The Iris Nebula (also known as NGC 7023 and Caldwell 4) is a bright reflection nebula in the constellation Cepheus. It is a small, poor open star cluster enveloped by a faint dusty nebula (LBN 487). It was discovered on 18 October 1794 by the German-British astronomer William Herschel. Dreyer described NGC 7023 as a 7th magnitude star embedded in a very faint but large nebula. The nickname Iris Nebula refers to the blue flowers of the iris (Iris versicolor) and not the iris of the eye, because of their color and shape.
Object Designations: NGC 7023 and Caldwell 4
Also known as:
Constellation: Cepheus
Object Type: open cluster
Distance: 1300 light-years away
Magnitude: 6.8
Discovery: Sir William Herschel in 1794
This final image is:
40 – 4 minute subs at 100 gain – no filter – just over 2.5 hours of integration
I processed the images using Pixinsight using:
Blink to clear out low quality images
Weighted Batch Balance
SpectroPhotometricCalibration
AutomaticBackgroundExtractor
BlurExterminator
NoiseExterminator
GeneralizedHyperbolicStrectch
ColorCalibration on both versions
StarXTerminator
Curves on both versions using other version as mask
Pixmath to put stars back with both images.
