I love the idea - it's such an awesome concept.

Have you researched at all what constant sun would do to one side of a planet? I don't know, but it would interesting because I would imagine it to be a scorched wasteland, but I don't think it would be on fire - there wouldn't be anything to burn. I may be wrong.

I agree with Gidde on the sea. It's a bit too light in colour, I think, or too green or something.

Also, I think it looks great, but more labeling of physical features (seas, mountain ranges, etc.) would make it look more impressive.