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Contains:  NGC 7023, NGC7023, T Cep, VdB139
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Iris Nebula (2019), 


            Kurt Zeppetello
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Iris Nebula (2019)

Imaging telescopes or lenses: Astro-Tech AT115EDT f/7

Imaging cameras: ZWO ASI 1600MM-Cool

Mounts: Orion Atlas AZ/EQ Pro

Guiding telescopes or lenses: Agena 50mm Guide Scope with Helical Focuser

Guiding cameras: QHY-5-L-II-M Planatary & Autoguider

Focal reducers: Astro-Tech 0.8x reducer/field flattener

Software: Adobe photoshop  ·  Pleiades Astrophoto PixInsight  ·  Lightroom  ·  AstroPhotography Tools APT capture software  ·  Astronomy Tools - PS  ·  PHD Guiding

Filters: ZWO B 1.25" optimized for ASI1600  ·  ZWO G 1.25" optimized for ASI1600  ·  ZWO R 1.25" optimized for ASI1600  ·  ZWO L 1.25" optimized for ASI1600

Accessory: ZWO EAF Electronic Focuser  ·  ZWO 8x 1.25" Filter Wheel (EFW)

Dates:June 27, 2019June 28, 2019June 30, 2019July 3, 2019July 4, 2019

ZWO B 1.25" optimized for ASI1600: 59x90" (gain: 139.00) -10C bin 1x1
ZWO G 1.25" optimized for ASI1600: 57x90" (gain: 139.00) bin 1x1
ZWO L 1.25" optimized for ASI1600: 248x90" (gain: 139.00) -10C bin 1x1
ZWO R 1.25" optimized for ASI1600: 60x90" (gain: 139.00) bin 1x1

Integration: 10.6 hours

Darks: ~12

Flats: ~15

Bias: ~20

Avg. Moon age: 15.77 days

Avg. Moon phase: 12.57%

Bortle Dark-Sky Scale: 5.00

Temperature: 18.00 job: 2798192

RA center: 21h 1' 48"

DEC center: +68° 11' 34"

Pixel scale: 1.204 arcsec/pixel

Orientation: -172.017 degrees

Field radius: 0.926 degrees

Resolution: 4480x3255

Locations: Happy Frog Observatory, Monroe, Connecticut, United States

Data source: Backyard


Here lies my latest version of the Iris Nebula (NGC 7023 or Caldwell 4). It is a bright reflection nebula approximately 1300 light-years away in the constellation of Cepheus and is 6 light-years across (bright blue portion). NGC 7023 is actually the cluster within the nebula (a.k.a. LBN 487). The nebula is lit by the young central star named V380 Cep (mag. +7.1), which is believed to have burst into life just 5,500 years ago in a region containing huge amounts of dust. The bright blueish portion is due to the reflected light in the visible portion of the spectrum. Harder to pickup is the faint reddish brown outer colors resulting from dust absorbing ultraviolet light from the star and releasing it as dim reddish light. Also, researchers using infrared light detectors found that this nebula contains complex carbon molecules known as Poly Aromatic Hydrocarbons (PAHs).

This is one of my favorite reflection nebulae and is much better than my image from three years ago. I spent a lot of time trying to enhance the dark portions with blowing out the rest of the image and a special thanks goes to Astrobin user Will Czaja for recommending "dark structures enhancement in PI". The reddish dust portion was where I spent most of the time and probably 'chickened out' by not going further or more dramatic with enhancements than some of the other images I have seen.

Several dark nebula appear in this image among them is LDN 1174 just left of the center, LDN 1172 upper central, LDN 1170 near the top, and LDN 1173 just right of the center. Of course the bright yellow star T-Cep on the lower right corner has the geometric pattern from my camera but the other bright stars seem unaffected. Imaging was tough due to the unstable weather but I managed to get more by holding of an waiting for more clear nights.

Lastly, this was the second image made using the ZWO EAF focuser and the first image made using the ScopeBuggy. I have two locations in my yard to image from, one is the astronomy shed and the second is from my front lawn. The weather can changes here at the blink of an eye I got tired of the back and forth. There was some concern that it would not be stable enough for imaging but I made some modifications to it. YouTube:



Kurt Zeppetello
License: None (All rights reserved)

Sky plot

Sky plot


Iris Nebula (2019), 


            Kurt Zeppetello