APOD: 2020 August 24 Б Crescent Moon HDR
Explanation:
How come the crescent Moon doesn't look like this?
For one reason, because your eyes can't simultaneously
discern bright and dark regions like this.
Called
earthshine
or the da Vinci glow, the unlit part of a
crescent
Moon
is visible but usually hard to see because it is much dimmer than the sunlit arc.
In our digital age, however, the differences in brightness can be artificially reduced.
The featured
image is actually a digital composite of 15 short exposures of the bright crescent,
and 14 longer exposures of the dim remainder.
The origin of the
da Vinci glow, as explained by
Leonardo da Vinci
about 510 years ago, is sunlight reflected first by the
Earth to the Moon, and then back
from the
Moon to the Earth.
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
NASA Web Site Statements, Warnings,
and Disclaimers
NASA Official: Jay Norris.
Specific
rights apply.
A service of:
LHEA at
NASA /
GSFC
& Michigan Tech. U.
