Petronella Johanna de Timmerman

Petronella Johanna de Timmerman (31 January 1723, in Middelburg – 2 May 1786, in Utrecht) was a Dutch poet and scientist.

Her first publication, a poem about astronomy, was published in 1746, three years before she married Abraham Haverkamp.

After Abraham's death in 1758, she remarried in 1769 to Johann Friedrich Hennert, professor of mathematics, astronomy and philosophy. During her second marriage, she conducted scientific experiments and studied physics with her spouse. She was inducted as an honorary member of the academy ‘Kunstliefde Spaart Geen Vlijt’ in 1774.