Northern Arc
Explanation:
The terminator runs N-S, but many geologic structures dont. Because of this, as we observe an individual large feature we see different parts of it under varying illuminations. Paco Bellidos remarkable (shot with a 5 telescope!) image of the northern shore of Mare Imbrium is an example, with the Alpine Hills (right, and too small to be called mountains) being viewed under high sun, emphasizing their blocky nature. Note the hints of the rille in the Alpine Valley. Near the middle of this 800+ km long swath is Plato whose floor (with 4-5 visible pits) and rim are optimally shown. Further west (left), the rising sun reveals the lineated texture of ejecta from Sinus Iridum. And in the foreground is a collection of Imbrium basin inner ring fragments, strangely protruding through the mare while all the rest of the ring is missing.
—
Chuck Wood
Technical Details:
18 Feb 2005. Sky Watcher Maksutov 127mm + Celestron Ultima 2X barlow + Philips ToUcam Pro; mosaic of 5 images. This mosaic demonstrates that also with little telescopes you can make interesting shots (for me it's a bit astonishing to be able to record Plato's craterlets on a 5" telescope).
Related Links:
Rukl Sheets 2, 3, 4, 10, 11, 12
El Beso en la Luna