Hitchhiker's Guide to Rukl Chart 7

Belkovich (David North <d _at_ timocharis.com>)

Okay, so it's the full moon and you're supposed to do ray tracing, huh? Notable ray craters abound... and if you look close, you can see the dark halos around such craters as Tycho, Copernicus, Kepler... just about any crater named for an early astronomer.

Heck with that, sez I.

The real trick is to work the limbs at full moon. There is always a terminator, and when you get a terminator combined with a favorable libration, you can see things that are simply not available at other times. Edge-on craters are a good example, particularly near the poles, where you can get a good view of terracing from almost ground level.

But tonight, I got a different kind of surprise: the terminator included Belkovich, a large walled plain next to the Humboldt Sea. Though it doesn't show hardly at all in the book, instead of a central peak, it has a range of mountains in the middle that includes at least four major peaks. It's unclear (from looking) how this formed. It looks suspiciously as if the mountains might be the result of a secondary impact, but that's not convincing. Whatever the cause, they form an excellent sawtooth ridge, sort of like the best Rocky Mountain hog backs.

I don't know how often this shows up, but I think it probably a rare thing. All the more reason to remember to make at least a brief hunt of the limb terminator at full: the old saw that the full moon is not worth looking it could not be more wrong. It is in fact the best time to see things that are otherwise never available to us.

See also chart 6.

Endymion (JRF <freeman _at_ netcom.com>)

This prominent, dark-floored crater is a "landmark" feature, easily recognized and useful for orientation. Just after sunrise, its eastern wall casts a particularly broad shadow across the crater floor.

Endymion (David North <d _at_ timocharis.com>)

When near the terminator, Endymion can look very odd (as opposed to its normal flat, dark spot) almost like a grand walled plain in such low angled light.

Linea Mercurius (Bill Arnett)

UT 5/20/00 0949: Tonight I found two parallel linear features near Mercurius (near Endymion). Neither are marked in Rukl so I dubbed them Linea Mercurius :-) I suppose they're not real, just ridges with the light just right but they were very prominent tonight and caught my eye immediately.