Saturday, September 18, 2010

InOMN - 18 Septembre 2010

It's INTERNATIONAL OBSERVE the MOON NIGHT. If you've waited past Civil Twilight, the ancient angular momentum in Earth's rotation is catching up once again with our Moon. Waxing Gibbous, it appears much like it did 886 days ago, when Jocelyn Sérot captured this image. If it's been a while since you looked up, really looked up, AT the Moon, you may need to be reminded of some basic facts. If so, don't feel bad. Everyone tends to ignore beauty in their own backyard, and the Moon is patient. No one is poor who has such adornment framed by an apartment window, a wide meadow or a skyline, a soup line or a battlefield [LPOD/ILUJ/Jocelyn Sérot].

It's not Full, and there's no eclipse. What can you actually "observe" on the Moon, tonight?

Like Galileo, you can surprise yourself. Even modest magnification will delight the eye and allow a better view of the Moon's depth of field. You may need to remind yourself of the Moon's true distance. From limb to limb, it's diameter is equal to the distance from New York City to Las Vegas, for example, and it's almost thirty Earth-diameters away (a lot further than it looks).

Take a look at the richer field below, taken from within the mosaic above, specifically at the southwestern side, near the terminator. It's early morning on the Moon there, and because the shadows are long, some very subtle features that are ordinarily invisible at this distance (and sometimes harder to see up close) come into view now, and again briefly two weeks from now at local evening, when, unfortunately for most, the Moon will rise in the wee hours before dawn.

Like the Moon itself, there's more to the full-globe mosaic by Jocelyn Sérot than immediately meets the eye. The original combination of hundreds of exposures resulted in a detailed "observation," better than the best photographs taken through large telescopes just a few decades ago. Forget the easy stuff, the gestalt of huge mountains and rays for a moment and look again at the close-up, immediately above.

At dead center is a "ghost crater," where a ring of worn mountains are all that remain of a once-proud and craggy crater long ago overrun with molten material. Immediately to it's west is one of the Moon's many low-lying "domes."

Dome Kies Pi presents a very smooth low profile above the mare plain. It's best seen right now, while early morning shadows are long.

Need a better look? Thanks to the WAC Preview program written by Ron Evans, an outstanding contributor to Charles A. Wood's Lunar Picture of the Day forum, there are no better views available than this LROC Wide Angle Camera image. (Oh, I should remind you that LRO is "up there," too, by the way. By tomorrow afternoon, it will have orbited the Moon 5,700 times.)

That ghost crater is easy enough to cross-reference with the smaller-scale pictures, further up. But we're almost too close to really "see" this dome, looking through the LRO camera. The gentle rise of the dome, visible even in low power telescopes if you know where and when to look, is probably best "appreciated" from an aesthetics view, moving out into the backyard and tracing out the landmarks in finding it on the very face of the Moon [NASA/GSFC/Arizona State University].

Here's a look downward again only an orbit later, when LRO traveled a little more directly overhead. More accurately put, the Moon continued rotating under the LRO's polar orbit, allowing the spacecraft a complete data-picture of the Moon over time.

A little later that same month, here's the same area in late afternoon illumination. Can you spot Dome Kies Pi?

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