brighter center of the nebula complex. It actually is even bigger than the photo shows.
IC 1396
Emission Nebulae
Constellation: Cepheus RA: 21h 39' Dec: +57 30'
The brightest star in the frame, at top, is mu Cephei. It is a red supergiant star with a diameter larger than the orbit of Saturn, some 2536 times the diameter of the Sun. It is one of the largest stars we know of.
It is very red colored with a B-V magnitude of 2.5. Also called Herschel's Garnet Star, and Erakis, mu Cephi is a variable star that varies in magnitude from 3.4 to 5.1 over a period of approximately 730 days. It's absolute visual magnitude is -6.7, 38,000 times brighter than the Sun.
Mu Cephei is located about 1500 light years from the Earth. ---petunia's note - the error in determining distance for this star is large. Parallax is no good at this star's distance, and it is not a true Cepheid variable; thus the distance given varies greatly according to source. Starry Night Pro software's source says 5436 ly for this star. Another source says 2700 ly.
Below is a chart showing IC 1396. The little "µ" within the nebula's outline is Mu Cephei.
