Best seeing areas in Australia?

[gregbradley]

I am wondering what areas of Australia have the best seeing? What's you experience?

Also what areas of NSW have the best seeing?

Greg.

[Kevnool]

I,m thinking Greg anywhere away from the coast (Water Vapour) on the western side of the ranges and inbetween them little villages that are scattered out here.

Cheers Kev.

[gregbradley]

I have noticed west of the ranges seems better for sure. I guess there is very little mountainous terrain in Australia west of the coastal ranges in the Eastern half of the country. That's where my dark site is. Seeing in the winter can be very good. In summer it can be very good but less often.

I guess the problem with Australia is it the lack of high mountains. I wonder what our the Snowy Mountains would be like?

I remember one time stopping on the side of the road of Mt Selwyn in NSW and the sky was particularly spectacular.

What about Broken Hill - is that good?

Greg.

[Paul Haese]

Kev, that is not entirely right. Water vapour is less of a problem for seeing. It is mainly the laminaire flow which is important for seeing. Water vapour can create clouds and that does disturb seeing, but it is less important than mountain ranges and terrain issues.

So Far Anthony and I have found a couple of sites. First and foremost is Exmouth WA. Highest level of seeing experienced by either of us yet, not been there myself but I have seen the video. We think though that Broome could be better yet. One of us was going to go there this year, but it cannot happen now. Next eyar perhaps.

Next, Clayton Bay SA. I have had DIM (seeing meter) results from there with long periods of 0.7" and an average of 1" seeing. I have done a few planetary imaging tests from there (see here (http://paulhaese.net/Mars29December%202009.html)) but yet to try in earnest. For DSO imaging though it has been a great spot. 1" seeing generally and the results have been quite sharp I think. Dark sky town too. Perhaps we all ought to setup there. Plenty of land for sale. Clouds can a problem though.

Murrembateman is also good too. Anthony's images from his home very good and he has a good record of the seeing conditions there. Perhaps contact him and ask his opinion.

Seeing at Broken Hill is also good. Trevor Barry's images attest to that. The problem though is that seeing can be inconsitent. I am sure Trevor will be able to tell you more about that. Heat during summer could well be an issue too.

Arkaroola has potential too. Seeing in winter can be sub arc but summer it is crap. The heat plumes are a nightmare from what I have seen and heard. Been up there in summer and the seeing was quite bad.

I suspect that in the far north the seeing would be quite good too. There is little jet stream influence and Cairns are would have quite laminair flow most of the time. When I lived there I noted sea breezes dominate the air flow. Although cloud becomes a significant problem for this region.

Flow straight off the ocean though is what you generally need. If the flow dominates like that then you are onto something. You cannot have any intervening mountain structures as this kills seeing by virtue of eddies forming.

[gregbradley]

Good writeup Paul.

Coonobarabran in NSW is where there are some professional scopes. Looking at the images Louie and Ross and Marco have posted it seems the seeing there is better than most locations. I wonder if there is something more quantifiable on that point.

Greg.

[Paul Haese]

Well the only way around it is to do some DIM testing there. That could tell you what the seeing is at that point. Our society has an instrument office who could tell you more about how this is done. His contact details are located on the ASSA site.

[Rob_K]

I've got lots of experience in the worst places for seeing, if you'd like to tackle it by elimination. Mountainous areas are bad, unless you can punch through to the tops of isolated high peaks (a la Mauna Kea). Prevailing winds are broken up and funneled, there is altitudinal flow of cool air down the valleys at night, and differential heating of mountainsides causes a barrel flow (thermals, used by paragliders etc). Mix that up and you get chronic poor seeing. I occasionally go to flatter areas to observe like Snake Valley - people there might say, "oh, the seeing is off tonight", but for me it always seems brilliant compared to my mountain valley location. :lol:

Your mention of the Snowy Mountains is interesting though Greg because there are fairly extensive areas of high plateau. I've often wondered myself what it might be like in places there (apart from very cold!). Less air to see through (and therefore less air available to be disturbed) sounds good, but I suppose it would come down to whether the constricted air flow over the top has time to 'settle down' into an even flow. :shrug: Be very interested to hear from members who have observed there.

Cheers -

[gary]

Hi Greg,

The median seeing, as measured by the external DIMM (Differential Image Motion
Monitor) the AAT, is around 1.5". So by international standards, it isn't in the same
league as say, Manua Kea, with median seeing of around 0.43".

The site selection for the AAT was done after testing of various candidate sites
around Australia and this is detailed to some extent in a book I read on the construction
of the AAT a few years back but would need to find the reference again for you.

[Edit: "The creation of the Anglo-Australian Observatory" pp 48-59.
There as a copy years ago in Chatswood Public Library. Google books
have part of it available online here -
http://books.google.com.au/books?id=0iNd-JqR8tUC&printsec=frontcover&dq=Anglo-australian+observatory&hl=en&ei=qRdsTqbMJsbjmAXoutSSBw&sa=X&oi=book_result&ct=result&resnum=4&ved=0CD8Q6AEwAw#v=onepage&q&f=false
I recollect another paper published on the site selection as well, which I use to have a copy of, but which I would now need to search for]

They considered places such as Mount Woodroffe in the Musgrave Ranges,
which is the highest peak in South Australia, but eliminated it because
it was considered too remote.

They considered Mount Singleton in WA, which is about 250km inland south-east of
Geraldton, but eliminated it after much testing.

Mt Serle in the Flinders looked promising, but in the end Sidings Springs
was chosen as a compromise as it was already developed and it was close to
a major service center.

As Paul has noted and has been well documented in images by Anthony Wesley,
the seeing at Exmouth can be excellent but, anecdotally, as a site it is very
inconsistent because of the strong prevailing winds there at times where wind buffeting
makes observing impossible.

Mount Kaputar would probably have seeing similar to Sidings Springs if
not possibly better and also has the amenity of dark skies. Probably the best
site I have observed from within NSW.

Unfortunately no new large professional optical telescopes will ever be built in
Australia because of the lack of high terrain and good seeing compared to places
such as Hawaii, Chile, Antarctica, and the Canary Islands.

[RobF]

Good thread Greg
Paul, how do you do DIM testing? (or for that matter would be interested to hear from anyone that regularly quantifies their seeing - how do you do it?)

[strongmanmike]

That's not that far from Conna is it..? What amenity do they have ie power and accommodation etc at altitude, do you know?

Mike

[gary]

Hi Mike,

It's not far from the township of Narrabri which itself is 1.5 hours drive away from Coona.
There are camping areas at the top with full amenities but the NPWS has available
some wonderful cabins that have kitchens, a fridge, a stove-top, a microwave,
toaster, crockery, pots, pans, a jug, hot showers, multiple beds, fire places and that are
very reasonably priced and when shared with some friends, an absolute bargain.
They are situated at the top of the mountain (1510m). There is power at the cabins
but not at the observing site.

See http://www.environment.nsw.gov.au/nationalparks/parkAccommodation.aspx?id=N0038

Because there are a lot of trees at the top, there are no good places that are
normally readily accessible to setting up the scope. However, the NPWS has their
office in Narrabri and if you call beforehand, they may be kind enough to loan
you the key to the gated area they use for helicopter landings. We have observed
from there and it is only a few minutes back to the cabins.

There is a second area that is suitable to observe from and which is not gated
but it is not practical for carrying large Dobs to. For more portable rigs if you
don't mind carrying the gear a couple of hundred meters, then this alternative
site is ideal.

The road to the top has improved dramatically over the years but it is narrow
and one has to exercise great care, remaining vigilant for on-coming traffic
around blind corners.

Remarkably, given its location in the north-west of the state, it snows up there
and you will see a lot of snow gums. A stark contrast to the plains below.

The views are to die for and you can see across to the Warrumbungles
and surrounding plains.

[RCOS1]

This may be of interest:
http://www.northerngalactic.com/ArkaroolaFlindersRanges.pdf

But be aware that Australian weather patterns have totally thrown this information out. I know personally that Siding Springs weather has been impacted serverly over the past few years and looks to continue permanently.

[Paul Haese]

Rob DIMM tests are well described in the paper presented by Bert. Basically a DIMM takes readings through a telescope (in our case it was a 10" SCT), these readings are placed through software which makes an assessment to how steady the seeing is at any one point in time. Our societies instrument officer came and measured Clayton because the society is looking for a site of our 36" project. Searching sites all over SA will give us an idea of where to place the scope in the end and it helped to quantify our seeing.

Kaputah was used several times for viewing camps in the mid to late 80's too Gary. Did you ever go to these camps?

[ausastronomer]

Hi Greg,

Coonabarabran typically ( at normal township altitude) has fairly poor seeing by comparison to some of the better locations in NSW and Australia. I am not sure what it is like up the mountain where the AAO is located, I haven't observed up there. We regularly host groups of US observers to Coonababran and rarely do we experience nights of good seeing. I have observed many many times from both Timor Cottages and Warrumbungles Mountain Motel and you can count on one hand the number of nights of good seeing we have experienced. It is a rare night I can push past 200X on the planets in either the 14" or 18" scopes.

I don't think being near the sea has much to do with it. I quite often get exceptional seeing from my backyard at Killarney Vale which is 50 metres from the Southern side of Tuggerah Lakes and about 2km from the beach. I observe the ecliptic to the north across the lake which is about 20km long and usually get exceptional seeing as the temperature of large bodies of water usually does not change much in short time periods, unlike land masses. It is common for me to push 300X to 500X on the moon and planets and a few nights per year I can get well over that. The best I have done is 1050X on the Moon and Saturn on a couple of occasions in the 18" Obsession.

Mount Kaputah which is situated just out of Narrabri, about 90 mins North West of Coonababran, is renowned for exceptional seeing. It is probably one of the single best observing locations on the planet for excellent seeing combined with excellent transparency and very dark skies.

Cheers,
John B

[renormalised]

Hey John, what size was Armstrong's boot he wore on the Moon??:):P:P

Speaking of good skies....McKinley, south of Cloncurry, isn't too bad. Just go a few K's past the town (which is postage stamp small) and the skies are good. Can get cloudy during Summer (as per usual for up here), but now is quite good. Winter is brilliant. Gets cold of a night. My eyes aren't as good as they used to be but I can still manage to see 10 of the Pleaides on good nights out there. It's just a pity it's so remote because there are some cracker flat tops out there and good hills of the normal type as well.

But even around towns like Hughenden, Julia Creek, Pentland and such, it's not too bad either. The Towers and Ravenswood have the problem of a few mines hanging about, but even there you can get good sky if you travel out of town a bit. A few K's out of town and it's great, although even backyard obs would do well in town as the light pollution is minimal, especially on the outskirts of town.