I created that piece when 3D software was pretty much still in its infancy. I've tried a few, but I'll bet it was Blender (since I've stuck with it to this day) with a little post work in Photoshop.
I do have an online portfolio and, judging by the email I received, you already found it.
Astronomer wrote:The look of this is really unique. I'd be interested in knowing what tools you used to draw this. And I'd love to see more of your work. Do you have a portfolio or DeviantArt page you can link to?