IC 434 and friends...

NGC 2024, IC 434, NGC 2023, IC 435 and the Horsehead Nebula (B33)

Object: IC 434
Type: Emission nebula 
Constellation: Orion
Distance: 1500 light years

Date: 1st February 2020

Equipment: ATIK 460EX with EFW2, Skywatcher f5.5 Esprit 100 ED refractor, Avalon Linear mount, guiding with Lodestar X2/PHD

Subframes: 30 x 300s H-alpha, 6 x 300s each for RGB (2x2 binned), no flats/darks (hot pixel removal in Astroart).

Stellarium map showing area imaged

IC 434 is a bright emission nebula in the constellation Orion.  Discovered on February 1, 1786 by William Herschel, the nebulosity extends down for over one degree from Alnitak (zeta Orionis), the easternmost star in Orion’s Belt. 

It is part of the much larger Orion Molecular Cloud Complex, one of the most active regions of nearby stellar formation visible in the night sky, and is home to both protoplanetary discs and very young stars. Much of it is bright in infrared wavelengths due to the heat-intensive processes involved in stellar formation, though the complex contains dark nebulae, emission nebulae, reflection nebulae, and H II regions.

Just to the north of IC 434 is the Flame Nebula (NGC 2024, Sh2-277). It lies 1,500 light-years away and is illuminated by Alnitak. Additional dark gas and dust lies in front of the bright part of the nebula resulting in the dark network, appearing to permeate the glowing gas. At the centre of the Flame Nebula is a cluster of several hundred newly formed stars, discovered by the Chandra X-ray Observatory.

Annotated objects in main image

Just below NGC 2024 lies NGC 2023 (LBN 954), an emission and reflection nebula. It was discovered by William Herschel on 6 January 1785. It is four light-years in diameter, making it one of the largest reflection nebulae ever discovered. It is illuminated by the star HD 37903, the most luminous member of the stars in the Lynds 1630 molecular cloud.  A smaller reflection nebula, IC 435, lies just to the east of NGC 2023.

At the western edge of Lynds 1630, a swirl of dark nebulosity shows up against the background glow of IC 434.  This is the famous Horsehead Nebula (Barnard 33), first recorded in 1888 by Scottish astronomer Williamina Fleming on a photographic plate taken at the Harvard College Observatory. The Horsehead Nebula is approximately 1375 light years from Earth.