PARTS of Australia's biggest observatory, at Siding Spring, west of Coonabarabran, were destroyed by a ''fast moving, large and dangerous'' bushfire on Sunday night, as the fire emergency continued across large areas of NSW.
Two homes also burned down as the fire pushed through Warrumbungle National Park after a sudden change in the wind.
Bushfire damages Australia's largest observatory
A bushfire burning out of control west of Coonabarabran destroyed parts of Australia's largest observatory at Siding Spring on Sunday night.
The extent of the damage at the observatory, which holds the Anglo-Australian Telescope - the nation's biggest - will not be known until Monday morning. The Australian National University, which operates the site, said all staff had made it to safety.
Evacuations took place along a four-kilometre fire front on Sunday night, with people seeking refuge in Coonabarabran as huge columns of smoke filled the sky.
''It looked like an atom bomb the way it went up,'' said Susan Armstrong, who owns a property to the west of the fire. Her husband, Brian, had been fighting the blaze, which started on Saturday, but his crew had to pull back.
''They got sent home. It was far too dangerous,'' Mrs Armstrong said. ''He said the spot fires and how quickly it all moved was quite scary.''
Rural Fire Service Superintendent Matt Inwood said fire crews were battling fierce conditions.
''At the moment it is 36 degrees and the south-westerly winds are gusting at 63km/h,'' he said. ''Strong winds are making fighting the fire very challenging because it moves very quickly.
''It's a large, fast-moving fire, so all of the properties in that area are in great danger,'' Superintendent Inwood said. ''There are another 12 properties in the area and they were all sent alert telephone messages to evacuate.''
He said there were 48 firefighters tackling the fire and 10 RFS aircraft were also working to extinguish it.
Brian Schmidt, a Nobel laureate and celebrated ANU astronomer, posted a statement online about the obervatory's fate.
''I have had what has to be a quintessential experience of the current era - watching a firefront pass through Siding Spring Observatory live via the internet, using all of the remote observing information we have on various telescopes, while getting simultaneous news and views via Twitter,'' Professor Schmidt said.
''I fear a lot of damage has been done … even if not the wholesale destruction we faced in 2003 at Mount Stromlo Observatory. Tomorrow will tell and then will come the long, slow process of recovery.''
Meanwhile, a cool change has brought relief to NSW Rural Fire Service officers fighting bushfires in other areas. On Sunday, more than 190 firefighters were working to contain a bushfire burning 12 kilometres west of Sussex Inlet, on the south coast. The fire has burnt more than 8400 hectares but there is no immediate threat to properties.
The latest blast of heat from Australia's hot heart sent the mercury soaring over the weekend in parts of western NSW and in Queensland. Walgett touched 48.5 degrees and nearby Bourke 48. Tibooburra Post Office's 47.9 degrees was the highest in 103 years of records.
''Once we get to Tuesday to Thursday of [this] week, the interior could be just as hot as today,'' Brett Dutschke, senior meteorologist at Weatherzone, said.