In the framework of the International interdisciplinary workshop on light pollution we are organizing a facultative field trip to Oukaimeden Observatory during the night of 20 to 21 of October. Participants who will bring with them instruments to measure the sky brightness and who are interested to participate to such event are invited to contact Martin Aubé ( who will maintain the participant list. The transport will be provided by the workshop organizers. Giving the moon phase, the relevant period of observation will be from 4:25 AM (moon set) to 7:40 AM (sun rise).