Rob,
It's a long way to come to do astrophotography. If this is the main goal of your trip, you really need to base your choice on a combination of finding the very best weather and the most interesting part of the sky first, travel destinations second, star parties last.
For someone from the northern hemisphere our southern winter sky is probably the section of sky you'd most want to see and photograph. During May-September, the north center - north west of the continent is clearest 80+% POPS (percent of possible sunshine) - night skies follow this pattern.
See
http://www.bom.gov.au/climate/averages/maps.shtml
and in particular average cloud maps : -
http://www.bom.gov.au/jsp/ncc/climat...loud/index.jsp
These show cloud in octas for daytime 9am and 3pm. It makes it pretty obvious.
Avoid the east of the continent and definitely the south east where we all live which has moderately bad weather in winter. Just read all the posts here with people whining about the weather. That includes SE Qld where Astrofest is held and central east NSW where the South Pacific Star Party and IIS Astrocamp are held.
The star parties are all within easy travel distance of where the biggest populations are - in the south east in driving range of Brisbane Sydney or Melbourne. The population is biggest in the south east because that's where you find the biggest water supply from rainfall (read cloud) to support those populations.
Presumably you are only coming for a limited time and want to see many nights of completely clear sky. So you should go to the north west of Australia, avoid the south east and DEFINITELY not Tasmania where they have 5-6 octas of cloud on average in the winter. Go there for a holiday but leave the telescope behind. The guy who recommended Tasmania really gave you a bum steer. Worst weather in the continent.
For those of us that live here, we have many opportunities to catch clear skies in the generally cloudy south east and the star parties are great social events but by no means guaranteed clear skies. If you are traveling all the way here and for a limited time around the dark of the moon, I suggest you come here between June and Sept and look at places in areas like : -
- South of Darwin (Katherine)
- Kimberley Ranges
- Broome
These places all have great travel value as well as really clear skies. Of course, there are many other places - we're talking the north west quarter of the continent 1500km x 2000km of the country.
Keep your arrangements fluid and follow the best weather when you get here. No need to book & lock yourself down in advance.
cheers
Joe