Sunday, September 14, 2014

September 14, 2014, 2:43 - 2:44 AM

The Moon was at an in-between phase last night, Waning gibbous on its way to Last quarter. I find the quarter (or "half") phases most interesting, as details tend to show up more sharply due to the long shadows at or near the terminator.

I'm presenting these photos out of order. This is a regular image taken at 2:44 AM. In it you can see the remarkable shadows in the craters along the terminator, as well as sunlight reflecting off the tops of mountains beyond the terminator!

However, the "bright" parts of the Moon, where the sun is closer to directly overhead, are washed out and overexposed. They show up better with a short exposure shot at 60 frames per second. As these shots are very dim, I needed to adjust the brightness and contrast. This also brings out fine details not visible in the normal photograph. (The colors in this photo are, I believe, a side effect of this adjustment.)

This also causes some of the fine details along the terminator to get lost. Here is a close-up of those details from the first photo:

A note on the sizes of things:

The large round feature along the terminator in the top half of the photo is Mare Serenetatis. There's a small bright crater at the bottom called Menalaus, 27 kilometers across - about 17 miles. That's not even the smallest feature in this image. Not bad for a picture of something 238,900 miles away!

Here Menalaus is the bright crater on the center left. The image clearly shows many smaller craters south of it. And check out the wrinkle of Dorsa Smirnov clearly visible in the upper part of Mare Serenitatis!

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