*** USET sunspot drawing *** The Uccle Solar Equatorial Table (USET)
facility at the Royal Observatory of Belgium has gathered an
uninterrupted series of sunspot drawings since year 1941. This
collection continues to be updated when weather permits. This table
provides information about these drawings.
*** USET Groups *** Values in the USET sunspot group catalog are
derived from the solar drawings obtained by the Uccle Solar Equatorial
Table (USET) facility that is located at the Royal Observatory of
Belgium. The USET sunspot group catalog covers 82 years of
observations in 2021, and is updated every day. A home-made software
(DigiSun) written in Python is used to derive quantities such as
location and areas from the sunspot drawings.
