[madbadgalaxyman (Robert)]

Mr Boojum,
Sydney is not a good place for visual observing, so you will have to do what a lot of us do in order to get a clearer sky.......

Best is to pack that 'scope in the car and head a long way West (at least, best to head west, at most times of the year), as I well know from my many years of regular visual observing in the Sydney Region.

There is a strong rainshadow effect due to the North-South Ranges, so when you cross the ranges and reach the Western side of the tablelands, it is often much clearer than in Sydney.

Oberon/Sofala/Lithgow still get "mountain weather" which is cloud formed due to the effects of the mountains, but by the time you reach Bathurst, Orange, and further west, it is often a lot less cloudy than Sydney. Parkes, for example, is even less cloudy than Bathurst.

Better still, move to Brisbane, which is, on average, less cloudy than Sydney: by the time you reach Goondiwindi (inland from Brisbane), the average daytime cloudiness is only 2/8 !!

I often used to observe in State Forests near Orange (very dark and much less cloudy than sydney), though sometimes it would already be a clear sky immediately West of the ranges.
But if Orange was still a bit cloudy, I would head out to Parkes, and sometimes this did the trick....the Sky would be clear enough.

cheers,
mad galaxy man

Get out those topographic maps of the Western Slopes and Tablelands and find yourself:
a radio repeater station; or a state forest; a cleared hilltop or mountaintop ; or a farmer's property
(most farmers don't mind you observing on their property, as long as you first tell them what you will be doing at night; sometimes, $20 will also encourage the farmer to let you observe).
All these are good options for finding a rural observing site without obscuring trees.