A vector magnetograph is a type of imaging telescope that can estimate the 3-D vector of the magnetic field on a distant body with a resolved line spectrum. ... Emission or absorption of a photon changes the magnetic moment of the atom.

What is a magnetogram used for?

A magnetogram is not a "picture" of the Sun which you might see with your eyes. Rather, it's an image taken by an instrument which can detect the strength and location of the magnetic fields on the Sun.

How does a magnetograph work?

The magnetograph works by measuring the polarization of light at various wavelength positions within a solar spectral line. ... Linear polarization provides information on the strength and direction of the magnetic field transverse to the line of sight.