One of my very first astronomical photographs. This is the Orion Nebula.
The Orion Nebula—also known as Messier 42, M42, or NGC 1976—is a diffuse nebula south of Orion's Belt. It is one of the brightest nebulae and is visible to the naked eye.
M42 is approximately 1,344 light-years away, making it the closest region of massive star formation to Earth. The nebula is estimated to span 24 light-years and contain about 2,000 times the mass of the Sun.
It shines brightly in the red hydrogen-alpha spectral line, captured using a dedicated H-alpha filter.