H-alpha (Hα) is a specific deep-red visible spectral line in the Balmer series with a wavelength of 656.28 nm in air and 656.46 nm in vacuum; it occurs when a hydrogen electron falls from its third to second lowest energy level. H-alpha light is the brightest hydrogen line in the visible spectral range. It is important to astronomers as it is emitted by many emission nebulae and can be used to observe features in the Sun’s atmosphere, including solar prominences and the chromosphere.
This kind of photography requires a special filter that is quite expensive and the narrower is the bandwidth more expensive is the filter. A complete telescope for H-Alpha exists for amateur photography. I have been lucky to use one of this equipment for a short time.
It is really very difficult to take beautiful photos of the sun with this technique. I did my best but results are far from acceptable one. Anyway, here there are some attempts to take the sun in H-alpha.