Being artist and scientist at the same time
There are many people in academia with hobbies. Some very famous scientists like Heisenberg and Weyl are prime examples. I know a professor who paints for a hobby and keeps pictures of his paintings somewhere on the personal web page. It's tough to juggle work and hobbies, but you are already doing that. 

However, you are now under a contract from the publisher. Will you have time to do your research? If I were you, I'd take a vacation from my research job, and focus on the contract work. If it takes you many more hours than your hobby took, you need to make a choice. Or you'll end up burnt out.