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Key Numbers

LSST System & Survey Key Numbers

This page lists Key Numbers that describe the LSST system and survey and is a subset of numbers available on the LSST Knowledge Base Confluence page.  More detailed information is available in the LSST Overview Paper and Science Requirements Document.  (Page last updated 9/12/15)


Optical System:
  Etendue ( AΩ ) = 319 meter2degrees2
  Field of View =  3.5 degrees (9.6 square degrees)
  Primary mirror diameter =  8.4 m
  Effective clear aperture =  6.68 m (on-axis)
  Mean effective aperture = 6.423 m (area weighted over FOV)
  Final f-ratio =  f/1.234
  Plate scale =  50.9 microns/arcsec

Imaging System:
  Pixel count =  3.2 Gpixels
  Readout time =  2 sec
  Dynamic range =  18 bits
  Pixel pitch = 10 micron (0.2 arcsec)

Spectral Response:
  Full bandpass range = 320-1050 nm
  Total number of filters = 6
  Number of active filters =  5
  System 50% response points (nm)
    u  324  395
    g  405  552
    r   552  691
    i   691  818
    z  818  921
    y  922  997 

Survey Area:
  Fiducial main survey area = 18,000 deg2
  Total covered area (est.) = 25,000 deg^2
    (main survey + special programs)
  Fiducial number of visits per pointing in the main survey = 825

Network bandwidths:
  Summit (Pachón) to Base (La Serena) =  2 x 100 Gbps
  Base(La Serena) to Archive (NCSA) = 2 x 40 Gbps

 

Observation Properties:
  The standard visit = 2 x 15 sec. exposures
  Exposure sequence = 1 s open shutter + 14 s dwell + 1 s close shutter = 16 s
  Visit sequence = 16 s exp + 2 s readout + 16 sec exp = 34 s
  (second readout concurrent with slew)
  Median slew time between visits = 4.8 s
  Mean slew time between visits = 6.8 s
  Visits per night = "about a 1000"
  Calibration exposures = 450/day
  Data collected per 24 hr period = "about 15 TB"

Data Releases:
  Number of Data Releases = 11
  Date of DR1 release = Date of Operations Start+ 12 months
  Estimated numbers for DR-1 release
    Objects = 18 billion
    Sources = 350 billion (single epoch)
    Forced Sources = 0.75 trillion  

  Estimated numbers for DR-11
    Objects = 37 billion
    Sources = 7 trillion (single epoch)
    Forced Sources = 30 trillion
    Visits observed = 2.75 million
    Images collected = 5.5 million

Alert Production:
  Real-time alert latency =  60 seconds
  Average number of alerts per night= "about 10 million"

Data and compute sizes:
  Final image collection (DR11) = 0.5 Exabytes
  Final database size (DR11) = 15 PB
  Final disk storage = 0.4 Exabytes
  Peak number of nodes  = 1750 nodes
  Peak compute power in LSST data centers = 1.8 PFLOPS

Financial support for LSST comes from the National Science Foundation (NSF) through Cooperative Agreement No. 1258333, the Department of Energy (DOE) Office of Science under Contract No. DE-AC02-76SF00515, and private funding raised by the LSST Corporation. The NSF-funded LSST Project Office for construction was established as an operating center under management of the Association of Universities for Research in Astronomy (AURA).  The DOE-funded effort to build the LSST camera is managed by the SLAC National Accelerator Laboratory (SLAC). 


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