NGC 2024 - Flame Nebula, IC 434 and Banard 33 - Horsehead NebulaThe region around Zeta Orionis is full of interesting objects. There is NGC 2024, also known as Flame Nebula, which is an emission nebula, about 1500 ly away. It was discovered by F.W. Herschel in 1786[1]. South of Zeta Orionis we find IC 434, a thin, yet bright emission nebula alsodiscovered by Herschel. It would not be that often photographed if it was not for Banard 33, which lies directly in front of IC 434 and gives rise to the name Horsehead nebula. According to Robert Burnham jr. it was most likely discovered by E. Pickerring as early as 1889. The horsehead is definitely visible on a plate made in 1900[2]. However, it seems that it was E. Banard who realized its importance as dark nebula and catalogued it as number 33 in his catalogue of dark nebulae. In this illustrious surrondings we also find NGC 2023, a small emission/reflection nebula just south of the flame and north-east of the horse. And somewhat more to the south-east we find another hazy patch, which turns out to be the reflection nebula IC 435 [3]. And yes, the bright blue patch on the image is Alnitak (Zeta Orionis), a mag 2 star which makes imaging and observing that region that much easier. The second image is a visualisation with a strongly upped red constrast. The third one has a different color balancing and strong contrast. 
References:[1] de.wikipedia.org/wiki/Flammennebel (german)[2] Burnhams Astronomical Handbook, vol. 2 [3] Uranometria 2000, Craig & Bonnano |
