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On Nov. 7, 2018 for just under an hour, SDO viewed a lunar transit, when the Moon partially blocked SDO's view of the Sun. At its peak about 44% of the Sun was covered. In this view, the Sun was observed in extreme ultraviolet light and, as is customary, been given false color. SDO's orbit gives it two three-week periods per year when either the Earth or the Moon cross in front of the Sun. These transits provide scientific value as well: The sharp edge of the lunar limb helps researchers measure how light diffracts around the telescope's optics and filter support grids, allowing scientists to …
