Smoke rises above the dome of the William Herschel Telescope on Saturday. Photo: Robin Clark.

Astronomers trying to learn more about the apparent demise of Comet LINEAR were forced to abandon their work this weekend as a forest fire threatened the cluster of telescopes atop La Palma in the Canary Islands.

The blaze began on the mountain at around 5 p.m. local time on Saturday. Within hours it was clear that the mountain-top Roque de las Muchachos Observatory was in danger. Following safety procedures to the letter, all telescopes were evacuated and the staff gathered in a central building.

Dr Mark Kidger, the astronomer who first reported the disintegration of Comet LINEAR, even found himself detailed to operate a radio, relaying messages between fire-fighting teams.

Unfortunately, the comet was no longer within reach of the Jacobus Kapteyn Telescope by the time it was declared safe to return to the telescopes around midnight.

Efforts to contain the fire were thwarted on Sunday, as high winds spread the flames. Although the observatory itself stands beyond the tree line, the rugged landscape is covered with highly inflammatory scrub vegetation. So, fire fighters and observatory staff doused the ground around the nearest buildings, as a preventative step in case the fire broke out from the forest.

By Sunday evening, 7,400 acres of the mountainside where either burnt or burning but the blaze could not be contained, even though more than 500 people were fighting against it. That night the observatory was completely evacuated and so no observations of the fascinating comet were possible.

Smoke from the fires seen from the doorway of an observatory building. Photo: Robin Clark.

Finally, the tide turned for the fire fighters today and by late afternoon, the forest fire was brought under control. No one had been hurt and the observatory was undamaged.

Ricardo Rivero, the observatory's site manager, speaking to Astronomy Now by telephone, paid special tribute to the island's official fire fighters and their efforts to safeguard the observatory.

"It was a great collaboration, we helped them, they helped us," said Rivero.

Rivero summed up the observatory's good fortune. "I estimate the fire came no closer than 1000 metres. No one from the observatory was in any critical danger during the fire."

The wild fire struck in the midst of the most important observations of Comet LINEAR. On the evening of July 25, Dr Kidger noticed on images taken with the JKT one metre telescope that the central condensation of the comet had become elongated. He tracked the comet for three nights, noticing that its brightness was dropping quickly, indicating that the comet's nucleus had almost certainly disintegrated.

Dr. Kidger will resume his observations of Comet LINEAR tonight.