Largest lens
LSST Lens L-1, Ball Aerospace, Arizona Optical Systems
United States (Tucson)

The largest high-performance optical lens was built for the Vera C. Rubin Observatory's LSST Camera, and completed in September 2019. This camera uses three massive lenses to collect and focus the light from the 8.4 m (27 ft 6 in), 3-mirror Simonyi Telescope light onto its 3.2-billion-pixel CCD sensor, the largest of which (known as L-1) measures 1.57 m (5 ft 1 in) across. The lens was made by Ball Aerospace and its subcontractor Arizona Optical Systems (both USA).

When completed, the LSST camera will be the largest digital camera ever built – combining these massive lenses with a 3.2 gigapixel sensor and an array of image-processing computers. All these components will be sealed inside an air-tight, refrigerated housing measuring 1.65 m (5 ft 6 in) in diameter, 3 m (9 ft 10 in) in length and weighing around 2,800 kg (6,200 lb).

Within the next few years, the camera will be installed on the Simonyi Telescope at the Vera C. Rubin Observatory (formerly known as the Large Synoptic Survey Telescope), currently under construction on Cerro Pachon in Elqui Province, Chile. This facility is designed to continuously monitor the night sky -- using its huge camera to take up to 15 terabytes of images every night.

The LSST camera, when installed in Chile, will have a field of view of 9.6 square degrees. For context the full moon has an apparent size (when viewed from earth) of just 0.25 square degrees. By imaging large areas of the night sky on a regular basis, astronomers will be able to identify patterns of movement and variations in brightness that might not otherwise be apparent.

Objects which move through the sky include small solar system bodies like asteroids and comets, but nearby stars also make small displacements in angle due to intrinsic velocities and the orbit of the Earth around the Sun. Variations in stellar brightness can be caused by periodic instabilities, the motions of stars around one another in binary systems, and explosive events like novae and supernovae. One of the big mysteries the Vera C. Rubin observatory might be able to solve is the question of whether or not there is another dim and remote planet beyond Neptune – the so-called Planet Nine. Its combination of high resolution and wide field-of-view makes it well equipped to spot what would be a tiny speck, moving almost imperceptibly slowly between the stars.