One can see the entire process of new star formation in this view of the iconic Horsehead Nebula in Orion. The blue supergiants star Sigma Orionis, which is above the field of view, is emitting intense ultraviolet radiation that is ionizing the hydrogen in the emission nebula IC 434, causing it to glow red at a wavelength of 656.28 nm. That star is also emitting fierce stellar winds that are creating wisps and streaks within the nebula and also cause it to pile up as a shock wave as it encounters the resistance of the large dark molecular dust cloud, Lynds Dark Nebula 1630. However, there are some persistent intrusions of the dark nebula into the emission nebula, such as the Horsehead Nebula itself. As the fierces stellar winds continue to apply pressure to the edges of these intrusions, the hydrogen within them becomes compressed and eventually gravity takes over and the hydrogen collapses into a newborn star.

The newborn star will emit its own fierce stellar winds that will drive away the surounding dust and star will emerge from the dark nebula. Because the surrounding dust scatters the light from the star, the surrounding area appears blue, just as Earth’s atmosphere scatters light from the Sun makes the sky appear blue, creating a blue reflection nebula. These processes are visible in the blue reflection nebula NGC 2023 at the bottom left of the image.

This image was shot completely unguided with a total exposure of over 26 hours, which is a testament to the superb tracking accuracy of the L500 mount.

Telescope/Mount: PlaneWave CDK17 on L500 mount.

Camera: SBIB STL 11000M with Baader Planetarium Ha, L, R, G, and B filters.

Exposures: Ha:L:R:G:B = 1155:175:85:85:85 minutes = 26 hours, 25 minutes total exposure.