Here is a quick tip that I knew but didn’t realise until I faced a problem when shooting a cityscape at night. Every photo I took I noticed strange lights and glow in the final image that was taken. I gave the UV filter a nice clean with the cleaning cloth but still no luck. After a few minutes I realised that it may be internal reflections caused by the UV filter due to the long exposure and all the lights in the shot.
I took the filter off the lens and bingo!! The photos were clean as a whistle. Check out the before and after and remember to take the UV filter off the lens when shooting at night, especially a scene that has many different lights and requires long exposures.