Other Names: Caldwell 4
Optics: Borg Astrograph 101ED at f/4.1
Mount: Atlas EQG using The Sky6 and EQMOD
Camera: Canon EOS 50D [ UV/IR filter modification by Hap Griffin ]
Filters: IDAS Light Pollution Suppression (LPS) Filter
Exposure: 150 Mins [30 x 300s at ISO 800]
Accessories: Auto guided with Borg 45ED and Orion Starshoot Auto guider using PHD
Location: Calgary, AB
Date: September 12th, 2010
Notes: Processing: Image acquisition with Maxim DSLR. Image calibration, align, and combine in Maxim DSLR. Levels, curves, Noise Ninja, crop and resize in Photoshop.
Calibrated w/10 Darks, 40 Bias, 40 Flats using light box, Ambient temperature was +4 to +6C.

The Iris Nebula, also NGC 7023 and Caldwell 4, is a bright reflection nebula and Caldwell object in the constellation Cepheus. NGC 7023 is actually the cluster within the nebula, LBN 487, and the nebula is lit by a magnitude +7 star, SAO 19158.[1] It shines at magnitude +6.8. It is located near the Mira-type variable star T Cephei, and near the bright magnitude +3.23 variable star Beta Cephei (Alphirk). It lies 1,300 light-years away and is six light-years across.[2