I recently encountered this phrase and was unfamiliar with it. Apparently it refers to light rays, beams of light emanating from a bright source through enough atmospheric haze or debris as to cause those beautiful rays of light: crepuscular light.
Crepuscular rays or “God rays” are sunbeams that originate when the sun is below the horizon, during twilighthours. Crepuscular rays are noticeable when the contrast between light and dark is most obvious. Crepuscular comes from the Latin word “crepusculum”, meaning twilight. Crepuscular rays usually appear orange because the path through the atmosphere at sunrise and sunset passes through up to 40 times as much air as rays from a high midday sun. Particles in the air scatter short wavelength light (blue and green) through Rayleigh scattering much more strongly than longer wavelength yellow and red light.– Wikipedia
I do not know if crepuscular rays are limited to only sun rays once the sun is below the horizon as the above definition seems to indicate or if they can also include such rays as pictured below.
I’m not sure if the photo below, of our horse Madrone in the morning sunlight, is also crepuscular light or if it is just light from a lens flare. I mean, I know it’s the latter, but is such lens flare also considered crepuscular light? Inquiring minds have to know.