The Color image is a HaLRGB sequence of 6+21+15+15+15 frames of 600s each, taken on December 2017 with the GSO telescope and the ASI1600 CCD. Total exposition time of 12 hr.
The mono image is a Ha stack of 23 frames of 1800s each. It was taken in December 2016 with the FSQ telescope and the QHY90A CCD. Total exposition time 11hr 30m.
The Horsehead Nebula (also known as Barnard 33) is a small dark nebula in the constellation Orion.The nebula is located just to the south of Alnitak, the easternmost star of Orion’s Belt, and is part of the much larger Orion Molecular Cloud Complex. It appears within the southern region of the dense dust cloud known as Lynds 1630, along the edge of the much larger, active star-forming H II region called IC 434.
The Horsehead Nebula is approximately 422 parsecs or 1375 light years from Earth. It is one of the most identifiable nebulae because of its resemblance to a horse’s head.
The nebula was first recorded in 1888 by Scottish astronomer Williamina Fleming on a photographic plate taken at the Harvard College Observatory. One of the first descriptions was made by E.E. Barnard, describing it as: “Dark mass, diam. 4′, on nebulous strip extending south from ζ Orionis.”, cataloguing the dark nebula as Barnard 33. (Wikipedia)