Moon weirdness - the south polar sequence

by Jane Houston Jones


It was windy and cold and late when we returned home from a day-long kayaking trip to a nearby river yesterday, but lunatics just can't say no to a good-looking moon view. We four moon lovers were almost too tired (and bruised in my case) to lift out even one small 6 inch F/5 reflector for some mooning.

But reason prevailed. One small scope was set up and we took some turns looking at the moon, and rushing in to keep warm. The area of the moon that caught my attention last night was the area from Clavius to the South Pole.

Out came RUKL (page 72 and 73 to start with) and the hunt was on. The floor of Clavius was lightly bathed in sunlight. On the floor of the great walled plain, the string of craterlets were prominent. I also noticed a snaky "U" shaped line - a shadow-like rille on the southern sloped side of the crescent of craterlets. This snaked around from the craterlets near Porter and around the bend back towards the crater Rutherford on the southern side of Clavius. I haven't noticed this shadow before.

Moving on towards the south pole, and onto RUKL 73 were the trio of featires, Gruemberger/Cysatus and the craters Moretus and Moretus E. All were brilliantly shadowed with deep crescents of darkness. The central peaks on Cysatus and on Moretus were jagged and black. But this is all normal stuff. It started to get weird a little south of here.

My hands were cramping up from rowing oars all day, and I didn't much feel like sketching. But we drew straws, and since we were at my house and I had the sketching material, I sucked it up and set up a chair, flashlight and sketch kit.

It looked like there was a new crumbled walled crater -- which we dubbed the south polar sequence -- between Moretus and the limb. Right up against the wall of Crater Short was what appeared to be a crumbling wall of a huge crater. Open your RUKL to chart RUKL 73 to follow along with me. I made a sketch of this area from Clavius to the terminator, but have not scanned it yet. For a great photo of what we observed, also open the Hatfield Photographic Lunar Atlas to Plate 14A and better yet to Plate 14d. 14d shows a similar libration better. South of Moretus was a dark vertical shadow, which I now know was the rims of the row of craters south of Short and Short B and A, and some crater walls from unknown (to me) craters. The weird new wall was made partially by the terminator and partly by the favorable libration last night. The vertical shadow formed the base of a rising sun lit wall nearly the length of Clavius! On the rim of the "wall" were features which turned out to be the crater rims of Newton and Short. Hatfield doesn't identify the features as they are bathed in shadow on the photographs.

Outside the "rim" of our "south polar sequence" was another shock ring appearing feature - made of the walls of Demonax, Schomberger, Simpelius -- three craters which appear elongated and oval-shaped from our view, round and fat on the RUKL libration chart V. All three are on the same angle. Could they share a slope of a long gone south polar crater, now crumbled into oblivion except for the upswelling landscape? Probably not, but it was nice to think about it and to talk about it. It was too cold and nearly midnight, so I took a last look around some unfamiliar and familiar features. I looked at Crater Faraday - named for english chemist and physicist Michael Faraday, who is buried in Westminster Cathedral in London. I saw flowers on his burial place once - placed there by a graduating class of chemistry students at a London University. I'm glad he has a crater named after him! Faraday was snug up against crater Stofler. These two make another interesting companion-sharing space separated from Maurolycus. It was time to call it a night. It had been just another day in the life on the moon.

Equipment: 6 inch F/5 "Red Dwarf" reflector at 125x through a Vixen 6mm Lanthanum.