In my recent “Daylight” post I mentioned astronomical twilight and wondered how dark that was.

It was a new moon, so there was no moonlight to add brightness. Since I was up anyway for the aurora, it was a good time to see just how dark astronomical twilight is.

The light level was similar to a nearly full moon, even though the light was provided by the sun well below the horizon & not by the moon. (Moonlight is really sunlight reflecting off the moon, of course). I could clearly see a mountain miles away with my bare eyes, so there is a fair amount of light. But astronomical twilight still seemed a lot closer to “night” than to “daylight”.