IC434 is a bright emission nebula containing the Horsehead nebula (Barnard 33, LDN 1630). Located near the bright star Alnitak, the left star in Orion's belt, the brighter emission nebula was discovered by William Herschel on February 1st, 1786. Located approximately 1500 light-years away, the Horsehead is a dark nebula and was first noticed on a photographic plate by Williamina Flemming in 1888.
NGC2024, the Flame nebula (Sh2-277), is similarly an emission nebula located about 1350 light-years away. The nebula is illuminated by ultraviolet light from Alnitak. A dark dusty region between the glowing gas near Alnitak and Earth gives the flame its characteristic dark structure.
NGC2023 is the reflection and emission nebula located between the Horsehead and Flame in the image. Located 1467 light-years away, it is illuminated by a star HD 37903 and was discovered by Herschel on January 6th, 1785.
Nearby are reflection nebula IC435 (to the left of NGC2023) and IC 432 (just above and right of the Flame).
Acquisition:
Imaged over 5 nights in January and February 2017 from Lake St Louis, MO
Integration: 8 hours (LRGB)
Luminance: 24x600s @ 1x1 (240')
R/G/B: 16/16/16 x 300s @ 2x2 (80'/80'/80')
Equipment:
Scope: William Optics GTF 81 5 element refractor (535mm focal length)
Upgraded with Moonlite CF focuser with motor
Imager: QHY9Ms with Olivon OAG and QHYCFW2-s filter wheel
Guidecam: ASI120MM
Filters: Baader LRGB
Mount: Orion Atlas EQ-G
Processing and Software
Guiding with PHD2
Acquisition with Sequence Generator Pro
Integration and processing with PixInsight 1.8
Horsehead and Flame:
https://flic.kr/p/Ss7AahAnnotated image:
https://flic.kr/p/RrTxfzAstrobin:
http://astrob.in/286176/0/
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