image by Mike Wirths, Baja California, Mexico<br /><br />Rilles that run east to west usually aren't very visible because there aren't shadows cast filling their floors. According to Mike there is lively debate in some forums about what it takes to see this elusive Sheepshanks Rille. Well, Mike's 18" does a good job, as did Paolo Lazzarotti's 10" telescope. The rille runs through an older lava - notice the smooth, more mare ridged in the south half of the image. Whatever the force was that led to the rille's formation, it was apparently not oparating when the new lavas were laid down for few rilles cut them.<br /><br />Chuck Wood<br /><br />Technical Details<br />Jan 29, 2012. 18" Starmaster dob (Zambuto optics) a Lumenera Infinity 2-2 camera, 4X's televue Powermate barlow, an R/IR filter. Processed with AviStack and PS CS.