Generates a listing of all lighting events. Lighting events are start and end of periods of full lighting (sunlight), partial lighting (penumbra) and periods of zero lighting (umbra). Note that the Lighting Times data provider reports all computed penumbra intervals, which means that if umbra exists, then two penumbra intervals, each with its own start and stop times, is reported--one before and one after the umbra interval. So, if lighting times that start in umbra are generated, then the first reported penumbra interval corresponds to the times that follow after the first umbra, and the penumbra interval prior to the first umbra is not reported.