LOISOS + UBBELOHDE : Architecture . Energy  
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The historic coelostat designed by Russell Porter in 1934 on the CalTech campus was restored and modernized as part of the overall laboratory building restoration. Resilvered mirrors were reactivated and programmed to once again track the solar disc. Reflected sun is beamed down the original octagonal shaft providing a real time image of the sun, direct beam for climate research, and light for fiber optic fixtures in below grade laboratories.

Photo of coelostat and beam of light travelling down the shaft.

Diagram of restored coelostat

The coelostat directs a 24'' diameter column of light to the basement of the buidling, illuminating eight solar light fixures and providing a free beam of direct sun for scientic research.

Fiber optic fixtures installed in the basement.

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Loisos + Ubbelohde

Telescope Restoration
Dick Treffers

Pasadena, CA
In operation since 2012
2009 AIA East Bay Unbuilt Merit Design Award for Coelostat Re-Activation

Above: Daylight luminating the hallway.

Above: Fiber optics light fixture components test.

Above: Mock up of fiber optics light fixture powered by sunlight delivered by the coelostat

Above: Detail of fiber optics

Above: Fiber Optics in laboratory

Above: Live coelostat image of sun