The Far Side of the Moon

1998 Feb 15

The first few months of 1998 frustrated California amateur astronomers with storm and rain, yet as I found myself leaving work in the small hours of 20 February, I noticed clear sky and an old Moon rising, between last quarter and new. Members of my observing group had mentioned that night's extremely favorable libration for observing the (Selenographic) west limb of Luna, so I hauled out my 63 mm Brandon refractor when I got home to Palo Alto.

My guilt at not setting up larger equipment evaporated with my first glance through the eyepiece. At 59x, the seeing was visibly poor -- the Moon's limb rippled and shook like a flag in the breeze. Even so, the substantial libration was obvious -- Grimaldi stood far in from the limb, dark and eye-catching in the high sun. Shadows were too short to show much topography, but several prominent albedo features aided navigation. The dark patch in Riccioli, as well as Lacus Aestatis and Cruger, all made it easy to find my way. Beyond the latter two, closer to the limb, lay a prominent rise with a dark patch beyond it -- a high point in Montes Cordillera, overlooking Lacus Autumnae. Crater Eichstadt, to the south, confirmed the identification. Beyond the Cordillera I found the lower Montes Rook, with perhaps a hint of Lacus Veris at their base, and still farther off, crossing the limb, lay a larger dark patch, well seen and unmistakable. It was Mare Orientale, the Eastern Sea, on the Moon's far side.

I picked up the Baby Brandon, an easy one-hand carry on its light photographic tripod and prepared to go inside and to bed. Then I caught myself laughing at the incongruous name of one of the features I had looked at. Lacus Autumnae means "Lake of Autumn", but Scorpius was climbing up the southeastern sky. It was almost spring.

Jay Reynolds Freeman; 1998 Feb 16