Hydrogen alpha (Ha) imaging is done through an Ha filter. Hydrogen alpha is a specific wavelength of red light that measures 656.28nm and cannot be detected by the human eye. Hydrogen alpha is highly abundant in space and is the brightest wavelength in stellar astronomy.
Hydrogen alpha filters allows for great detail to emerge from emission nebulas and when added to color images gives great detail to a final image.
Narrowband imaging is ideal for those of us imaging from light polluted skies. Since the Baader Planetarium 7nm Ha filter, used here, blocks out all light except hydrogen-alpha emissions, one can get fine detail without the sensor becoming washed out from the glowing sky.
© Coates Astrophotography