first ever moon shot

well i was out last night dodging the clouds trying for M13, as soon as i got outside and set up i noticed the moon setting in the west so i swung over and made this image, how can i control image size on the sensor?, this was made with my ED120 and a Canon 5D but since i don't have choice of eye piece when imaging as far as i can see my options are just switch to a crop sensor camera body or use a barlow in between the Camera and scope?

Neil.