by TheOtherBruce » Mon Jul 22, 2019 3:20 am
RocketRon wrote: ↑Sun Jul 21, 2019 5:57 am
I'm still mystified that with no atmosphere, the sky should be ablaze with stars, even in the daytime ?
Keep in mind that with no atmosphere, the sunlight is much brighter than you could find anywhere on earth. How much brighter? On the wikipedia page for the Moon, it's mentioned that the albedo (a measure of how much light is reflected from the surface) is about the same as road tar. And yet the lunar surface seen close up is, on average, a sort of medium grey. Look at it from Earth, and it seems almost white.
The sunlight's bright enough to wash out the dark dust and rocks. Sunlight reflected from the surrounding lunarscape is bright enough to illuminate the shadowed side of the astronauts and the LM. Look at the sunlit sides, and they're so bright all the colours are distorted. You can set the camera exposure for that, or you can set it to catch the much fainter stars.
I know the Apollo cameras were excellent quality (Hasselblads, I've got one) but at least back in the 60s they couldn't handle that sort of brightness range. It might be different now if you stuck the right kind of CCD back with the right programming onto a Hasselblad.
[quote=RocketRon post_id=293875 time=1563688647]
I'm still mystified that with no atmosphere, the sky should be ablaze with stars, even in the daytime ?
[/quote]
Keep in mind that with no atmosphere, the sunlight is much brighter than you could find anywhere on earth. How much brighter? On the wikipedia page for the Moon, it's mentioned that the albedo (a measure of how much light is reflected from the surface) is about the same as road tar. And yet the lunar surface seen close up is, on average, a sort of medium grey. Look at it from Earth, and it seems almost white.
The sunlight's bright enough to wash out the dark dust and rocks. Sunlight reflected from the surrounding lunarscape is bright enough to illuminate the shadowed side of the astronauts and the LM. Look at the sunlit sides, and they're so bright all the colours are distorted. You can set the camera exposure for that, or you can set it to catch the much fainter stars.
I know the Apollo cameras were excellent quality (Hasselblads, I've got one) but at least back in the 60s they couldn't handle that sort of brightness range. It might be different now if you stuck the right kind of CCD back with the right programming onto a Hasselblad.