Category Archives: Stray light

220. Stray Light Correction applied to HMI Data

Contributed by A.A. Norton. Posted on February 7, 2026

We report a point spread function (PSF) and deconvolution procedure to remove stray light from the Helioseismic and Magnetic Imager (HMI) data. The deconvolution uses a Richardson-Lucy algorithm and takes less than one second per full-disk image. In 2018, the HMI team began providing full-disk, stray-light-corrected data daily. The results, on average, show decreases in umbral continuum intensity, a doubling of the granulation intensity contrast, increases in the total field strength, most notably in plage by ∼1.4–2.5 the original value, and a partial correction for the convective blueshift.