Date Posted: 7/28/2026
Date Taken: 8/14/2015, 8/16/2015
Scope: Planewave CDK 12.5 f/8, 2541mm
Camera: SBIG STL-11000 with Astrodon Tru-Balance E-Series Gen2 filters
Temp: -15C
Mount: Losmandy Titan
Guiding: SSAG, Celestron 80mm guide scope, 600mm.
Exposure: LRGB 100:70:70:65 All subs 5min. Luminance unbinned, RGB binned 2x2.

Calibrated and Stacked with CCDStack2; RGB combine and DDP with MaximDL. Processed with CS4.

NGC 7023, a.k.a the Iris Nebula, is located 1300 light years away in Cepheus. It is a combination reflection and dark nebula. The brighter central portion consists of gas and dust illuminated by the bright central star. The outer regions are dense enough to block the light from background stars, making them dark nebula as well. The cavity to the immediate left of the central portion makes this obvious; it is a window allowing us to peer beyond the nebula to the background stars beyond.

This is a partial re-process of an image taken in 2015, to show more of the extended dark nebula.