placement of aircon outdoor unit

[Rob]

Hi, I have a permanent setup in my small backyard, with an ED120 on a pegasus pier concreted in. No dome, just a weatherproof cover. We're thinking about getting a new r/c ducted aircon, and the outdoor unit might have to go in the backyard. Have others experienced air distortion due to an a/c outdoor unit? The unit will probably be about 6m away from the telescope. We live in Canberra so the aircon will probably be running regularly on winter nights to keep the non-astronomers warm inside.

[glend]

I have no comment on placement of the unit, but a couple on the cost of ducted systems. I had a ducted system in my two story house in Sydney, and like most big systems it was a three-phase system, meaning it required three-separate phases of AC from the power grid. This is an expensive thing to install, meter, and run.
In contrast my electrical engineer son, installed five split systems in his two story house in Brisbane, his initial outlay was about the same as the ducted system he had quotes for, but they run on single phase AC, and there is no need for zone splitting like with ducted systems, not expensive duct work. His split systems are only used when needed, with very small systems in bedrooms, and a large unit in the main living area. Split System outside units can be rack mounted off walls, another advantage. Of course having the outside unit near the rooms they are cooling or heating, is a good idea.
Some spouses may hit split system with an ugly stick, but they are considerably cheaper over the years, and fairly easily replaced.