  Near all-sky imaging photometry was performed from a boat on the Gulf of
Aqaba to measure the night sky brightness in a coastal environment. The boat
was not anchored, and therefore drifted and rocked. The camera was mounted on a
tripod without any inertia/motion stabilization. A commercial digital single
lens reflex (DSLR) camera and fisheye lens were used with ISO setting of 6400,
with the exposure time varied between 0.5 s and 5 s. We find that despite
movement of the vessel the measurements produce quantitatively comparable
results apart from saturation effects. We discuss the potential and limitations
of this method for mapping light pollution in marine and freshwater systems.
This work represents the proof of concept that all-sky photometry with a
commercial DSLR camera is a viable tool to determine light pollution in an
ecological context from a moving boat.
