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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 orange star in the upper left 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 300mm f/4 lens/STL-11000M/Astrodon LRGB filters/Paramount ME
F-ratio: f/5.6
Exposures: RRGB: R 16 x 20 minutes: G 12 x 6 minutes: B 12 x 6 minutes: GB binned 2x2
Date: September 4, 2010
Location: Landers, California, USA
Technical Notes: Individual exposures were dithered using CCDAutopilot2 and then sigma combined. The RGB image was created in Registar 1.0. Reduce Noise and Gaussian Blur were applied to the RGB image. A high-pass filter of 4 pixels was applied to the bright portions of the luminance image. A copy of the RGB image was combined with the original using Soft Light to enhance color saturation.