Hi Sam,
1. Within Sydney, pretty much any dark park, oval or sports field is as good as another as the Sydney light pollution dome covers an enormous area.
I have tried an oval in Randwick (thanks to Mental) and also the Turramurra golf club carpark (see
http://nsas.org.au/observing/) which was surprisingly better than I expected.
2. For a Saturday night under the stars, Katoomba airfield is probably the best within easy reach, its an easy 1.5 hour drive and you will see the Milky Way.
3. There are other useful sites further afield - notably:
- Cathedral of Ferns camping ground at Mt Wilson,
- Mount Banks on Bells Line of Rd, use the carpark a few hundred metres off the main road.
- Hargraves Lookout and/or Mt Blackheath, on Shipley Plateau west of Blackheath. Hargraves has a cliff on 3 sides and awesome low horizons. Its also the darkest location this side of Jenolan Caves.
- Hassan's Walls, a high rocky ridge near Lithgow. To reach this drive into Lithgow along the Great Western Highway and turn right at the traffic lights into the main part of the old town, and watch for Hassans Walls Road leading up the hill.
- Lake Lyell, west of Lithgow (there's a camping area beside the lake)
- the showground at Rydal, west of Lithgow. The showground is on top of a hill, excellent horizons and dark.
The Katoomba and Blackheath sites are 2h from the city. Lithgow is 2.5h.
4. Lake St Clair, north of Singleton. This is a rather pleasant recreation area with a nice camp area beside a lake, dark if you get away from the people (many spots). About 3.5 hours drive from the CBD.
5. The ASNSW has a property at Wiruna, west of Ilford, halfway between Lithgow and Mudgee. It's about 3.5 hours from the CBD.
6. In good weather, Mt Kaputar offers the finest seeing in NSW with camping and cabins. The best observing area is a large clearing which is reached by walking 200m down the Barraba fire trail, then pushing to the left through a thin wall of scrub to a dead flat lava field the size of a footy oval. Vehicle access can be arranged with the ranger.
In comparison with the Warrumbungles, Kaputar was considered and a site survey done for the AAO, however it is further north and closer to the coast so it cops cloud pushed inland from coastal lows and cyclones off southern Queensland, with the result that it has fewer cloud-free nights than Siding Spring. But if it is clear it can be awesome.
7. Another excellent site similar to Kaputar is Mount Buffalo, in northeast Victoria. There is an excellent camping ground on the top at Lake Catani (you will need to book) and many things to do during the daytime - important if you have family with you - as the area around Bright is full of holiday attractions starting with wineries, fine food, trout fishing, cycling, river kayaking, swimming and much more. The best part is that there are dozens of perfect telescope sites on the mountain top, or you can even set up your scope in the camping ground beside the lake if you don't mind the occasional onlooker.
The drive to Mt Buffalo takes 8h on excellent tar roads all the way, about the same driving time as to Kaputar.
8. If you're prepared to go 6 hours drive, that puts you in the Snowy Mountains where there are plenty of camps sites, picnic areas around the northern end of the national park that should give quite spectacular night skies.
http://www.environment.nsw.gov.au/na....aspx?id=N0018