Image: These pĥotographs were shot on November 9, 2019 during a a visit of an observatory station of the margins of rain-forests in Central Sulawesi province, south of Palu city. The station was installed as part of a research project conducted by universities of Palu and Gottingen. The photos show the towers used by researchers. These visits were organized with the support of professor Aiyen Tjoa, who invited me for giving seminars at the university of Palu.