Moontrail -- Full Moon Rising Over Skiathos Island, Greece

June 04, 2013

Moonrails (2)

Photographer: Nikos Paschalis; Nikos's Web site
Summary Authors: Nikos Paschalis; Jim Foster

The image above is a time lapse of the full Moon rising over Skiathos Island (in the background), Greece. It's composed of approximately 20 frames taken 30 seconds apart on the evening of April 25, 2013. Note that the Moon subtends the same angle of the sky (1/2 degree) during its rise -- it's not any bigger when it breaks the horizon than it is when well up in the sky. However, the color of the Moon does change as moonrise progresses from red to orange to yellow to white. These color changes are attributed to changes in the path length of moonlight that reaches our eyes. Red colors (long wavelengths of visible light) result from the longer path lengths when the Moon is very low in the sky. As the Moon rises higher and higher, our atmosphere scatters the longer wavelengths about as much as the shorter wavelengths, so the Moon appears white.