Astro-Drawings 2003

by Gerhard Niklasch

The Moon

Rima Agatharchides

R. Agatharchides

During some minutes of exceptionally steady seeing (at 200×, I had for the first time been able to see three of the craterlets in Plato as little bowls!), I was following Rimæ Hippalus from Campanus A to the North when I noticed Rima Agatharchides - much narrower than the main strand of R.Hippalus, and running at a funny angle through the ill-defined broken-walled plain known as Agatharchides P (on the left of Rükl chart 53). The really striking thing about this corner though, aside from the tiny cleft in the U-shaped ridge surrounding the N end of R.Ag., were the half dozen or so miniature craterlets just W of its northern half. Rükl hints at just one of them, and even Harold Hill's drawing of Rimæ Hippalus in his famous Portfolio of Lunar Drawings omits them.

The ragged shadows of the eastern rim of Ag.P added their own note to the scene, with one tip just touching the Rima; and so did the chain of barely illuminated peaks trailing off beyond the Terminator on the West (to the right here).

The area shown is rather small - about 60km wide E-W, but easily located starting from Bullialdus. What is drawn as a fine round 12km crater at bottom right is probably less round in reality but this is how it presented itself to the sketcher's eye interested merely in context at this point.

Drawn 2003 June 09, c.23:15 MEST (21:15 UT), JD2452800.385
Moon age: 9.7 days, sunrise longitude 328°58', subsolar latitude +31'
Libration: long.-4°42', lat.-4°30', limb angle 136°16', tilt 6°.507

Instrument: 8" f/5 Newton; Nagler Zoom at 6/5/4mm (167× - 200× - 250×)

G. Niklasch / Wed, 11 Jun 2003 23:42:42 MEST