The hack is to make all lights in the neighborhood of an observatory flicker at “about 150 times per second”, and for observatories to ‘close their eyes’ when street lighting is on, giving up part of their light input (the article doesn’t tell, but I guess at least half of it. The LED lighting also will give up part of its brightness, but I think that’s less of a concern. It can easily be made brighter, if that’s needed at all)
“For the purposes of presenting moving images, the human flicker fusion threshold is usually taken between 60 and 90 Hz, though in certain cases it can be higher by an order of magnitude.”
That’s already awfully close to 150Hz, certainly if all lights you see do that, but let’s ignore that, and read on, where we find:
“In some cases, it is possible to see flicker at rates beyond 2000 Hz (2 kHz) in the case of high-speed eye movements (saccades) or object motion, via the "phantom array" effect. Fast-moving flickering objects zooming across view (either by object motion, or by eye motion such as rolling eyes), can cause a dotted or multicolored blur instead of a continuous blur, as if they were multiple objects”
and
“The flicker fusion threshold also varies between species. Pigeons have been shown to have higher threshold than humans (100 Hz vs. 75 Hz), and the same is probably true for all birds, particularly birds of prey. Many mammals have a higher proportion of rods in their retina than humans do, and it is likely that they would also have higher flicker fusion thresholds. This has been confirmed in dogs.
Research also shows that size and metabolic rate are two factors that come into play: small animals with high metabolic rate tend to have high flicker fusion thresholds.”
TLDR: I don’t think this is a good idea, especially not given that the actual problem (FTA: “But there is a downside to LEDs: They're much brighter than old-fashioned energy-guzzling light bulbs”) is easily avoided. It’s not like we couldn’t replace light bulbs with LED lighting of equal intensity (and directed in the same directions)
I doubt that’s invisible to humans, though, and am fairly sure it is visible to many animals species, including some pets. https://en.wikipedia.org/wiki/Flicker_fusion_threshold#Displ...:
“For the purposes of presenting moving images, the human flicker fusion threshold is usually taken between 60 and 90 Hz, though in certain cases it can be higher by an order of magnitude.”
That’s already awfully close to 150Hz, certainly if all lights you see do that, but let’s ignore that, and read on, where we find:
“In some cases, it is possible to see flicker at rates beyond 2000 Hz (2 kHz) in the case of high-speed eye movements (saccades) or object motion, via the "phantom array" effect. Fast-moving flickering objects zooming across view (either by object motion, or by eye motion such as rolling eyes), can cause a dotted or multicolored blur instead of a continuous blur, as if they were multiple objects”
and
“The flicker fusion threshold also varies between species. Pigeons have been shown to have higher threshold than humans (100 Hz vs. 75 Hz), and the same is probably true for all birds, particularly birds of prey. Many mammals have a higher proportion of rods in their retina than humans do, and it is likely that they would also have higher flicker fusion thresholds. This has been confirmed in dogs.
Research also shows that size and metabolic rate are two factors that come into play: small animals with high metabolic rate tend to have high flicker fusion thresholds.”
TLDR: I don’t think this is a good idea, especially not given that the actual problem (FTA: “But there is a downside to LEDs: They're much brighter than old-fashioned energy-guzzling light bulbs”) is easily avoided. It’s not like we couldn’t replace light bulbs with LED lighting of equal intensity (and directed in the same directions)