I'm fairly certain this is a Spotted Orb Weaver ( Neoscona crucifera ) spider. Its coloration and markings are truly striking! I was thrilled I was able to capture so much of the web in such a low light shot.
This beautiful little spider has been hanging out on our back deck since February. It is nocturnal and sleeps in a tight ball in the corner of a support beam during the day, so it's been very difficult to get any good photos of it. This was one of the better images I managed to capture thus far.
I have a larger version available, if anyone thinks this would make a good print.