An example of wide field imaging: The Makarion chain, a realm of galaxies in Virgo . Exposure times were two hours using a blue filter combined with 40 minute exposures using red and green filters:
The next image is M31 the Andromeda galaxy using a 4 inch refractor . This image was taken using exposure times of sixty minutes for each RGB colour filter combined with a two hour exposure using a Lumicon H Alpha filter: