I like the idea of a one magnitude jump as being a good rule of thumb, even though I did not follow that advice when I bought my second scope. Primarily because I cured aperture fever.
I have not defeated the idea larger aperture shows more, that would be something and I don't imagine making many friends pursuing that angle. I just changed the way I think about it by putting emphasis on myself to see more through whatever aperture I use currently. It's challenging, to be sure, but I obtain personal reward in the challenge itself. Almost ironically, that's (almost) true even if I do not see anything at all. NGC 660 has so far avoided me, but I am still determined to go after it. Even just a peek at it is more rewarding in it's own right than nothing at all. The thrill of the chase. The employment of not just machine, but of man and machine. A 12" offers the same challenges, only those challenges are deeper.
Absolutely fine to observe through larger aperture, there is plenty of cosmic beauty to be had. That's what we're after. I chased aperture nearly all my life looking for every more detail. Until I made the paradigm shift from the equipment to myself as an observer. I do not get the beautiful images of a larger aperture, but I feel the same reward with what I have learned to see in a smaller one. Again, it's fine to go big because those same challenges exist on a deeper scale. But, the point is, the emphasis on observing and the reward that comes with it almost makes our equipment meaningless. Beauty is simply a matter of observing and the cosmic scale we feel rewarded by observing it. That doesn't change the fact larger aperture shows more, but the "fever" itself is tamed.
Sigh, I digress and talk too much...get the largest aperture you can afford and use easily enough, I say the 12" (over twice the surface area) is a nice almost 1 magnitude boost over the 8". Most importantly, get it for the right reasons and enjoy whatever aperture you decide on. There are cosmic challenges to be had in every aperture.
Edited by Asbytec, 25 January 2019 - 09:09 PM.