Another reason to point lights down

‘Skyward light, wayward light’, this blog, December 14, 2022:

One of the simplest ways [to prevent light pollution] is in fact to have no public lighting installation that casts light upward, into the sky, but keeps it all facing down. Doing this will subtract the installation’s contribution to light pollution, improve energy-use efficiency by not ‘wasting’ any light thrown upwards and reduce the power consumed by limiting it to that required to illuminate only what needs to be illuminated, together with surfaces that limit the amount of light scattered upward.

Add to this…

‘Why Are Insects Drawn to Light? A Perennial Question Gets a New Answer.’, New York Times, April 27, 2023:

A team led by biologists Samuel Fabian at Imperial College London and Yash Sondhi at Florida International University argue that when many insects see a bright light at night, they believe they’ve found the direction of the sky and attempt to orient themselves along an up-and-down axis. …

The new study also offers a hint of how to mitigate the effect … The research team found that insects seem least affected when they fly under lights that are projected straight down, as opposed to lights that shine upward or that have been mounted horizontally. This finding dovetails with longstanding advice from researchers to limit light pollution by using downward pointing light fixtures that illuminate only the nearby ground