English: This image compiles the visible part of the solar intensity spectrum (left) and the corresponding linear polarization at the solar limb (right). The intensity spectrum is coloured to mimic a spectrograph observation, while the linear polarization is proportional to the brightness. The linear polarization origins from scattering processes in the solar atmosphere and peaks at the solar limb. It is usually referred to as the Second Solar Spectrum. A few spectral lines show pronounced linear polarization signals, like Ca I at 4227 Å and Sr I at 4607 Å. Additionally, the continuum is increasingly linearly polarized towards the blue part of the spectrum, where scattering is very efficient. To show more details, the polarized spectrum is saturated, indicated by the cyan color. The spectra were observed with the ZIMPOL polarimeter at the IRSOL telescope in Locarno, Switzerland.

Instrument: IRSOL 0.45-m Solar Telescope with the Zurich IMaging Polarimeter (ZIMPOL), wavelength range: 450 - 650 nm

The data for this image have been provided in electronic form by IRSOL as a compilation by Stenflo (2014), based on the atlas of Gandorfer (2000, 2002, 2005).