Thanks to a funding approval from the U.S. Department of Energy Office of Science, construction of the world’s largest digital camera will start soon. The camera will be mounted on the National Science Foundation’s Large Synoptic Survey Telescope (LSST) on a mountain peak in Chile, where it will photograph, in exquisite detail, the southern night sky over the span of a decade. The camera will be assembled at the DOE’s SLAC National Accelerator Laboratory, operated by Stanford University. The sensor was designed by the Brookhaven National Laboratory, founded by University of New York Stony Brook and Battelle, a nonprofit applied science organization.
In this artist's rendition, the LSST primary mirror is seen through the slit of the dome at sunset. Image courtesy of The Large Synoptic Survey Telescope/ Department of Energy
The telescope’s mirror was built in a 6-story workshop beneath the University of Arizona football stadium. The world’s first dual-surface mirror for a telescope was molded in a 33-foot-wide oven at 2200 degrees F out of 22 tons of molten glass. The mirror measures 27' across.
Let’s run the numbers
3,200,000,000 pixels: Your Canon 5DR has 52MP of resolution? Yawn. This thing has 3.2 gigapixels of eye-watering resolution. That is 3200MP.
5.5 x 9.8': The camera is the size of a small car.
The LSST camera is designed to provide a wide field of view with better than 0.2 arcsecond sampling and spectral sampling in five or more bands from 400nm to 1060nm. The camera includes a filter mechanism and, if necessary, shuttering capability. Image courtesy of The Large Synoptic Survey Telescope/ Department of Energy
6,200 pounds: The camera weighs 6,200 pounds. That is more than a small car. With luggage.
201 individual sensors: There are 201 separate custom-built charged-coupled device (CCD) sensors (189 to take photos, 12 for guidance and focusing).
21 submosaics: Each sensor measures 1.5" across, and they are arranged in 3 x 3 grids of 9 sensors separated by creating 21 submosaics. The assembly must be completely flat with no more than a 10-micron tilt in any direction.
250 microns: The distance between each submosaic to minimize light loss between the sensors is 250 microns.
10 microns: The size of each pixel.
0.2 arc-second sampling: This provides optimized pixel sensitivity versus pixel resolution.
25.2 inches: The imaging surface is more than 2' in diameter.
A three-dimensional rendering of the baseline design of the dome with a cutaway to show the telescope within. Image courtesy of The Large Synoptic Survey Telescope/ Department of Energy
3,000 channels of data: The image from each CCD is divided into 16 segments for parallel processing. The 9-sensor submosaics provide 144 read-out points for over 3000 channels of data.
11,000,000,000,000 bits of data per hour: When it is switched on, the telescope will produce 11 trillion bits of data per hour.
6,000,000 gigabytes: All of those trillions of bits add up to 6 million gigabytes per year—the equivalent of taking 800,000 pictures with an 8MP digital camera every night.
200,000,000,000,000,000 bytes: I never heard of a petabyte until today; this thing is expected to produce up to 200 petabytes of data.
1,500 HD TVs: If you wanted to display one of the LSST images, you would need to arrange 1,500 high-definition televisions in your living room. B&H sells HDTVs.
2,000 square feet: The clean room constructed to build the camera measures 2,000 square feet and is 2 stories tall.
15 seconds: Most astronomical telescopes require several minutes to capture an image in the dark of night. LSST will take 15-second exposures due to the fact that it has custom-designed electronics behind every sensor, and the information is getting split into thousands of discrete bits.
$168,000,000: Amount allocated for the construction of the camera, in US dollars.
The LSST’s camera will include a filter-changing mechanism and shutter. This animation shows that mechanism at work, which allows the camera to view different wavelengths; the camera is capable of viewing light from near-ultraviolet to near-infrared (0.3-1 μm) wavelengths. (SLAC National Accelerator Laboratory)
800 panoramic images: The telescope will combine those exposures into 800 panoramic shots every night to track galaxies at the edge of the universe, as well as nearby asteroids roaming the night sky.
5,000,000,000 galaxies: The LSST’s camera will ultimately image 5 billion galaxies in unprecedented details.
8,858 feet: The telescope will be mounted on the Cerro Pachon mountain peak at an altitude of 8858' (2700 m) above sea level.
3.5 degrees: The 3.5° field of view allows the LSST to produce a complete survey of the entire night sky every 3 days.
In one shot, the Large Synoptic Survey Telescope's 3.2-gigapixel camera will capture an area of the sky 40 times the size of the full moon, or almost 10 square degrees of sky. (SLAC National Accelerator Laboratory)
40 moons: The total field of view coverage of the camera could contain 40 full moons.
25 percent: A quarter of the universe is made up of dark matter. To observe its effect on space, the LSST will witness how gravitational lensing bends the light from distant stars.
70 percent: Scientists know the universe is accelerating as it expands. Dark energy, a force that might account for 70 percent of the universe, might be the cause. LSST will be able to measure the expansion and acceleration.
3 dimensions: LSST data, in conjunction with Google Earth, will create a 3D map of the universe and allow anyone with an Internet-connected computer to virtually fly through space.
A baseline design rendering of the LSST Camera with a cut away to show the inner workings. Image courtesy of The Large Synoptic Survey Telescope/ Department of Energy
10 years: The LSST’s survey of the cosmos will take 10 years, starting in 2022.
1 writer: The person writing this article cannot wait to see the photos!
Information provided by the SLAC National Laboratory, Brookhaven National Laboratory, and the LSST website (www.lsst.org).
Please note: This article is for informational purposes only, because we are impressed with the technology. At no time will B&H be selling this camera.