The top row of images is comprised of digital photographs taken from Troy, N.Y. of the Feb. 21, 2008 lunar eclipse. The bottom row of images is comprised of computer simulations rendered by researchers at Rensselaer Polytechnic Institute.

Graduate student Theodore C. Yapo presented the study, titled “Rendering Lunar Eclipses,” in late May at the Graphics Interface 2009 conference. 

The appearance of lunar eclipses can vary considerably, ranging from nearly invisible jet black to deep red, rust, to bright copper-red or orange. The appearance depends on several different factors, including how sunlight is refracted and scattered in the Earth’s atmosphere. Yapo and Cutler combined and configured models for sunlight, the solar system, as well as the different layers and different effects of the Earth’s atmosphere, to develop their lunar eclipse models.

For the study, Yapo and Cutler compared digital photos of the Feb. 21, 2008, total lunar eclipse with computer-rendered models of the same eclipse. The rendered images were nearly indistinguishable from the photos.

Another model they created was a rendering of the expected 2010 lunar eclipse. Yapo said he looks forward to taking photographs of the event and comparing them to the renderings. One potential hiccup, he said, is the April eruption of Mt. Redoubt in Alaska — volcanic dust in the Earth’s stratosphere can make a lunar eclipse noticeably darker and more brown. Yapo and Cutler’s models can account for this dust, but they performed their simulation prior to the eruption, and assumed a low-dust atmosphere.