If you haven't already, you should read Sagan's book. A curiosity appears on the last 2 pages which may belie his claim to have been an atheist. He describes the work of a sooper-computer calculating PI out to some 80 gazillion places in Base 11 and describes a raster which occurs way out there. He describes it as "The Signature Of The Maker."
Michael
The movie trivialized a number of important features of the book. Despite that I found it an interesting visual experience -- filling in from the book wherever it departed. Jodi Foster is one of two or three Hollywood females that can convincingly play a non-brain dead role. This, unfortunately, wasn't one of them. More the script than the acting.
Sagan was a non-believer, not an atheist. He was hostile to fairy tale religion (isn't everyone hostile to other people's fairy tale religions) but he was open to the idea of a creator.
Just my opinion.