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A revision is presented of the sunspot observations made by Charles Malapertfrom 1618 to 1626, studying several documentary sources that include thoseobservations. The revised accounting of the group numbers recorded by Malapertfor that period shows new information unavailable in the current sunspot groupdatabase. The average solar activity level calculated from these revisedrecords of Malapert is by almost one third greater than that calculated fromhis records included in the current group database. Comparison of the sunspotobservations made by Malapert and by other astronomers of that time with regardto the number of recorded groups and sunspot positions on the solar disk showsgood agreement. Malapert reported that he only recorded one sunspot group ineach sunspot drawing presented in Austriaca Sidera Heliocyclia (the documentarysource which includes most of the sunspot records made by Malapert), althoughhe sometimes observed several groups. Therefore, the sunspot counts obtained inthis present work on Malapert's sunspot observations represents the lower limitof the solar activity level corresponding to those records.

Sunspot observations by Charles Malapert during the period 1618-1626: a key dataset to understand solar activity before the Maunder minimum