The world’s largest optical lens will photograph the stars of the southern sky in 2023

The lens took over five years to build.

team with the largest optical lens ever fabricated
The largest high-performance optical lens ever fabricated (5.1 feet in diameter) has arrived at a clean room at SLAC, where the lab assembles the 3,200-megapixel digital camera of the Large Synoptic Survey Telescope (LSST). The lens is mounted with a smaller companion lens (3.9 feet in diameter) in a carbon fiber structure. Both lenses have been built over the past five years by Boulder, Colorado-based Ball Aerospace and Technologies Corp. and its subcontractor, Tucson-based Arizona Optical Systems.Farrin Abbott/SLAC National Accelerator Laboratory

Camera lenses aren't always complicated, you can make one by simply punching a tiny pinhole in an old cardboard box. But, have to admit that we love a massive lens filled with glass components. The enormous chunk of glass pictured above is the largest optical lens in the world. It measures 5.1 feet across and will eventually reside on a $168 million dollar, 3,200-megapixel digital telescope camera created for the LSST to photograph the southern sky.

massive optical lens
This massive optical lens will be used with 3,200-megapixel digital camera of the Large Synoptic Survey Telescope to photograph the southern sky.Farrin Abbott/SLAC National Accelerator Laboratory

The biggest lens will actually be mounted alongside two other smaller lenses on the telescope—a lens with a diameter of 3.9 feet and one with a diameter of 2.36 feet. Last month two of the three lenses arrived at a laboratory in Menlo Park that is overseeing the fabrication of the massive telescope.

When the project is done the 27.5 foot telescope will be taking digital images of the entire visible southern sky for the next 10 years. It's estimated that the telescope will be able to detect approximately 20 billion galaxies and give scientists a better understanding of the dark matter that makes up the majority of the universe. The images produced by the telescope will be so high resolution that it would take 1500 high-def screens to show a single picture.