Ok I just read through this topic:
http://www.iceinspace.com.au/forum/s...ight=takahashi
and now suspect my question has been answered before, and the consensus formed that:
* unless one lives in dark skies, spend less by going for a big aperture non refractor, for now.
Unfortunately the counter-examples given: 10" dobsonian, etc, seem to be much less portable than a 4" refractor. With its sheer size it is going to stay in the backyard, not go to the country for a weekend in a travel case.
Lets look at a 10" newtonian, for example a Celestron C10 for $3000: the total weight is 42kg.. again, it isn't going to travel easily
What about an 8" SCT, example weight, 19kg of which 8.6kg is the tripod/mount. This seems sort of equivalent to a 4" Takahashi in terms of portability, but maybe the 4" refractor is still "ready to go" versus an 8" SCT.
So now I've got an issue: for urban skies a huge scope is better but my garden is not blessed with much sky view. To have one for camping or a weekender, I need something that is going to be somewhat portable.
4" refractor ? or is there something else for similar money, and more aperture, that is no less practical..