The phase of the moon doesn't have much obvious effect on the shape of the corona except when the drops are large and the corona is small.
Because it is so close to the moon the innermost ring in the lower right image hugs the shape of the first quarter moon.
Almost a week later and the moon is full.
The drops are quite large again so the corona is relatively small.
They are also a more even size because a second ring is visible in the longer exposure.
Canon EOS 20D 21st and 27th April 2010