Find daily light onset

Locates the first sustained crossing above a light threshold within a day, requiring the threshold to be exceeded for a minimum duration to avoid triggering on brief artefactual spikes.

Usage

find_light_onset(trace, threshold = 1000, min_duration_minutes = 5)

Arguments

trace

An object of class luxR_trace (see light_trace()), typically spanning a single day.

threshold

Numeric scalar, illuminance threshold in lux. Default 1000.

min_duration_minutes

Numeric scalar, minimum sustained duration above threshold required, in minutes. Default 5.

Value

A POSIXct scalar giving the onset time, or NA if no qualifying onset is found.