Akkana Peck wrote about an uncharted lunar feature she dubbed the Lassell stripe a few years ago. Mojo pointed out "there's another a Straight Wall north of the Straight Wall" on a recent sidewalk astronomy night. I didn't have sketch material, so I marked the stripe in my Rukl map 54 (the scan below). As soon as I saw the map, I knew I had seen the mysterious stripe, even thought the crater Lassell was not visible yet. Look for this feature on the 9-day old waxing moon, when the Straight Wall is near the terminator. It's not as dark a shadow as I show on the map. It's a more subtle line: a little thicker and a little longer than the Straight Wall. Telescope 12.5-inch f5.75 Litebox reflector 16mm Nagler 114x.