A photograph of the Sun taken through a filter with a particular wavelength range (bandpass), which is usually narrow and centred on part of some prominent spectral line. At visible wavelengths this is typically a Fraunhofer line such as Ηα‎, and the filter used is of the birefringent (Lyot) or etalon type that can be tuned to different parts of the spectral line. At extreme ultraviolet wavelengths multilayer mirror coatings can be used to give narrow bandpasses of 1–2 nm that can be tuned to strong coronal emission lines.