111-mile-wide Janus passes in front of the face of her much larger sister Titan in this image from Cassini, taken on March 27.

At 3,200 miles wide, Titan is one of the largest moons in the solar system, even larger than the planet Mercury. A thick atmosphere keeps its frigid and gloomy surface permanently hidden beneath orange-tinted clouds, and a high-level haze layer enshrouds it even further. In comparison Janus is barely more than a roughly-shaped chunk of rock and ice, covered in craters and gouges from eons of impacts. Janus shares an orbital path around Saturn with twin sister Epimetheus.

This image is my first attempt to combine raw images taken in separate color channels into a single “true” color composite, as instructed by Emily Lakdawalla on The Planetary Society blog. I’m pretty happy with the results…honestly I thought it would be more difficult than it was but since I’m already really familiar with Photoshop it wasn’t too hard at all, once I found three images taken in the right colors. I admit I had to fudge the smaller moon, copying it from the blue channel and pasting it into the right position on the final composite…because it was moving relative to Titan, it was getting separated into a triple-image (I chose the middle position for the final photo above.) But Titan is pretty well aligned and colored, I think. I’ll get the hang of it eventually. 🙂

Image: NASA/JPL/SSI/J. Major