Imaged the reflection nebula NGC 7023 (The Iris Nebula) on the night of September 15, 2023. NGC 7023 has an apparent magnitude (v) of 6.8 and an apparent size of ~18x18 arcmin. I was pretty excited to se I had also captured some of the nearby dark interstellar dust clouds, a first for me from my Bortle 9 skies.
Per Wikipedia (reference:
https://en.wikipedia.org/wiki/Iris_Nebula): "The
Iris Nebula (also known as
NGC 7023 and
Caldwell 4) is a bright
reflection nebula in the
constellationCepheus. The designation NGC 7023 refers to the
open cluster within the larger reflection nebula designated LBN 487.The nebula, which shines at magnitude +6.8, is illuminated by a magnitude +7.4 star designated HD 200775. It is located near the
Mira-type variable star
T Cephei, and near the bright magnitude +3.23 variable star
Beta Cephei (Alfirk). It lies 1,300
light-years away and is six light-years across."
Imaged with a William Optics GT81 at F4.7 (382 mm focal length) using Flat6A II field flattener/0.8x reducer, UVIRcut filter, and ZWO ASI 533MC Pro. Total integration time of 3 hours: 89 subs at Gain = 100 with an exposure time of 120 seconds.
All images pre-processed using Pixinsight's weighted batch pre-processing script (WBPP) to perform calibration, debayering, registration, local normalization, and integration. Drizzle integration of WBPP results to 2x. Background removed using GradXpert. Initial post-processing in Pixinsight: spectrophotometric color calibration, blur x terminator, and noise x terminator. Stretched with EZ soft stretch and then generalized hyperbolic stretch, curves adjustment, HDR transformation using EasyHDR script, dark structure enhance script, local histogram transformation, and re-sampling to 1x.
Original version: NGC 7023 OSC RGB image
Rev B: NGC 7023 OSC RGB image (starless)
Rev C: NGC 7023 OSC RGB image (inverted)
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