Each image is made up of lots of different photos of the exact same spot of the night sky, taken with a long exposure time, which are then layered on top of each other to build the final image.
Pullen said: “I take the same photos again and again of the same patch of sky, night after night, week after week – sometimes month after month.
“For any individual photo, it can be several weeks to several months of time.”
Pullen hopes to inspire budding astrophotographers to give it a go, and will be giving a talk at the beginning of each exhibition of his work.
He said: “It’s an incredibly challenging hobby…but if you’ve got the patience, and if you’ve got the right techniques, it is actually possible.
“I hope I can show that you can take images of space from a city that can rival those from out in the countryside, or in the desert, or even on the top of a mountain.”
The exhibition is on selected dates until 7 March.