[poider (Peter)]

G'day, I have seen a few articles about the inabilities of Dobsonians for astrophotography, but I have seen plenty of newtonians advertised for astrophotography, I was under the impression that 'dobsonian' is just the mount and that a newtonian on a lazy susan is a dobsonian, and that a newtonian on a azi or eq mount is a newtonian.
If the same tube can be called different things depending on the type of mount then why is the dobsonian so hard for astrophotography and not the newtonian?
Peter