May 28, 2011

Changing Color

images by Tamás Ábrahám, Zsámbék, Hungary

Continuing our considerations of the colorfastness of the Moon, note how its brightness and hue change
as it rises. This effect, of course, is due to absorption of light by the atmosphere, which is densest at the
horizon because of the long path length, and thins and has less effect as the Moon rises higher in the sky.
And in Tamás' images, clouds, not just the transparent atmosphere, also degrade the Moon's brightness
and color. As shown yesterday, the color of surfaces varies depending on the actual nature of a surface,
observing conditions and data processing. Astronomers have long known this and are very careful to
standardize observing conditions and analysis to achieve accurate and consistent results. As amateurs
we can be more free to depict the Moon and the rest of the universe accurately or not. Tamás' images
are probably quite accurate renditions of the changing appearance of the Moon, but not the actual color
and brightness of the Moon. And that is OK.

Chuck Wood

Technical Details
05.18.2011, 20:04 - 20:22 (UT). 8" newtonian reflector (F/5) + Canon EOS 400D camera. The photos
were taken from Tamás' backyard.

Related Links
Tamás' website

Yesterday's LPOD: From Lavas To Wagtails

Tomorrow's LPOD: A Wetter Moon

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