What does it mean that a filter is a Hydrogen-Alpha solar filter?
Solar Observing FAQA Hydrogen alpha solar filter is a filter that allows only a narrow band of wavelengths through, in this case those wavelengths that correspond to the center of the red hydrogen-alpha spectral line at 6562.8 angstroms. While white light observers see the solar photosphere, hydrogen-alpha observers see the solar chromosphere. For good chromospheric detail, a hydrogen-alpha solar filter must perform with a sub-angstrom bandpass at the eyepiece end.
