I have created these images by downloading red and blue images from the Palomar Deep Sky Survey. I then created a green component, before combining to create a full colour image.
In one or two images I have superimposed components from my own images to fill in parts that have been overexposed on the Palomar shots.
For example in M13, my stars fill in the centre of the cluster, and M42 which fills the centre of the nebula which was completely overexposed on the Palomar shots.
Unfortunately the online Palomar Survey only allows you to download up to one degree of sky at a time, so the field of view is quite limiting.
Luckily I was also able to scan in plates directly from the Palomar Sky Survey and Southern Sky Survey as Northampton Astronomical Society has a copy of these plates.
From these plates I was able to produce some very wide field views using these images.
This is an ongoing project and new images are being added all the time, so keep looking in.