Certainly, you should cover the camera inlet when making darks. Besides that - using smart ATIK-383L+, - in the software menu where you makes darks, you suggested to find options, what kind of pictures want to make? These are 1. light, 2. dark, 3. Flat, 4. BIAS. When making these kind of frames, you have to select the appropriate mode, because i.e. in our case, the camera so smart, that will "cover itself", means you can leave your telescope uncovered, the camera will help you, will do it inside too. Give a try! But as a rule, everyone is rcommended to cover the tube, when making darks.