Explanation:
Venus goes through phases.
Just like our Moon,
Venus
can appear as full as a disk or as a
thin as a crescent.
Venus, frequently the brightest object in the post-sunset or pre-sunrise sky,
appears so small, however, that it usually requires
binoculars or a
small telescope to clearly see its current phase.
The above time-lapse sequence, however, was taken over the
course of many months and shows not only how Venus changes phase
but how it's apparent
angular size also changes.
In the middle negative image, Venus is in a new phase, the same phase that occurred during its
rare partial eclipse of the Sun in 2004.
