To account for the transition from 23∶59 to 00∶00 h (midnight) in our analyses and thus avoid the potential difference between photographs taken immediately prior to and after midnight we marked the change between days by setting 21∶00 h (approximately sunset) as 00∶00 h.
![[This page as RDF]](http://data.gesis.org/somesci/static/rdf-icon.gif){kind=icon}