[RightWhale]

12-1/2" diameter is getting up into the professional range of telescope sizes. Or a serious amateur in a good location with appropriate viewing conditions. The photographer has put a fair amount of time into his set-up, and possibly some money as well, although money can be replaced with labor to a degree.

[petuniasevan]

That's true. I could go out and buy a Dobsonian "light bucket" relatively cheap, but it's useless for astrophotography.
As for a well-built, quality 12.5 inch Newtonian, it's just too big, heavy and ungainly for many people.
A Schmidt-Cassegrain or Matsukov will do beautifully, but we're talking some serious bucks here.
But hey! Got too much time and money? Here's a new wallet-slimming hobby!
Wish I could afford to do that, though...