Lensing in its strong form results in some striking images, but it is relatively rare. Another technique that is more subtle but more widely available, called weak gravitational lensing, measures tiny distortions in the shapes of thousands of distant background galaxies caused by foreground concentrations of mass that can be much smaller than what's required for a strong lens. These thousands of measurements can be combined statistically to make a three-dimensional map of mass between the background galaxy and the Earth. 

What makes Rubin Observatory EPO’s formal education program valuable for teachers?

• Investigations only require accessing a webpage. No special software is needed.
• Investigations will be available in English and Spanish.
• User-friendly data exploration tools within the investigations eliminate the need to download data and export it to other programs.

In its first month of operation, the LSST will see more of the Universe than all previous telescopes combined. Its rapid-fire, 3-billion pixel digital camera will open a movie-like window on objects that change or move; its superb images will enable mapping the cosmos in 3D as never before. Surveying the entire sky every few days, LSST will provide data in real time to both astronomers and the public. For the first time, everyone can directly participate in our journey of cosmic discovery.

The image below, which comes from a pilot project called the Deep Lens Survey (DLS), gives a taste of what the sky will look like with LSST. This image covers the area of the full moon, or half a degree. The DLS images are deep, showing roughly ten times as many galaxies per unit area than the Sloan Digital Sky Survey (SDSS), but the LSST data will actually go deeper still. LSST will also have better resolution than the SDSS as it has been designed from the ground up to minimize blurring, unlike many of today's telescopes.

Focal Plane Requirements

• High QE to 1000nm
• Thick silicon (> 100 µm)
• PSF << 0.7 arcseconds
  • High internal field in the sensor
  • High resistivity silicon substrate (> 5 kohm/cm)
  • High applied voltages (40 - 50 Volts)
  • Small pixel size (0.2 arcseconds = 10 µm)
• Fast f/1.2 focal ratio
  • Sensor flatness < 5µm p-v
  • Package with piston, tip, tilt adj.

The charge-coupled device (CCD) sensors that make up the LSST Camera's focal plane are mounted on 21 platforms called rafts, with each raft comprising a 3x3 square of sensors, for a total of 189 CCDs. Each CCD is built up of 4096 horizontal and 4097 vertical (4K x 4K) imaging elements, and has 16 outputs, adding up to a total of 144 channels per raft and 3024 channels across the entire focal plane array.

The LSST Camera's focal plane is the area across which light from the telescope's mirrors, further corrected by the telescope's lenses, comes to a focus. As such the focal plane is the heart of the camera, responsible for capturing the light from billions of distant galaxies in a form that can be preserved.