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Object Type: Open cluster, Emission nebula
Constellation: Cepheus
Magnitude: 3.5
Size: 170' x 140'

Visible to the naked eye under dark skies, IC 1396 consists of an open cluster surrounded by a dim emission nebula.  At the center of the cluster is the multiple star Struve 2816, which contains a magnitude 5.6 primary, along with magnitude 13.3, 7.7, and 7.8 components.  Multiple dark lanes in the nebula are visible in this image, some of which can be glimpsed in large-aperture telescopes.  The red star at the top of the image is Mu Cephei, "Herschel's Garnet Star," one of the reddest naked-eye stars (spectral class M2) in the northern half of the sky.  Mu Cephei is one of the largest stars known, with a diameter of 2.4 billion miles, or 26 astronomical units; if it were put in place of the Sun, it would extend beyond the orbit of Saturn.  It is a a variable star, with a magnitude range of 3.4-5.1.  In this image, it appears considerably brighter than Struve 2816.

Equipment: Nikkor 180mm f/2.8 lens/ST-10XME/Astrodon LRGB filters/Paramount ME
F-ratio: f/4
Exposures: RRGB: R 8 x 12 minutes, binned 1x1: G 8 x 3 minutes: B 8 x 3 minutes: GB binned 2x2
Date: September 21, 2006
Location: Landers, California, USA
Technical Notes: Individual exposures were obtained using CCDAutoPilot2 and then sigma combined. The RGB image was created in Registar 1.0. The luminance image was initially combined with the RGB image using an opacity of 50% and then again at 100% to help preserve color saturation.