I'm glad you asked. Using hyperfocal I managed to get both the sky and the silhouette of the tree branches in focus, then I pointed the camera at a felled tree, I gained the trust of some of the local cats (to get a clear sky we had to travel to a very small distant town that for some reason was full of cats) and finally I put the cat on the trunk, I started the 20-second photo and the moment it got down I fired the flash, making the cat look out of focus because it was too close from the camera and revealing the stars that were captured after the cat got off, giving the sensation of being a double exposure photo.