This image illustrates the eastern <a href="https://en.wikipedia.org/wiki/Mare_Tranquillitatis" class="extiw" title="en:Mare Tranquillitatis">Mare Tranquillitatis</a> looking northward as seen by the crew of the <a href="https://en.wikipedia.org/wiki/Apollo_8" class="extiw" title="en:Apollo 8">Apollo 8</a> mission. In the upper right of this picture are a pair of features forming <a href="https://en.wikipedia.org/wiki/hyperbola" class="extiw" title="en:hyperbola">hyperbola</a> shapes across the <a href="https://en.wikipedia.org/wiki/lunar_mare" class="extiw" title="en:lunar mare">lunar mare</a>. The upper feature is a pair of nearly-joined <a href="https://en.wikipedia.org/wiki/rille" class="extiw" title="en:rille">rilles</a> named the <i>Rimae Cauchy</i>. The southern curve is escarpment <i><a href="https://en.wikipedia.org/wiki/Rupes_Cauchy" class="extiw" title="en:Rupes Cauchy">Rupes Cauchy</a></i>. The crater between these two features is the <a href="https://en.wikipedia.org/wiki/Cauchy_(crater)" class="extiw" title="en:Cauchy (crater)">Cauchy crater</a>, for which they are named. To the south of the scarp can be seen a pair of low <a href="https://en.wikipedia.org/wiki/lunar_dome" class="extiw" title="en:lunar dome">lunar domes</a>. The dome to the left (west) is the Cauchy Omega (ω) and the other named Cauchy Tau (τ).
NASA (image by Apollo 8)
1968
<a rel="nofollow" class="external free" href="http://www.hq.nasa.gov/office/pao/History/alsj/a410/AS8-13-2344.jpg">http://www.hq.nasa.gov/office/pao/History/alsj/a410/AS8-13-2344.jpg</a>