Apogee Moon, Perigee Moon
Credit & Copyright:
António Cidadão
Why don't these pieces fit?
This third quarter Moon (left) and first quarter Moon were
both photographed during the last lunar cycle or
lunation with the
same telescope and camera.
But, simply combining the pictures into one sharp, full
surface view
would clearly be a problem.
In fact, on October 6th the Moon's third quarter phase
happened to occur near
lunar
apogee, the farthest point in the Moon's
orbit.
On September 21st, the first quarter phase fell close to
lunar
perigee, the Moon's closest approach to planet Earth.
Viewed two weeks apart,
the resulting difference in apparent sizes would not be
noticed by casual skygazers, but the
simultaneous side by side comparison makes it hard to ignore.
Skygazers will likely
notice the Moon
next week though,
as it slides through Earth's shadow during October 27th's
total lunar eclipse.