Blue hour is the period of twilight during dawn each morning and dusk each evening when the sun is a significant distance below the horizon and the residual, indirect sunlight takes on a predominantly blue hue. This effect is caused by the relative diffusibility of short blue wavelengths of light versus the longer red wavelengths. During the blue “hour” (typically the period is about 40 minutes in length), red light passes straight into space while blue light is scattered in the atmosphere and therefore reaches the earth’s surface. Because of the quality of the light, this period is treasured by artists.
Yes. I’m not actually that smart to write such nice lengthy sentences, explaining visual occurrences happening in nature on our little blue planet. Therefore I’m using whats already written on wiki page to explain for those who don’t yet know what blue hour is. If you like night/long exposure photography this is the time you want to have your tripod and camera ready.
Idea for this was to catch light left by passing trains during previously mentioned blue hour.