Atmospheric Unconformity (possible True Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)

Caption NASA:"In this stunning image, the Cassini spacecraft looks at the dark side of Saturn's largest moon. The narrowing circle of light surrounding Titan is produced by Sunlight scattering through Titan's Atmosphere.
A detached, high-altitude Global Haze layer encircles Titan. North on Titan is up and rotated 10° to the right.

The image was taken with the Cassini Spacecraft narrow-angle camera on March 16, 2010 using a spectral filter sensitive to wavelengths of UltraViolet Light centered at 338 nanometers. The view was obtained at a distance of approx. 1,9 MKM (about 1,2 MMs) from Titan and at a Sun-Titan-Spacecraft, or Phase, Angle of 158°.
Image scale is roughly 11 Km (a little less than 7 miles) per pixel".