Last Week for Personalized Golden Gate Bridge Light Show

Inspired by windows reflecting light across the bay, Solar Beacon is an interactive art exhibit set atop the twin towers of the Golden Gate Bridge.Computer controlled mirrors atop the towers can reflect a beam of light to almost anywhere in the Bay Area. Placed in celebration of the Golden Gate Bridge's 75th Anniversary, the installation is the product of collaboration between London based artist Liliane Lijn, Aeronautical Engineers from the Space Sciences Laboratory at U.C. Berkeley, and Golden Gate Bridge Engineers.To activate the beacon, visitors to the Solar Beacon website specify a time for their show, a location, and a height above ground level.  Computers at the Space Sciences Laboratory calculate the precise angle between the sun and the location, and send a control message to the top of the towers. 
The mirrors rotate on command, reflecting a pleasant and twinkling light, far brighter than any artificial spotlight. For a preview of the coverage area, you can visit a speical page. To learn more about signaling long distance using lights, read up on the Scouting project Operation On Target, which aims each year to send messages from the Mexican Border to the Canadian Border, using mirrors alone.
One advantage to lumens is that consumers can get a wider range of brightness. Instead of having to choose between a 100-watt or 75-watt lamp, bulbs using lumens run the gamut, offering a much finer brightness gradient.Energy savings from efficient lamps are also an advantage. An LED lamp is five times more energy efficient than an incandescent lamp.According to the DOE, the operating cost savings a consumer can achieve by switching to an energy efficient bulb is dramatic. For example, the operating cost per year for a 60-watt incandescent bulb is $4.80, a halogen incandescent bulb costs $3.50, a CFL bulb is $1.20 and an LED light is just $1.Beginning this year, on average, light bulbs sold in the U.S. will use 25% to 80% less energy as manufacturers begin flooding the market with new, compliant products.According to the DOE, upgrading 15 inefficient incandescent bulbs could save a homeowner about $50 per year. Since most of the bulbs also have longer life spans, the savings continue into the future. Nationwide, lighting accounts for about 10% of home electricity use. With new EISA standards, U.S. households in total could save nearly $6 billion in 2015.