Thanks Alan and Carol. Regarding capture ......
...... The kit I use is here
The camera is an astro cooled CCD camera capable of cooling to 27 degrees below the ambient temperature. This helps combat noise as each exposure is 25 minutes long. I am able to do that as the smallest scope and gold camera is setup for guiding, so it locks onto a star and will keep that star in the same position all night. Connected through to the mount, that means I can get these long exposures.
The camera is a mono one and the way to get colours is to take images using different colour filters then merge them at the processing stage.
If anyone is still awake
.... This image is taken using narrow band filters, which only pick up a small bandwidth of certain lights. A number of 25 minute exposures were taken with each filter, for example 19 for one of them, and then they get stacked together in order to effectively boost the signal.
In total, this is a combination of 48 x 25 minute exposures.
Happy to answer any other questions, it's very technical and probably boring to most, and I am also very much an amateur