About the Object
IC 4592, also known as the Blue Horsehead nebula, is a reflection nebula surrounding the star system of Nu Scorpii and is also part of a much larger molecular cloud complex. The blue colors in the image are caused by Rayleigh scattering of starlight around some of the brighter stars in the image embedded in dust and gas. The red and orange sections of the image are predominantly dust clouds preferentially absorbing blue light while passing longer wavelengths. Dust particles in interstellar space are generally much smaller than those here on Earth's surface, typically ranging from 10nm to 0.1um in size making them more like particles of smoke than what we think of as dust. 

In addition to the IC 4592, the largest, brightest reflection nebula in the image, you can also see IC 4601 on the upper  right of the frame. The mechanism of scattering is the same, but with different stars scattering light off their surroundings. The bright blue star on the left edge of the image is Beta Scorpii, also known as Graffias which means "claws" in Arabic. The blue halo surrounding this star in the image is caused mostly by light scattered by the optics of the telescope itself. 

The Blue Horsehead is located at a distance of about 400 light years. This image captures a swath of sky approximately five degrees across, so the molecular cloud from which the Horsehead is formed is about 40 light years in size. 

About the Image
This picture was captured between 6/13/2023 and 6/19/2023 from Rowe, NM using a remotely operated 305mm Riccardi-Honders telescope at f/3.8. Total integration time was a little over 18 hours across three filters (RGB) and eight mosaic panels. All subs were two minutes in duration. The mount used was an AP1100GTO AE running unguided. This was my first successful attempt at such a large mosaic. Gradients can wreak havoc even under fairly dark skies with objects this low to the horizon. Most of the data were captured while the Horsehead was between 25 and 30 degrees above the horizon making it somewhat challenging to address light pollution gradients.

The camera used was a QHY600PH monochrome binned 2x2 with 50mm square Chroma RGB filters. All instruments were controlled using NINA, and APCC Pro. Image pre-processing, integration, and processing was performed in PixInsight. Photoshop was used to remove a couple of nasty reflections (arcs) near Beta and Omega Scorpii as well as to address some dark blooms that are common when using the QHY600 on bright stars. Photomerge Mosaic in PixInsight was used to combine the panels. The final image was down-sampled from ninety megapixels for internet size considerations.