1. Science Based System Requirements 
    1. 1 Survey Specifications 
      1. 1.1 Filter Set Characteristics 
      2. 1.2 Single Image Performance 
        1. 1.2.1 r-bandRefDepth 
        2. 1.2.2 filterDepths 
        3. 1.2.3 imageQuality 
        4. 1.2.4 imageEllipticity 
        5. 1.2.5 astrometricPerformance 
        6. 1.2.6 photometricPerformance 
        7. 1.2.7 brightSources 
      3. 1.3 Full Survey Performance 
        1. 1.3.1 skyCoverage 
        2. 1.3.2 overallEllipticityCorrelations 
        3. 1.3.3 dataProcessing 
    2. 2 System Capabilities 
      1. 2.1 Optical Configuration 
        1. 2.1.1 Effective Aperture 
        2. 2.1.2 Field Of View 
        3. 2.1.3 Recorded Etendue 
        4. 2.1.4 Atmospheric Dispersion Correction 
        5. 2.1.5 System Image Quality 
        6. 2.1.6 Variation in Image degradation 
        7. 2.1.7 Stray and Scattered Light 
          1. 2.1.7.1 Anti-Reflection Coatings 
          2. 2.1.7.2 Baffling 
        8. 2.1.8 Science Instrument 
      2. 2.2 Data Collection 
        1. 2.2.1 Science Data 
          1. 2.2.1.1 Standard Visit 
          2. 2.2.1.2 Time Interval Between Visits 
          3. 2.2.1.3 System Throughput 
        2. 2.2.2 Calibration Data 
        3. 2.2.3 Engineering Data 
        4. 2.2.4 Ancillary Data 
      3. 2.3 Data Products & Processing 
        1. 2.3.1 Calibrated Image Production 
        2. 2.3.2 Catalog Production 
        3. 2.3.3 Data Products 
          1. 2.3.3.1 Level 1 Data Products 
          2. 2.3.3.2 Level 2 Data Products 
          3. 2.3.3.3 Level 3 Data Products 
          4. 2.3.3.4 Calibrated Single Images 
          5. 2.3.3.5 Calibration Data Products 
          6. 2.3.3.6 Science Database 
        4. 2.3.4 Optical Transient Alert Generation 
          1. 2.3.4.1 Alert Generation Latency 
          2. 2.3.4.2 Alert Generation Reliability 
      4. 2.4 Data Archiving & Services 
        1. 2.4.1 Raw Image Data Archiving 
        2. 2.4.2 Data Product Archiving 
        3. 2.4.3 Engineering and Environmental Data Archiving 
        4. 2.4.4 Data Product Open Access 
          1. 2.4.4.1 Data Distribution 
          2. 2.4.4.2 Data Product Access Interface 
        5. 2.4.5 Community computing services 
    3. 3 Survey Operation & Administration 
      1. 3.1 Operational Safety 
      2. 3.2 Public Data Release 
        1. 3.2.1 Data Quality Metrics 
      3. 3.3 Science Priorities & Survey Scheduling 
        1. 3.3.1 Scientific Priority 
        2. 3.3.2 Adjustment of Survey Priorities 
        3. 3.3.3 Survey Performance Reviews 
        4. 3.3.4 Survey Simulation 
      4. 3.4 Observatory Control 
        1. 3.4.1 Central Administration 
        2. 3.4.2 Process Command and Control  
        3. 3.4.3 Local Administration 
        4. 3.4.4 Scientific & Technical Process Monitoring 
        5. 3.4.5 Scientific Oversight During Data Collection 
        6. 3.4.6 Autonomous Operation 
      5. 3.5 Overall Operational Efficiency 
        1. 3.5.1 Graceful Degradation 
        2. 3.5.2 Survey Time Allocation 
        3. 3.5.3 System Operational Lifetime 
        4. 3.5.4 Preventive Maintenance 
      6. 3.6 Education & Public Outreach 
      7. 3.7 Existing Infrastructure 
   

 





Document Change Log
Handle:   LSE-29  
  Creation Date: 2010-02-16
  Author(s): C. F. Claver
 
Revision Author(s)
Revision Date
Description of Changes
C. F. Claver
2/23/2010
Fixed typos, added governing safety requirement
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     

 


Table of Contents
 

Document Change Log 2
Science Based LSST System Requirements 5
1 Survey Specifications 6
1.1 Filter Set Characteristics 6
1.1.1 filterComplement 6
1.1.2 bandpassPerformance 6
1.2 Single Image Performance 7
1.2.1 r-bandRefDepth 7
1.2.2 filterDepths 7
1.2.3 imageQuality 8
1.2.4 imageEllipticity 9
1.2.5 astrometricPerformance 9
1.2.6 photometricPerformance 10
1.2.7 sourceBrightnessHeadroom 11
1.3 Full Survey Performance 11
1.3.1 skyCoverage 11
1.3.2 overallEllipticityCorrelations 12
1.3.3 dataProcessing 12
2 System Capabilities 14
2.1 Optical Configuration 14
2.1.1 Effective Aperture 14
2.1.2 Field Of View 15
2.1.3 System Etendue 15
2.1.4 Atmospheric Dispersion Correction 15
2.1.5 System Image Quality 15
2.1.6 Stray and Scattered Light 16
2.1.6.1 Anti-Reflection Coatings 16
2.1.6.2 Baffling 17
2.1.7 Science Instrument 17
2.2 Data Collection 17
2.2.1 Science Data 17
2.2.1.1 Standard Visit 17
2.2.1.2 Time Interval Between Visits 18
2.2.1.3 System Throughput 18
2.2.1.3.1 Average System Response 18
2.2.1.3.2 Throughput variation with time 20
2.2.1.3.3 Vignetting Function 20
2.2.2 Calibration Data 20
2.2.3 Engineering Data 20
2.2.4 Ancillary Data 21
2.3 Data Products & Processing 21
2.3.1 Calibrated Image Production 21
2.3.2 Catalogue Production 21
2.3.3 Data Products 21
2.3.3.1 Level 1 Data Products 22
2.3.3.1.1 Data Quality Monitoring 22
2.3.3.2 Level 2 Data Products 22
2.3.3.2.1 Data Quality Monitoring 22
2.3.3.2.2 Frequency of Data Releases 23
2.3.3.2.3 Scientific Content 23
2.3.3.3 Level 3 Data Products 23
2.3.3.4 Calibrated Single Images 23
2.3.3.5 Calibration Data Products 24
2.3.3.6 Science Database 24
2.3.4 Optical Transient Alert Generation 24
2.3.4.1 Alert Generation Latency 24
2.3.4.2 Alert Generation Reliability 24
2.4 Data Archiving & Services 25
2.4.1 Raw Image Data Archiving 25
2.4.2 Data Product Archiving 25
2.4.3 Engineering and Environmental Data Archiving 25
2.4.4 Data Product Open Access 25
2.4.4.1 Data Distribution 26
2.4.4.2 Data Product Access Interface 26
2.4.5 Community computing services 26
3 Survey Operation & Administration 27
3.1 Education & Public Outreach 27
3.2 Existing Infrastructure 27
3.3 Observatory Control 27
3.3.1 Central Administration 28
3.3.2 Local Administration 28
3.3.3 Scientific Oversight During Data Collection 28
3.3.4 Autonomous Operation 28
3.4 Public Data Release 29
3.4.1 Data Quality Metrics 29
3.5 Science Priorities & Survey Scheduling 29
3.5.1 Scientific Priority 29
3.5.2 Adjustment of Survey Priorities 29
3.5.3 Survey Performance Reviews 30
3.5.4 Survey Simulation 30
3.6 Overall Operational Efficiency 30
3.6.1 Graceful Degradation 30
3.6.2 Survey Time Allocation 30
3.6.3 System Operational Lifetime 31
3.6.4 Preventive Maintenance 31
  
Science Based System Requirements  

Project Background:
 
The LSST is a large-aperture, wide-field, ground-based telescope that will survey the visible sky every few nights in six photometric bands. The 10-year survey will produce a database suitable for answering a wide range of pressing questions in astrophysics, cosmology, and fundamental physics. LSST is designed to be a public facility. The images, alerts, and resulting catalogs will be made available to the community at-large with no proprietary period. A sophisticated data management system will provide easy access to these data, enabling simple queries from individual users (both professionals and laypersons), as well as computationally intensive scientific investigations that utilize the entire database.
 
Document Scope:
 
This Science Based System Requirements (SBSR) document provides a comprehensive definition of the LSST Observatory system requirements. It is derived from the LSST Science Requirements Document [LSST LPM-17] that describes the scientific motivations for the project, the survey capabilities and the reference science missions used to develop detailed scientific specifications for the LSST survey. This document builds on those to fully describe the specific nature of the LSST survey, final data products, and derived system finctions and specifications that must be met in the execution of the LSST project.
 
These requirements cover the following areas:
 
·   Adopted survey performance parameters from the SRD
·   Inherited technical requirements from the SRD
·   System definitions for
1) Optical Configuration
2) Data collection functions and performance
3) Data processing functions and performance
4) Archiving and services functions and performance

·   Survey planning and administration functions
 
Reference Documents:
 
1.   The LSST Science Requirements Document (v4.3.3)
2.   The Observatory System Specifications
 
 

 


1 Survey Specifications  

id:    
Version:  1.0 Modified:  2/17/2010 Status:  Proposed

Specification: The LSST system shall be designed such that the system achieves a survey with the following and scientific and performance specifications.
 
Discussion: The LSST SRD specifies a suite of requirements for the scientific performance of the survey with minimum, design, and stretch goals. For the purpose of establishing the system design and flow down to lower level requirements and specifications a single value for these specifications must be adopted.
 
The specifications that follow establish which specific value for each of the SRD performance parameters have been adopted within their defined ranges for the system design. At this time the SRD design specifications have been adopted for each parameter.
 
 

 


1.1 Filter Set Characteristics  
id:    
Version:  1.0 Modified:  2/16/2010 Status:  Proposed

Specification: The LSST survey shall provide imaging in 6 spectral bandpasses that are defined in the following specifications for the filterComplement and the bandpassPerformance.

 
Discussion: The specifications for internal filter exchange and change-out are located in the Observatory System Specifications Document under the Camera Dynamics and Timing requirements.
Description
Value
Unit
Attribute
The filter set to be used during the lifetime of the survey shall consist of at least 6 filters, FC, providing a sampling across the optical spectrum.
ugrizy
 
FC
The total number of filters available on a nightly basis shall be NFilters.
5
 
NFilters
Description
Value
Unit
Attribute
The maximum out of band leakage in an 10nm interval shall be no more than FLeak relative to the peak filter response outside one FWHM from the central wavelength.
0.01
Percent
FLeak
The total integrated leak shall be less than FLeakTot relative to the total transmission.
0.05
Percent
FLeakTot
The temporal stability of the filter bandpasses shall be sufficiently small such that the required photometric calibration specifications can be met.
TBR
 
temporalStability


1.2 Single Image Performance  
id:    
Version:  1.0 Modified:  2/9/2010 Status:  Proposed

Specification: The LSST shall meet the following specifications for single image performance:
 
1.   Delivered Image Quality
2.   Photometric Performance
3.   Astrometric Performance
4.   Image Depth
 

 


1.2.1 r-bandRefDepth  
Version:  1.0 Modified:  2/10/2010 Status:  Proposed
Description
Value
Unit
Attribute
The reference airmass under which the depth specification shall be met is refAirmass.
1.0
Airmass
refAirmass
The reference exposure time for which the single image depth specifications shal be met is refExposureTime.
30
Seconds
refExposureTime
The reference atmospheric seeing for which the depth specifications shall be met is refSeeing as measured in the r-band.
0.7
ArcsecFWHM
refSeeing
The reference sky surface brightness for which the depth specifications shall be met is refSkyBrightness as measured in the r-band.
21
mag/SqArcsec
refSkyBrightness
The r-band 5-sigma limiting magnitude shall be no brighter than DT1 for unresolved point sources.
24.7
ABmag
DT1
The fraction of the field of view with a 5-sigma point source detection depth brighter than the depth outlier limit (Z1) shall be no more than DF1.
10
Percent
DF1
The outlier limit for 5-sigma point source detection depth shall be no brighter than Z1.
24.4
ABmag
Z1


1.2.2 filterDepths  
Version:  1.0 Modified:  2/10/2010 Status:  Proposed
Description
Value
Unit
Attribute
u-band point source 5-sigma detection depth shall be no brighter than
23.9
ABmag
DB1u
g-band point source 5-sigma detection depth shall be no brighter than
25.0
ABmag
DB1g
r-band point source 5-sigma detection depth shall be no brighter than
24.7
ABmag
DB1r
i-band point source 5-sigma detection depth shall be no brighter than
24.0
ABmag
DB1i
z-band point source 5-sigma detection depth shall be no brighter than
23.3
ABmag
DB1z
v-band point source 5-sigma detection depth shall be no brighter than
22.1
ABmag
DB1y


1.2.3 imageQuality  
Version:  1.0 Modified:  2/9/2010 Status:  Proposed
Description
Value
Unit
Attribute
Median system delivered image quality in atmospheric seeing of 0.44 arcseconds in the r and i filters.
0.56
ArcsecFWHM
S1_0.44
Median system delivered image quality in atmospheric seeing of 0.60 arcsec in the r and i filters.
0.69
ArcsecFWHM
S1_0.60
Median system delivered image quality in atmospheric seeing of 0.80 arcseconds in the r and i filters.
0.87
ArcsecFWHM
S1_0.80
The maximum quadrature contribution from the LSST system to the atmospheric seeing referenced at zenith or airmass (sec(zd)) = 1.
0.35
ArcsecFWHM
SysIm_0
The maximum quadrature contribution from the LSST system to the atmospheric seeing referenced at zenith distance of 45 degrees or airmass (sec(zd)) = 1.4.
0.42
ArcsecFWHM
SysIm_45
The maximum quadrature contribution from the LSST system to the atmospheric seeing referenced at zenith distance of 60 degrees or airmass (sec(zd)) = 2.0.
0.52
ArcsecFWHM
SysIm_60
Delivered image quality increase factor allowed over SF1 fraction of the field of view.
1.1
float
SX
The maximum fraction of the field of view that can exceed the delivered image size by a factor of SX.
10
Percent
SF1
The minimum number of pixels across the FWHM of the delivered PSF under median atmospheric conditions (0.6 arcsec FWHM) shall be
3
Pixels
PSFSample
The system image budget is allowed to degrade through the three reference zenith distances (zd) as sec(zd)^ ImFunc.
0.6
 
ImFunc
The maximum diameter of the PSF spatial profile containing 80 percent encircled energy.
0.76
Arcsec
SR1
The maximum diameter of the PSF spatial profile containing 90 percent encircled energy.
1.17
Arcsec
SR2
The maximum diameter of the PSF spatial profile containing 95 percent encircled energy.
1.62
Arcsec
SR3


1.2.4 imageEllipticity  
Version:  1.0 Modified:  2/10/2010 Status:  Proposed
Description
Value
Unit
Attribute
The maximum median raw PSF ellipticity over the full field of view in a single 15 second exposure for bright isolated non-saturated stars.
0.04
Ellipticity
SE1
The maximum PSF raw ellipticity limit.
0.07
Ellipticity
SE2
The fraction of PSF ellipticity measurements allowed to exceed the ellipticity outlier limit for bright isolated non-saturated stars.
5
Percent
EF1
The maximum residual ellipticity correlation amplitude over 1 arcmin scales.
2.0e-4
 
SE3
The maximum residual ellipticity correlation amplitude over 5 arcmin scales.
5.0e-7
 
SE4
The maximum median residual ellipticity amplitude outlier limit on scales less than or equal to 1 arcmin.
4.0e-4
 
SE5
The maximum median residual ellipticity amplitude outlier limit on scales between 1 and 5 arcmin.
1.0e-6
 
SE6
Fraction of allowed PSF measurements of isolated bright stars to exceed the ellipticity residual correlation amplitude outlier limit.
10
Percent
EF2


1.2.5 astrometricPerformance  
Version:  1.0 Modified:  2/9/2010 Status:  Proposed
Description
Value
Unit
Attribute
Median error in absolute position for each axis, RA & DEC, shall be less than AA1.
50
mili-Arcsec
AA1
Median relative astrometric measurement error on 5 arcminute scales shall be less than AM1.
10
mili-Arcsec
AM1
5 arcminute outlier limit.
10
mili-Arcsec
AD1
Fraction of relative astrometric measurements on 5 arcminute scales to exceed 5 arcminute outlier limit.
10
Percent
AF1
Median relative astrometric measurement error on 20 arcminute scales.
10
mili-Arcsec
AM2
20 arcminute outlier limit.
20
mili-Arcsec
AD2
Fraction of relative astrometric measurements on 20 arcminute scales to exceed 20 arcminute outlier limit.
10
Percent
AF2
Median relative astrometric measurement error on 200 arcminute scales.
15
mili-Arcsec
AM3
200 arcminute outlier limit.
30
mili-Arcsec
AD3
Fraction of relative astrometric measurements on 200 arcminute scales to exceed 200 arcminute outlier limit
10
Percent
AF3
RMS difference between separations measured in the r-band and those measured in any other filter.
10
mili-Arcsec
AB1
The color difference outlier limit for separations measured relative the r-band filter in any other filter..
20
mili-Arcsec
AB2
Fraction of separations measured relative to the r-band that can exceed the color difference outlier limit.
10
Percent
ABF1


1.2.6 photometricPerformance  
Version:  1.0 Modified:  2/9/2010 Status:  Proposed
Description
Value
Unit
Attribute
The RMS photometric repeatability of bright non-saturated unresolved point sourses in the g, r, and i filters.
5
mili-Mag
PA1gri
The RMS photometric repeatability of bright non-saturated unresolved point sourses in the u, z, and y filters.
7.5
mili-Mag
PA1uzy
Repeatability outlier limit for isolated brigh non-saturated pointsources in the g, r, and i filters.
15
mili-Mag
PA2gri
Repeatability outlier limit for isolated brigh non-saturated pointsources in the u, z, and y filters.
22.5
mili-Mag
PA2uzy
Fraction of isolated non-saturated point source measurements exceeding the outlier limit.
10
Percent
PF1
RMS width of internal photometric zero-point (precision of system uniformity across the sky) for all bands except u-band.
10
mili-Mag
PA3
The zero point error outlier limit.
15
mili-Mag
PF4
Fraction of zeropoint errors that can exceed the zero point erro outlier limit.
10
Percent
PF2
Accuracy of absolute band-to-band color zero-point for all colors constructed any filter pair except u-band.
5
mili-Mag
PA5
Accuracy of absolute band-to-band color zero-point for colors constructed using the u-band.
10
mili-Mag
PA5u
Accuracy of the transformation of the internal LSST photometry to a physical scale (e.g. AB magnitudes).
10
mili-Mag
PA6
Fractional increase in the photometric error over repeated measurements for isolated bright non-saturated point sources.
10
Percent
EPErr
Percentage of image area that can have ghosts with surface brightness gradient amplitude of more than 1/3 of the sky noise over 1 arcsec.
1
Percent
GhostAF
The maximum local significance integrated over the PSF of imperfect crosstalk corrections.
3
Sigma
Xtalk
Thye maximum fraction of pixels scientifically unuseable per sensor out of the total allowable fraction of sensors meeting this performance.
1
Percent
PixFrac
The maximum allowable fraction of sensors with PixFrac scientifically unusable pixels.
15
Percent
SensorFraction
The maximum error in the precision of the sky brightness determination.
1
Percent
SBPrec
Maximum rms ratio of the error between resolved sources less than 10 arcsec in diameter to unresolved point sources.
2
 
ResSource


1.2.7 brightSources  
Version:  1.0 Modified:  2/17/2010 Status:  Proposed
Description
Value
Unit
Attribute
The LSST shall be capable of unsaturated measurements of sources brighter than the nominal 15-second saturation limit by at least brightSource.
1.0
ABmag
brightSource


1.3 Full Survey Performance  
id:    
Version:  1.0 Modified:  2/17/2010 Status:  Proposed

Specification: Integrated over all survey observations made over a 10 year period the LSSt shall meet all specifications for skyCoverage, overallEllipticityCorrelations, and dataProcessing.

 


1.3.1 skyCoverage  
isEncapsulated:    
Version:  1.0 Modified:  2/10/2010 Status:  Proposed

 
Description
Value
Unit
Attribute
The total area of sky covered by the median number of visits shall be no less than
18000
SquareDegrees
Asky
The median number of visits for each place of the sky within the main survey area shall be at least
825
Visits
Nv1Sum
The area of sky covered with uniformly sampled time scale between 40 seconds and 40 minutes shall be at least
2000
SquareDegrees
RVA1
The total area of sky that is covered with at least 25% of the total number of visit separated by more than 5 years shall be at least
15000
SquareDegrees
RVA2
The total area of sky that is covered with at least 25% of the total number of visit spanning at least 4 calendar months shall be at least
15000
SquareDegrees
RVA3


1.3.2 overallEllipticityCorrelations  
Version:  1.0 Modified:  2/10/2010 Status:  Proposed
Description
Value
Unit
Attribute
Median residual PSF ellipticity correlations averaged over an arbitrary field of view for separations less than 1 arcmin shall be no greater than
2.0e-5
 
TE1
Median residual PSF ellipticity correlations averaged over an arbitrary field of view for separations less than 5 arcmin shall be no greater than
1.0e-7
 
TE2
The outlier limit on the PSF ellipticity correlation residuals on 1 arcminute scales shall be no more than
4.0e-5
 
TE3
The outlier limit on the PSF ellipticity correlation residuals on 5 arcminute scales shall be no more than
2.0e-7
 
TE4
The fraction of PSF ellipticity correlation residuals that can exceed the outlier limits on 1 and 5 arcminutes scales over an arbitrary field of view shall be no more than
15
Percent
TF1


1.3.3 dataProcessing  
Version:  1.0 Modified:  2/10/2010 Status:  Proposed
Description
Value
Unit
Attribute
The letency of reporting optical transients following the readout of the last image of a visit shal be no more than
1
Minute
OTT1
The transient reporting capacity shall be at least transN alerts per visit .
1.0e4
 
transN
The interval between standardized data releases shall be no breater than
1
Years
DRT1


2 System Capabilities  

id:    
Version:  1.0 Modified:  2/15/2010 Status:  Proposed

Specification: In order to perform a survey as defined above and present the data in a scientifically usefull manner the LSST Observatory shall be a complete system that:
 
1.   obtains survey data in the form of digital images,
2.   processes, calibrates, and archives the images,
3.   generates source and object catalogs,
4.   makes all data and data products available to a wide range of users.
 
Discussion: The requirements that define the system capabilities have been organized into 4 groupings that characterize the high level performance and functional reqirements that must be met. The 4 groupings include:
 
1.   The Optical Configuration: These requirements specifiy the type of optical design, feild of view, effective aperture, and overall system throughput that are derived from the SRD.
2.   Data Collection: These requirements specify in broad terms the data collection functions the LSST system must have in order to conduct the specified survey, optimize its operation, and record knowledge of the its physical state during routine operation.
3.   Data Products & Processing: These requirements specifiy the high-level definition of the LSST data products to be delivered to the user community and what process must occur to create these products.
4.   Data Archiving and Services: These requirements define the high-level archiving and data delivery functions that are needed to deliver the LSST data and Data Products to its intended user base. Also included are the definitions of other data processing services that will beprovided by the LSST system.
 

 


2.1 Optical Configuration  
id:    
Version:  1.0 Modified:  2/17/2010 Status:  Proposed

Specification: The LSST optical configuration shall be from the anastigmatic class of optical designs.
 
Discussion: The anastigmatic design class eliminates 3rd order astigmatism across the field of view.

 


2.1.1 Effective Aperture  
id:    
Version:  1.0 Modified:  2/17/2010 Status:  Proposed

Specification: The effective light collecting area of the LSST shall be equivelent to clear unobstructed circular aperture of at least that of effAperture.

 
 
Description
Value
Unit
Attribute
The aperture diameter equivalent to 33.2 square meters of collecting area.
6.5
Meters
effAperture


2.1.2 Field Of View  
id:    
Version:  1.0 Modified:  2/4/2010 Status:  Proposed

Specification: The field of view of the LSST optical system shall be at least fieldOfView in diameter.

 
Description
Value
Unit
Attribute
The diameter of the field of view equivelent to 9.6 square degrees of sky coverage.
3.5
Degrees
fieldOfView


2.1.3 Recorded Etendue  
id:    
Version:  1.0 Modified:  2/17/2010 Status:  Proposed

Specification: The LSST optical system shall have a etendue (effective collecting area integrated over the field of view x area recorded in each image ) of at least etendueRec.

 
 
Description
Value
Unit
Attribute
The effective collecting area integrated over the field of view * field of view area recorded in each image.
300
Etendue
etendueRec


2.1.4 Atmospheric Dispersion Correction  
id:    
Version:  1.0 Modified:  2/17/2010 Status:  Proposed

Specification: An atmospheric dispersion corrector (ADC) is not required in the LSST system design.
 
Discussion: The project under took a detailed trade study during the early conceptual phase of the project to determine if an ADC is needed and if it was even feasible to design and build an ADC large enough to accommodate the LSST field of view. This trade study concluded that an ADC was feasible but was not necessary provided that the survey observations we kept above 1.4 airmasses for the science needing the most control of the PSF shape. The minimum survey area of 15000 square degrees is achievable while staying above 1.4 airmasses. (Documentation relating to this study is contained in Collection-894 on the LSST Document Archive).   https://www.lsstcorp.org/docushare/dsweb/View/Collection-894  

 


2.1.5 System Image Quality  
id:    
Version:  1.0 Modified:  2/17/2010 Status:  Proposed

Specification: At the reference atmospheric seeing of 0.6 arcsec FWHM the 10% degradation results in an allocation for the RSS system image blur of medainRMSBudget.
 

 
Description
Value
Unit
Attribute
The RMS of the total RSS contribution to the atmospheric seeing from the opto-mechanical system and detectors under the median atmospheric conditions.
0.35
ArcsecFWHM
medianRMSBudget


2.1.6 Variation in Image degradation  
id:    
Version:  1.0 Modified:  2/17/2010 Status:  Proposed

Specification: The image degridation over the field of view shall be smooth and small compared to the atmospheric seeing such that 10 percent of the filed of view shall be allowed to exceed a total RSS system image blur budget of
 
10%outlierBudget_0.44 in first quartile atmospheric seeing
10%outlierBudget_0.60 in median atmospheric seeing
10%outlierBudget_0.80 in third quartile atmospheric seeing

 
Description
Value
Unit
Attribute
The limiting RSS image blur that can be exceeded by 10% of the field of view in the first quartile (0.44 arcsec FWHM) atmospheric seeing conditions.
0.43
ArcsecFWHM
10%outlierBudget_0.44
The limiting RSS image blur that can be exceeded by 10% of the field of view in the median (0.60 arcsec FWHM) atmospheric seeing conditions.
0.46
ArcsecFWHM
10%outlierBudget_0.60
The limiting RSS image blur that can be exceeded by 10% of the field of view in the third quartile (0.80 arcsec FWHM) atmospheric seeing conditions.
0.52
ArcsecFWHM
10%outlierBudget_0.80


2.1.7 Stray and Scattered Light  
id:    
Version:  1.0 Modified:  2/17/2010 Status:  Proposed

The LSST design shall control the effects of stray and scattered light to the extent necessary to meet the performance in the Survey Specifications.
 
Discussion: Stray and scattered light is defined as any light that is not part of the ideal image and includes:
·   diffuse scattered light,
·   secondary ghost images,
·   diffraction,
·   structured glints.
 

 

2.1.7.1 Anti-Reflection Coatings  
id:    
Version:  1.0 Modified:  2/1/2010 Status:  Proposed

Specification: All refractive elements in the LSST optical system shall use state-of-the-art anti-reflection coatings to minimize the surface intensity of secondary ghost images and, at the same time, maximizing system throughput.

 

2.1.7.2 Baffling  
id:    
Version:  1.0 Modified:  2/1/2010 Status:  Proposed

Specification: The LSST optical system shall be baffled such that no unwanted specular path can put light onto the LSST focal plane.

 


2.1.8 Science Instrument  
id:    
Version:  1.0 Modified:  2/10/2010 Status:  Proposed

Specification: The LSST system shall contain a single science instrument - the Camera.
 
Specification: The LSST system shall be capable of using any one of 5 filters of the 6 specified for the survey during the course of a single night's operation.
 
Discussion: By the very nature of conducting a consistent well calibrated survey the LSST will not need to support multiple instruments often found on classical telescope systems.

 


2.2 Data Collection  
id:    
Version:  1.0 Modified:  2/4/2010 Status:  Proposed

Specification: The LSST shall provide a Data Collection system that is capable of providing all necessary data to meet the SRD survey specifications including science image data and all ancillary data need to calibrate the survey and to optimize operations.
 

 


2.2.1 Science Data  
id:    
Version:  1.0 Modified:  2/10/2010 Status:  Proposed

Specification: The LSST survey data shall be collected in the form of pixel addressable digital images that preserve the full information content of the LSST instrument.

 

2.2.1.1 Standard Visit  
id:    
Version:  1.0 Modified:  2/11/2010 Status:  Proposed

Specification: The standard "Visit" used to conduct the survey shall be defined as nVisitexp back to back exposures each having an exposure time of visitExpTime in one of the system spectral bands.

 
Description
Value
Unit
Attribute
The number of exposures in a standard visit shall be
2
 
nVisitExp
The exposure time for single images in a standard visit shall be
15
Seconds
visitExpTime

2.2.1.2 Time Interval Between Visits  
id:    
Version:  1.0 Modified:  2/11/2010 Status:  Proposed

Specification: The median time between successive visits shall be less than medianVisitInterval over the full set of survey observations.
 
Specification: The average time between successive visits shall be less than aveVisitInterval over the full set of survey observations
 
Discussion: This requirement is derived from the total number of visits per field and the total number of fields needed to cover the defined survey area. The interval between successive visits starts when the shutter of the second exposure of the visit is fully closed, and ends when the shutter of the first exposure of the next visit opens.

 
Description
Value
Unit
Attribute
The median interval as defined above over all successive vist pairs over the 10 year survey.
5
Seconds
medianVisitInterval
The average interval as defined above over all successive vist pairs over the 10 year survey
10
Seconds
aveVisitInterval

2.2.1.3 System Throughput  
id:    
Version:  1.0 Modified:  2/10/2010 Status:  Proposed

Specification: The LSST system throughput shall allow efficient collection of the science data over a wide range of wavelengths, from near the atmospheric cutoff in the blue to the band gap of silicon in the red.

 

2.2.1.3.1 Average System Response  
id:    
Version:  1.0 Modified:  2/11/2010 Status:  Proposed

Specification: The average system response efficiency through in each filter measured between their respective upper and lower wavelength limits shall be at least:
 
1.   u-band = uThroughputAve
2.   g-band = gThroughputAve
3.   r-band = rThroughputAve
4.   i-band = iThroughputAve
5.   z-band = zThroughputAve
6.   y-band = yThroughputAve
 
Discussion: The system response includes the efficiency of photon detection, lens and mirror coating performances, and the transmission of the atmosphere referenced at zenith under nominal conditions found at the Cerro Pachon site.

 

2.2.1.3.1.1 aveSystemThroughput  
isEncapsulated:    
Version:  1.0 Modified:  2/8/2010 Status:  Proposed

 
Description
Value
Unit
Attribute
The lower wavelength limit for the system u-band response shall be
320
nm
uLambdaLower
The upper wavelength limit for the system u-band response shall be
420
nm
uLambdaUpper
The average system response efficiency measured between the upper (uLambdaUpper) and lower (uLambdaLower) u-band limits shall be at least
15
Percent
uThroughputAve
The lower wavelength limit for the system g-band response shall be
380
nm
gLambdaLower
The upper wavelength limit for the system g-band response shall be
570
nm
gLambdaUpper
The average system response efficiency measured between the upper (gLambdaUpper) and lower (gLambdaLower) g-band limits shall be at least
50
Percent
gThroughputAve
The lower wavelength limit for the system r-band response shall be
515
nm
rLambdaLower
The upper wavelength limit for the system r-band response shall be
715
nm
rLambdaUpper
The average system response efficiency measured between the upper (rLambdaUpper) and lower (rLambdaLower) r-band limits shall be at least
70
Percent
rThroughputAve
The lower wavelength limit for the system i-band response shall be
645
nm
iLambdaLower
The lower wavelength limit for the system i-band response shall be
875
nm
iLambdaUpper
The average system response efficiency measured between the upper (iLambdaUpper) and lower (iLambdaLower) i-band limits shall be at least
70
Percent
iThroughputAve
The lower wavelength limit for the system z-band response shall be
760
nm
zLambdaLower
The upper wavelength limit for the system z-band response shall be
990
nm
zLambdaUpper
The average system response efficiency measured between the upper (zLambdaUpper) and lower (zLambdaLower) z-band limits shall be at least
60
Percent
zThroughputAve
The lower wavelength limit for the system y-band response shall be
945
nm
yLambdaLower
The upper wavelength limit for the system y-band response shall be
1100
nm
yLambdaUpper
The average system response efficiency measured between the upper (yLambdaUpper) and lower (yLambdaLower) y-band limits shall be at least
25
Percent
yThroughputAve

2.2.1.3.2 Throughput variation with time  
id:    
Version:  1.0 Modified:  2/8/2010 Status:  Proposed

Specification: TBD

 

2.2.1.3.3 Vignetting Function  
id:    
Version:  1.0 Modified:  2/15/2010 Status:  Proposed

Specification: The vignetting function shall vary smoothly over the field of view with a functional form corresponding to a polynomial with an order no more than vignettingFunc with an amplitude of no more than vignettingAmp.
 
Discussion: The amplitude of the vignetting is less than that alowed by the survey specifcation for image depth variation to allow for additional depth variation caused by variations in image quality allowed by the SRD.

 

2.2.1.3.3.1 vignettingFunction  
isEncapsulated:    
Version:  1.0 Modified:  2/15/2010 Status:  Proposed

 
Description
Value
Unit
Attribute
The amplitude of variation across the field of view.
15
Percent
vignetingAmp
The order of functional form for the vignetting pattern across the field of view.
3
 
vignettingFunc


2.2.2 Calibration Data  
id:    
Version:  1.0 Modified:  2/8/2010 Status:  Proposed

Specification: The LSST shall measure and record data relating to instrumental and atmospheric transmission needed to photometrically calibrate the science data referenced to the top of the Earth's atmosphere.

 


2.2.3 Engineering Data  
id:    
Version:  1.0 Modified:  2/8/2010 Status:  Proposed

Specification: The LSST Data collection system shall collect all engineering and environmental data necessary to capture the physical state of the observatory, its components, and surrounding environment, during all modes of operation.

 


2.2.4 Ancillary Data  
id:    
Version:  1.0 Modified:  2/8/2010 Status:  Proposed

Specification: The LSST system shall measure and record the needed data to provide the necessary inputs for optimizing the acquisition of survey data and a record of the environmental conditions that existed during each exposure. These data include:
 
1.   atmospheric seeing
2.   cloud cover
3.   meteorological information (temperatures, wind, humidity etc..)
 

 


2.3 Data Products & Processing  
id:    
Version:  1.0 Modified:  2/16/2010 Status:  Proposed

Specification: The data processing will calibrate the raw images, analyze them to generate source and object catalogs, detect and generate alerts for transient phenomena, and record the quality of the data collected and its processing provenance.
 

 


2.3.1 Calibrated Image Production  
id:    
Version:  1.0 Modified:  2/12/2010 Status:  Proposed

Specification: The LSST data processing system shall process raw image data to produce photometrically and astrometrically calibrated images.

 


2.3.2 Catalog Production  
id:    
Version:  1.0 Modified:  2/16/2010 Status:  Proposed

Specification: The data processing system shall process calibrated image data to produce catalogs of sources and objects.

 


2.3.3 Data Products  
id:    
Version:  1.0 Modified:  2/12/2010 Status:  Proposed

Specification: The LSST data processing system shall provide the means for organizing the production of three classes of data products: Level 1 (nightly cadence), Level 2 (data release cadence), and Level 3 (user-specified).

 

2.3.3.1 Level 1 Data Products  
id:    
Version:  1.0 Modified:  2/12/2010 Status:  Proposed

Specification: Level 1 Data Products are the result of processing of the stream of image data from the Data Collection system during normal observing.
 
Level 1 Data Products shall be produced and made publicly available within L1PublicT of the acquisition of the corresponding raw images, except for transient alerts which must meet the SRD latency requirement OTT1.

 

2.3.3.1.1 Data Quality Monitoring  
id:    
Version:  1.0 Modified:  2/16/2010 Status:  Proposed

Specification: Level 1 Data Product production shall include the production of sufficient Science Data Quality Assessment (SDQA) data, in a manner which supports feedback of observatory and observing conditions to the Observatory Control System, and alerts to observatory operators when poor quality data are detected.
 
SDQA data produced shall be archived in association with the corresponding raw image data.

 

2.3.3.2 Level 2 Data Products  
id:    
Version:  1.0 Modified:  2/12/2010 Status:  Proposed

Specification: Level 2 Data Products are the result of periodic processing of the entire archive of raw image data from the Data Collection system. The processing may additionally use as input other Level 1 Data Products corresponding to the raw images processed.
 
All Level 2 Data Products shall be produced in the context of Data Releases, within which a complete and consistent set of data products are generated.

 

2.3.3.2.1 Data Quality Monitoring  
id:    
Version:  1.0 Modified:  2/16/2010 Status:  Proposed

Specification: Level 2 Data Product production shall include the production of sufficient SDQA data to allow the determination of the scientific usability of the data products and the assessment of the large-scale progress of the survey.

 

2.3.3.2.2 Frequency of Data Releases  
id:    
Version:  1.0 Modified:  2/16/2010 Status:  Proposed

Specification: Data Releases of Level 2 Data Products shall be produced at intervals no less than the Survey Specification specification for standardized data release interval - DRT1.
 
Data Releases will be performed more frequently during the first year of the survey.
 

 

2.3.3.2.3 Scientific Content  
id:    
Version:  1.0 Modified:  2/12/2010 Status:  Proposed

Specification: The Level 2 Data Products in a Data Release shall include measurements of the properties (shapes, positions, fluxes, motions) of all detected objects, including those below the single-visit sensitivity limit, astrometric and photometric calibration of the object catalog, classification of objects based on their static properties and time-domain behavior, and deep coadded images of the full survey area on the sky.

 

2.3.3.3 Level 3 Data Products  
id:    
Version:  1.0 Modified:  2/16/2010 Status:  Proposed

Specification: Level 3 Data Products are the result of processing based on Level 1 and Level 2 Data Products, of a nature specified by users (by the provision of code and/or processing configuration data).
 
LSST data processing shall facilitate the efficient and convenient production of Level 3 Data Products, either using resources provided by the project or resources provided by the user that meet minimal specifications defined by the project.
 
Specification: The manner of production of Level 3 Data Products shall facilitate their federation with related Level 1 and Level 2 Data Products, when archived.
 
Discussion: The LSST project may promote selected Level 3 Data Products and their production to Level 2 or Level 1, subject to scientific justification and the availability of resources.

 

2.3.3.4 Calibrated Single Images  
id:    
Version:  1.0 Modified:  2/16/2010 Status:  Proposed

Specification: LSST data processing shall provide calibrated images from any past processing upon request.
 
Discussion: Calibrated image data must be available to retrieve, but may be reconstructed on demand as an alternative to its direct archiving.

 

2.3.3.5 Calibration Data Products  
id:    
Version:  1.0 Modified:  2/16/2010 Status:  Proposed

Specification: The data processing system shall, from time to time, generate Calibration Data Products, including bias frames and flat fields, as required by the other processing functions. These will typically appear at time scales intermediate to those of the Level 1 and Level 2 Data Products.

 

2.3.3.6 Science Database  
Version:  1.0 Modified:  2/16/2010 Status:  Proposed

Is the metadata in the Science Database (particularly the EFD subset and the processing provenance) technically considered part of the Level 2 Data products?

 


2.3.4 Optical Transient Alert Generation  
Id: DM-APP-DP-GR-11  
Version:  1.0 Modified:  2/16/2010 Status:  Proposed

Specification: The LSST data processing system shall detect optical transients in acquired raw images, record their detection and associated parameters, and make alerts available to external consumers.
 
 
Specification: The data processing shall differentiate between cosmic rays, moving objects and other optical transients.
 

 

2.3.4.1 Alert Generation Latency  
id:    
Version:  1.0 Modified:  2/16/2010 Status:  Proposed

Specification: Optical transient alerts shall be produced and transmitted to the distribution network for external users within the Survey Specifications for latency - OTT1.

 

2.3.4.2 Alert Generation Reliability  
id:    
Version:  1.0 Modified:  2/12/2010 Status:  Proposed

Specification: Alerts shall be transmitted within the specified latency for at least OTR1 (98%, TBC) of instances where the image data contains a transient detectable by the chosen science algorithm(s). The remaining detectable transients must still be identified and recorded at the next processing opportunity.

 


2.4 Data Archiving & Services  
id:    
Version:  1.0 Modified:  2/12/2010 Status:  Proposed

Specification: The LSST shall archive all image, catalog, engineering, calibration, and environmental data collected during the course of the survey, and shall make this data available for analysis and distribution.

 


2.4.1 Raw Image Data Archiving  
id:    
Version:  1.0 Modified:  2/12/2010 Status:  Proposed

Specification: The LSST system shall archive all raw science and calibration image data, as well as all wavefront sensor data. It shall also permit the archiving of such diagnostic image data as may be needed to support the commissioning and maintenance of the observatory.
 
Specification: The LSST system shall archive sufficient information to permit the reliable and reproducible retrieval of calibrated image data.
 
Discussion: Calibrated image data must be available to retrieve, but may be reconstructed on demand as an alternative to its direct archiving.

 


2.4.2 Data Product Archiving  
id:    
Version:  1.0 Modified:  2/12/2010 Status:  Proposed

Specification: The LSST system shall archive all Level 1, Level 2, and Calibration Data Products.

 


2.4.3 Engineering and Environmental Data Archiving  
id:    
Version:  1.0 Modified:  2/12/2010 Status:  Proposed

Specification: The LSST system shall archive all engineering and environmental data collected by the observatory.

 


2.4.4 Data Product Open Access  
Id: DM-APP-DP-LT-1  
Version:  1.0 Modified:  2/12/2010 Status:  Proposed

Specification: The LSST shall provide open access to Level 1 and Level 2 Data Products for the United States and observatory host nation scientific communities. This shall include access to all engineering, environmental, and ancillary data required for scientific interpretation of the Data Products.

 

2.4.4.1 Data Distribution  
id:    
Version:  1.0 Modified:  2/12/2010 Status:  Proposed

Specification: The LSST shall permit and facilitate the bulk distribution of its public data to remote sites wishing to consume or host it, subject to the availability of resources.
 
Discussion: This requirement is not intended to create an open-ended obligation to add bandwidth for data distribution. In cases where remote sites wish to host a large amount of LSST public data, it is anticipated that some cost-sharing arrangement may be needed to support the installation of additional data distribution capacity.

 

2.4.4.2 Data Product Access Interface  
id:    
Version:  1.0 Modified:  2/16/2010 Status:  Proposed

Specification: The LSST shall provide access to all its public data products through an interface that utilizes, to the maximum practicable extent, community-based standards such as those being developed by the Virtual Observatory (VO) community, and that facilitates user data analysis and the production of Level 3 and other user-defined data products at LSST-provided facilities and at remote sites.

 


2.4.5 Community computing services  
id:    
Version:  1.0 Modified:  2/16/2010 Status:  Proposed

Specification: The LSST shall provide and maintain an amount of computing cpacity equivalent to at least 10% of the total LSST data processing capacity to external users for the purpose of scientific analysis of LSST data.
 
Discussion: The scope of this service is to be determined based on a representative set of system queries and analyses assembled from community input.
 

 


3 Survey Operation & Administration  
id:    
Version:  1.0 Modified:  2/18/2010 Status:  Proposed

Specification: The Observatory shall be designed and developed to efficiently manage the execution of the survey.
 
Discussion: The LSST Observatory will be a comprehensive project to capture, process, archive, and serve data.

 


3.1 Operational Safety  
id:    
Version:  1.0 Modified:  2/18/2010 Status:  Proposed

Specification: The LSST shall be designed, constructed, and operated so that the safety of personnel, followed by safety of equipment, and then the prevention of data loss are preserved.
 
Discussion: The detailed sfety requirements and codes are documented in the Observatory System Specifications Document.

 


3.2 Public Data Release  
id:    
Version:  1.0 Modified:  2/16/2010 Status:  Proposed

Specification: The raw survey data and processed data products shall be made available to the public without any proprietary period.
 
Discussion: A necessary step in releasing the data is to do SDQA on it. However, even data prior to Data Release SDQA is available, with caveats to the user.

 


3.2.1 Data Quality Metrics  
id:    
Version:  1.0 Modified:  2/15/2010 Status:  Proposed

Specification: The Observatory shall include the necessary infrastructure and quality assessment capabilities to serve the defined data with the defined quality metrics.

 


3.3 Science Priorities & Survey Scheduling  
id:    
Version:  1.0 Modified:  2/15/2010 Status:  Proposed

Specification: The Observatory shall include a dynamic scheduler sufficient to achieve the survey requirements in the presence of changing observing conditions, nightly technical performance, and previous survey performance. The scheduler shall also have the following characteristics:

 


3.3.1 Scientific Priority  
id:    
Version:  1.0 Modified:  2/15/2010 Status:  Proposed

Specification: The reference survey can be accomplished in many observing sequences that impact the scientific reach of the accumulated data. The scheduler shall provide the ability to assign additional performance metrics that exploit the technical capacity of the LSST system to optimize the image by image sequence of observation.

 


3.3.2 Adjustment of Survey Priorities  
id:    
Version:  1.0 Modified:  2/16/2010 Status:  Proposed

Specification: The LSST shall allow for bi-annual adjustment of the scheduler's survey priorities based on community input.

 


3.3.3 Survey Performance Reviews  
id:    
Version:  1.0 Modified:  2/15/2010 Status:  Proposed

Specification: LSST shall have the ability to provide periodic status of the survey to allow operations staff and the community alike, to assess the survey progress.

 


3.3.4 Survey Simulation  
id:    
Version:  1.0 Modified:  2/15/2010 Status:  Proposed

Specification: The Observatory shall include the survey simulation tools to predict the results of the 10 year survey based on the actual survey completed to data as well as changes to the scientific priorities established in REQ-#### above. This tool set shall support planning of the survey at time scales of nightly, yearly, and the entire 10 year duration.

 


3.4 Observatory Control  
id:    
Version:  1.0 Modified:  2/15/2010 Status:  Proposed

Specification: The observatory shall be developed with the control centers to achieve the LSST objectives. This shall include, as a minimum, the capabilities defined here.

 


3.4.1 Central Administration  
id:    
Version:  1.0 Modified:  2/15/2010 Status:  Proposed

Specification: A central location shall serve as Project Headquarters for operational coordination and project interface.
 
Discussion: The LSST Observatory will be a distributed set of assets functioning for the specific objectives of executing the survey, serving the raw data and its data products to the public without any proprietary period. This will be a 24 hour per day operation that willl be capable of being administered and monitored from a single central location.

 


3.4.2 Process Command and Control  
id:    
Version:  1.0 Modified:  2/18/2010 Status:  Proposed

Specification: In addition to the connectivity required for the science data, the observatory shall include the necessary capability to command and control the process from discrete centers and to adjust for changing environmental, technical, and scientific conditions.

 


3.4.3 Local Administration  
id:    
Version:  1.0 Modified:  2/15/2010 Status:  Proposed

Specification: Each site in the LSST Observatory shall be capable of local autonomous control and operation. The system shall include the necessary provisions to function effectively when connections to other sites of the Observatory are interrupted.

 


3.4.4 Scientific & Technical Process Monitoring  
id:    
Version:  1.0 Modified:  2/18/2010 Status:  Proposed

Specification: The LSST project shall monitor the scientific and technical progress of the survey, communicate with the scientific user community and establish survey priorities, and adjust the survey design as needed to accomplish its goals given these priorities and achieved performance.
 

 


3.4.5 Scientific Oversight During Data Collection  
id:    
Version:  1.0 Modified:  2/16/2010 Status:  Proposed

Specification: The LSST Observatory shall be developed to allow an observing scientist to have oversight of the Data Collection process. This interaction shall be enabled either locally on the summit or at remote locations. The data provided shall include all observing condition data, telemetry data to assess telescope conditions, and data quality metrics for evaluation of the data collection process. The objective is to have the observing scientist to be directly involved in the observing process.

 


3.4.6 Autonomous Operation  
id:    
Version:  1.0 Modified:  2/15/2010 Status:  Proposed

Specification: The LSST system shall operate in a locally supervised autonomous mode during routine survey data collection and processing with little human intervention required.
 
Discussion: It is not practical to expect human driven observations to keep pace of observing cadence dictated by the LSST survey requirements.

 


3.5 Overall Operational Efficiency  
id:    
Version:  1.0 Modified:  2/18/2010 Status:  Proposed

Specification: The LSST system shall meet the Section 1 Survey Specifications for number of visits and area coverage including the constraints of weather, system dynamics, scheduled maintenance, and unscheduled down time.
 
Discussion: The specifications for the allowed allocations to each of the terms for non-observable time is contained in the companion document the Observatory Specifications.

 


3.5.1 Graceful Degradation  
id:    
Version:  1.0 Modified:  2/18/2010 Status:  Proposed

Specification: The LSST system will be designed so that its performance degrades gracefully in the presence of adverse environmental and/or operating conditions.
 

 


3.5.2 Survey Time Allocation  
id:    
Version:  1.0 Modified:  2/15/2010 Status:  Proposed

Specification: Approximately 90% of the LSST's available observing time shall be dedicated to a community defined common survey. The remaining available time will be available for special programs (e.g. targeted deep supernova programs).

 


3.5.3 System Operational Lifetime  
id:    
Version:  1.0 Modified:  2/15/2010 Status:  Proposed

Specification: The LSST system shall meet all its requirements and specifications for the duration of the 10 year survey.

 


3.5.4 Preventive Maintenance  
id:    
Version:  1.0 Modified:  2/15/2010 Status:  Proposed

Specification: The LSST system shall meet all its requirements and specifications for the duration of the 10 year survey by means of preventive maintenance, as opposed to replacement at failure.
 
Discussion: Preventive maintenance implies servicing, repairing, and replacing components and subsystems based on their expected lifetime, as opposed to their failure.

 


3.6 Education & Public Outreach  
id:    
Version:  1.0 Modified:  2/15/2010 Status:  Proposed

Specification: The LSST Observatory shall include an Education and Public outreach program that supports Federal "broader Impacts" requirements through education resources to interface with the LSST data in formal and informal education settings, Museums, and through common internet access.
 
Discussion: The National Science Foundation supports programs based on intellectual merit and broader impacts. The National Science Board strives for all America citizens to have the basic scientific, technological, and mathematical knowledge to make informed personal choices, to be educated voters, and to thrive in the increasingly technological global marketplace. The National Research Council, through its development of Science Education standards supports student learning and understanding of the natural world through inquiry.

 


3.7 Existing Infrastructure  
id:    
Version:  1.0 Modified:  2/15/2010 Status:  Proposed

Specification: The LSST Observatory shall utilize existing infrastructure, to the extent possible, and as available, to reduce the capital and operational costs. In particular, LSST shall evaluate the use of existing NSF funded astronomical sites, DOE Astrophysics Labs, and federally funded computer centers.
 

 

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