Neison's map of the eastern rille
shows five pits along its length, but none are in Madler's.
This 11-kilometer-wide rimless pit resides at the juncture of the two arms of a rille
known as Rima Hyginus, in the east end of Sinus Medii.
In these cases, ash erupted from a rille
or a V-shaped depression with tapered ends.
Some of us in the Lehigh Valley Amateur Astronomical Society dubbed it "the Teardrop Rille
" due to its droplike look.
In fact, the floor fractured, producing a delicate rille
where the lower half of the crater tilted inward.
, such as Hadley Rille
, mark locations where rapidly flowing lavas cut winding channels.
When the seeing is excellent, I can occasionally spy a thin rille
that bisects the crater floor from east to west.
At the telescope you can observe that the end of the rille
Rima Hyginus abruptly stops when it reaches the southeast edge of Mare Vaporum, showing that those lavas are younger than the rille
But no vents are visible, even in high-resolution LRO images, so the explosive activity that laid down the dark deposits probably came from eruptions along the rille
's 300-km length.
Rima Sirsalis is a straight rille
that has a surprisingly big bend near the crater De Vico A.
Very close to the mountain scarp is Hadley Rille
. The Apollo crew landed near the north end of the rille
, just where it bends toward the west.
The model features a teardrop shaped fuel tank, open shaft drive, cantilever suspension, 21-inch front and 18-inch rear wheel, with Metzeler Rille