The wildfire threat to historic Mount Wilson Observatory seems to have subsided, though firefighters are still wary of the blaze, which has burned more than 144,000 acres.
The so-called Station fire has been burning through Angeles National Forest for more than a week now. The fire began to creep up the slopes of Mount Wilson, toward the observatory and communications towers at its peak, over the weekend, after retreating from the nearby NASA Jet Propulsion Laboratory.
The 100-year-old observatory was founded in 1904 by George Ellery Hale, who used solar telescope observations made there to prove that sunspots were areas of lower temperature on the sun's surface. Edwin Hubble also used observations made at Mount Wilson to show that the Milky Way is only one of many galaxies and that the universe is expanding.
The history of the observatory, and the modern astronomy projects still carried out there, were under threat for several days as the flames of the rapidly intensifying wildfire crept closer to the outpost's structures.
To keep the fire from reaching the peak, firefighters dug fire lines, cleared brush and dumped fire retardant chemicals from the air in the woods surrounding the observatory.
On Monday and Tuesday, the outlook was grim, but by Wednesday cooler temperatures and higher humidity had forced the flames back. The threat still isn't gone, but firefighters sound more optimistic than in days past.
"We're pretty confident," Los Angeles County Fire Inspector Edward Osorio told the L.A. Times. "Mt. Wilson is going to be OK."
Observatory officials are staying cautious though. The latest update to the observatory website, made Wednesday afternoon, read, "The fire to the north, against which all the back fires and preparation of last night were mounted, still lurks. I remain optimistic, but we cannot declare the end to any danger until the fire is declared contained by authorities."
Fire containment, which sits at 38 percent now according to news reports, is not expected to be fully achieved until Sept. 15.