Star Trails Viewed from Inside a Cave

April 20, 2021


Photographer: Kevin Saragozza 
Summary Author: Kevin Saragozza; Jim Foster

The image above shows star trails as observed from inside a small cave, close near the coast of Sicily, near Syracuse (Italy). This cave overlooks a rock formation called Two Brothers.

I let my camera shoot with an intervalometer in order to gauge the Earth's rotation and create the cosmic drawing. But why are these trails colored and not simply white? By setting a low ISO sensitivity, I allowed the sensor to read the colors of the stars. However, stars have intrinsic colors, represented by the wavelength of their radiation -- the greater the wavelength, the redder the color. The wavelength of the radiation emitted is governed by the star’s surface (photosphere) temperature; the hottest stars appear white and blue (10,000-30,000 K), cooler stars are yellow, orange and red (2,700-3,800 K). It should be noted that the redness of the trails near the top of the cave is a result of chromatic aberration. Photos taken on February 20, 2021.

Photo Details: Sony a7iii camera; Samyang 14mm lens; 2.8; 25 second exposure; f/3.5; 14 mm; ISO 640; (190 shots)