These are images of the Flame Nebula (NGC 2024). The bright star at the top of the image is Alnitak, which sends ultraviolet light into the Flame. This knocks electrons of the masses of hydrogen gas; the glow of the nebula is mostly from the recombining electrons and hydrogen. The nebula is part of the huge Orion Molecular Cloud--a star forming region. Note also the lanes of dark gas and dust in these images. The integrations were all around 20-30 seconds long with dark frame processing enabled.