Table of Contents
Observatory System Specifications
1System Composition and Constraints
1.1Facilities
1.1.1The Summit Facility
1.1.2The Base Facility
1.1.3The Archive Facility
1.1.4The Headquarters Facility
1.2Sites
1.2.1Summit Site
1.2.1.1Summit Geographic Definitions
1.2.1.2Summit Environment
Normal Operating Conditions
Marginal Operating Conditions
Survival Conditions
Transportation/Shipping Environment
1.2.1.3Seismic Parameters for Design
1.2.1.4Astro-Climate
Atmospheric Seeing
Cloud Coverage
Standard Atmospheric Transmission
Standard Dark Sky Emission
Usable Observing Time
1.2.2Base Site
1.2.3Archive Site
1.2.4Headquarters Site
2Common System Functions & Performance
2.1Survey Scheduling and Management
2.1.1Survey Scheduling
2.1.1.1Environmental Optimization
2.1.1.2Multiple Science Programs
2.1.1.3Parallax Factor Sampling
2.1.1.4Scheduling Assessment
2.1.1.5Survey History Record
2.1.1.6Temporal Visit Distribution
2.1.1.7Visit Optimization
2.1.2Survey Planning and Performance Monitoring
2.2System Control
2.2.1Control Capabilities
2.2.1.1Local Autonomous Administration of System Sites
2.2.1.2Observatory Control System Definition
Scope of Control
Visit Sequencing
Manual Visit Specification
2.2.1.3Subsystem Activation
2.2.1.4Subsystem Health and Welfare
2.2.1.5Remote Operation Capabilities
2.2.2Standard Operating States
2.2.2.1Automated Survey Observing
2.2.2.2Calibration
2.2.2.3Engineering and Maintenance
2.2.2.4Manual Observing
2.2.3Degraded Operational States
2.2.3.1Summit Power Grid Loss
2.2.3.2Summit-Base Connectivity Loss
Summit Pixel Buffer
2.2.3.3Base-Archive Connectivity Loss
Base Data Buffer
Base Updating from Archive
2.3System Monitoring & Diagnostics
2.3.1Image Visualization
2.3.1.1Analytic Functions
2.3.1.2Display Timing Performance
2.3.1.3Image Data Sources
2.3.2Data Visualization
2.3.3Subsystem Telemetry
2.3.3.1Subsystem Metadata for Science Analysis
2.3.3.2Subsystem State Notification
2.3.3.3Subsystem Status
2.3.4Subsystem Baseline Performance Reporting
2.3.5Performance & Trend Analysis Toolkit
2.3.6Summit Environment Monitoring
2.3.6.1Atmospheric Seeing
2.3.6.2Atmospheric Turbulence Structure
2.3.6.3Cloud Mapping and Monitoring
2.3.6.4Weather and Meteorological Monitoring
2.3.6.5Seismic Monitoring
2.4System Maintenance
2.4.1Predictive Maintenance
2.4.2Preventive Maintenance
2.4.3Maintenance Activity Support
2.4.4Maintenance Reporting
2.4.5Maintenance Tracking and Analysis
2.5System Availability
2.5.1Scheduled Down Time
2.5.1.1plannedDownTime
2.5.2Unscheduled Down Time
2.5.3Event Recovery
2.5.3.1Frequent Earthquakes
2.5.3.2Infrequent Earthquakes
2.6System Time Reference
2.6.1Time Accuracy and Precision
2.6.2External Time Reporting Standard
2.6.3Internal Time Reporting Standard
2.7System Standards
2.7.1Environment
2.7.1.1Electromagnetic Emissions
2.7.1.2Night Light Emission
2.7.1.3Radio Active Background
2.7.2Building Codes
2.7.3Electrical and Controls Standards
2.7.4Minimum design Lifetime
2.7.5Safety
2.7.5.1Safety Priorities
2.7.5.2Hazard Analysis and Safety Practices
2.7.5.3Safety Plan
2.7.5.4Operational Safety Plan
2.7.5.5Emergency Communications
Earthquake Display
Summit Radio Equipment
2.7.6Health
2.7.7Security
2.7.7.1Cyber Security agency requirements
2.7.7.2Cyber Security best practices
3Detailed System Specifications
3.1Science and Bulk Data
3.1.1Science Image Handling Reliability
3.1.1.1Science Image Archiving Reliability
3.1.1.2Science Visit Alert Generation Reliability
3.1.2Data Acquisition
3.1.2.1Acquisition of Science Sensor data
3.1.3Data Processing
3.1.3.1General principles for data processing
Automated Production
Consistency and Completeness
Completeness
Consistency
Open Source, Open Configuration
Provenance
Reproducibility
Software Development Standards
3.1.4Data Products
3.1.4.1Level 1 Data Products
Level 1 Data Product Availability
Alerts
Exposures
Catalogs (Level 1)
Nightly Summary Products
Engineering and Facility Database Archive
3.1.4.2Level 2 Data Products
Level 2 Data Product Availability
Uniformly calibrated and processed versions of Level 1 Data Products
Co-added Exposures
Catalogs (Level 2)
Release Independence
3.1.4.3Level 3 Data Products
Production
Storage
Access
Resource Allocation
3.1.4.4Internal Data Products
Science Data Quality Analysis
WCS Reporting
3.1.4.5Data Quality
Instrument Signature Removal Quality
Catalog Accuracy
Difference Image Background
Image Characterization Quality
Photometric Zero Point Error
World Coordinate System Accuracy
World Coordinate System Contribution to Association Failures
Object Deblending
Coaddition Quality
Coaddition for Deep Detection
Coaddition for Templates for Subtraction
Moving Object Quality
Source-Object Association Quality
Deep Detection and Measurement Quality
Photometric Quality
Astrometric Quality
Catalog Completeness and Reliability
Transient Alert Quality
Alert Reliability
3.1.5Data Archiving
3.1.5.1Science Sensor Raw Data
3.1.5.2Data Products
3.1.5.3Calibration Data
3.1.5.4Engineering and Facilities Data
3.1.5.5Provenance Archiving
3.1.5.6Wavefront Sensor Raw Data
3.1.5.7Data Archive Lifetime
3.1.5.8Redundant Backup of Archive
3.1.6Data Access
3.1.6.1Data Access Environment
3.1.6.2Data Distribution
3.1.6.3Data Products Processing Infrastructure
3.1.6.4Data Products Query and Download Availability
3.1.6.5Data Products Query and Download Infrastructure
3.1.6.6Level 3 Data Product Access
3.1.6.7Transient Alerts
Transient Alert Publication
Transient Alert Query
3.1.6.8Access to Previous Data Releases
3.1.6.9Information Security
3.1.7Scoping
3.1.7.1Raw Exposures Per Night, Maximum
3.1.7.2Raw Exposures Per Year
3.1.7.3Galaxy Counts
3.1.7.4Star Counts
3.1.7.5Alerts per Visit
3.1.7.6Calibration Exposures Per Day
3.1.8Telemetry Data
3.1.8.1EFDB_OSSparameters
3.1.8.2Control Data
3.1.8.3Engineering Data
3.1.8.4Meta Data
3.1.8.5Monitoring Data
3.2Optical System
3.2.1Optical Design Specification
3.2.1.1M1 Prescription
3.2.1.2M2 Prescription
3.2.1.3M3 Prescription
3.2.1.4Mirror Spacings
3.2.1.5L1 Prescription
3.2.1.6L2 Presciption
3.2.1.7Filter Prescription
3.2.1.8L3 Prescription
3.2.1.9Lens Spacings
3.2.2Optical Alignment and Compensation
3.2.2.1Dynamic Alignment and Figure Compensation
Secondary (M2) Adjustement
Camera Adjustment
3.2.2.2One-time Static Compensation
L3+FPA to L2 Spacing
L3-FPA Spacing
3.2.2.3Wavefront Sensing Functions
Wavefront Estimation Range
Wavefront Sensing on Sky Efficiency
Wavefront Seonsor FPA Geometry
WFS Data Archiving and Buffering
3.2.3Ghost Image Control
3.2.3.1Lens Anti-Reflection Coating
3.2.4Stray and Scattered Light Control
3.2.4.1Lunar Stray Light
3.2.4.2Optical Baffing
3.2.5Image Quality
3.2.5.1System Image Quality
3.2.5.2Image Quality Subsystem Allocations
3.2.5.3Off Zenith Image Degradation
3.2.5.4Image Pixel Sampling
3.2.6Image Ellipticity
3.2.6.1Single Image PSF Ellipticity
3.2.6.210-year Ellipticity Residuals
3.3System Throughput
3.3.1Filter Response
3.3.1.1Filter Response Taper
3.3.1.2Filter Out of Band Constraints
3.3.1.3Filter Response Uniformity
3.3.1.4In-band Ripple
3.3.1.5u-band Response
3.3.1.6g-band Response
3.3.1.7r-band Response
3.3.1.8i-band Response
3.3.1.9z-band Response
3.3.1.10y-band Response
3.3.2Optical Throughput
3.3.2.1Total Optical Throughput
u-Band Throughput
g-band Throughput
r-band Throughput
i-band Throughput
z-band Throughput
y-band Throughput
3.3.2.2Telescope Throughput Allocation
3.3.2.3Camera Throughput Allocation
3.3.2.4Throughput variation
3.3.2.5Vignetting Function
3.3.310-year Integrated Throughput
3.3.3.1Focal Plane Coverage
3.3.3.2Focal Plane Losses
3.4Camera System
3.4.1Image Delivery
3.4.1.1Science Image Delivery
Raw Image Data
Cross-Talk Corrected Image Data
3.4.2Image Acquisition
3.4.2.1Science Data Bit Depth
pixelBitDepth
3.4.2.2Camera Pixel Noise
3.4.2.3Dynamic Range
3.4.2.4Filter Change
3.4.2.5Filter Swap
3.4.2.6Supported Image Types
3.4.3Imaging Control
3.5Photometric Calibration
3.5.1Calibration Data Processing
3.5.1.1Calibration and Image Processing
3.5.1.2Calibration Processing Performance Allocations
3.5.2Calibration of the Atmospheric Transmission
3.5.2.1Atmospheric Calibration Performance Allocations
3.5.2.2Atmospheric Transmission Sky Coverage
3.5.2.3Atmospheric Transmission Spectral Coverage
3.5.2.4Atmospheric Transmission Temporal Sampling
3.5.2.5Cloud Map
3.5.3Calibration of the Instrumental Transmission
3.5.3.1Instrument Calibration Performance Allocations
3.5.4Data Products for Photometric Calibration
3.5.4.1Reference Star Catalog
3.5.4.2White Dwarf Flux Standards
3.6System Timing and Dynamics
3.6.1Cadence and Visit Timing
3.6.1.1Standard Visit Duration
3.6.1.2Time Interval Between Visits
3.6.1.3Maximum time for shutter open/close transit
3.6.1.4Minimum Exposure Time
3.6.2Filter Swaps & Changes
3.6.2.1Maximum time for operational filter change
3.6.2.2Maximum time to swap internal filter
3.6.2.3Total Daytime Filter Changes
3.6.2.4Total Nighttime Filter Changes
3.6.3Observatory Pointing and Tracking
3.6.3.1Absolute Pointing
3.6.3.2Field de-rotation
Rotator Range
Rotator tracking Time
3.6.3.3Offset Pointing
3.6.3.4Open Loop Tracking
3.6.3.5Tracking Range
3.6.3.6Guiding
Guide Signal Source
Observatory System Specifications
Introduction and Scope
This Observatory System Specifications document describes the functional and performance requirements and allocations needed to fulfill the system functionality and survey performance described by the LSST System Requirements Document (LSE-29). These specifications include those derived from the following activities and/or modeling tools:
the reference system architecture consisting of 4 principle sites - summit, base, archive and headquarters
the selection of the summit site on Cerro Pachón;
the modeling the dynamic survey performance with the LSST Operations Simulator;
the optical design optimization;
the point source SNR analysis of the system throughput
In addition to the system specifications this document also includes required codes and regulations covering safety, construction, and other engineering standards.
Supporting Documents
- LSST Science Requirements Document (document LPM-17)
- LSST System Requirements (document LSE-29)
This document (LSE-30) is referenced to the Observatory System Specifications v1.1 baseline dated 2/22/2011 in the SysArch Enterprise Architect Database. The XML file of this baseline is LSE-53.
1System Composition and Constraints
The LSST system will consist of facilities constructed at several sites in Chile and the United States. In this section we enumerate the planned facilities and their functions. The data processing functions at these facilities are further divided into "Centers" -- collections of closely related activities.
We specify the choice of the physical sites used for the system design. These choices imply specific constraints that impact the system requirements and design. The specific sites derive system architecture and connectivity specifications. The choice, and the subsequent agreement with Chile, also determines particular requirements on the system that are provided.
The LSST site selection process resulted in the choice of Cerro Pachón in Chile for the location of the observatory itself. The weather and astro-climate (seeing and cloud cover) of Cerro Pachón provide system constraints under which the survey design requirements must be met which in turns drives certain system specifications.
1.1Facilities
ID: OSS-REQ-0001 / Last Modified: 9/16/2010The facilities that make up the LSST Observatory system are described below.
1.1.1The Summit Facility
ID: OSS-REQ-0002 / Last Modified: 12/1/2010Specification: The LSST shall provide a "Summit Facility" to host the following functions and their associated maintenance activities:
- Collection of the science data for the survey;
- Collection of additional data required for photometric calibration; and
- Control of the Observatory.
Discussion: The Summit Facility includes the main telescope and its enclosure, camera service areas, mirror coating systems, the auxiliary telescope and its enclosure, utility equipment, and all other infrastructure necessary to safely execute all the functions above and secure all LSST assets located on the summit. Summit Facility also must provide the space and functional equipment to safely maintain all the system assets operating on the site.
The normal operations of the observatory may also be controlled from the Base Facility, with the exception of actions for which safety and/or equipment protection considerations require operator presence on the summit. These restrictions will be documented in the LSST Safety Plan.
1.1.2The Base Facility
ID: OSS-REQ-0003 / Last Modified: 12/1/2010Specification: The LSST shall provide a "Base Facility" to host the following functions and their associated maintenance activities:
- The Primary Remote Observing facility to assist in the control of the Observatory;
- Survey planning and performance monitoring;
- Alert processing and data quality analysis for newly acquired science and calibration data;
- Collection of newly acquired data for transfer to the LSST data archive;
- Backup of the raw image and engineering data archives;
- Host Country Data Access Center, as defined below; and
- Control of Data Management operations (secondary location).
Discussion: The Base Facilitymay be a single structure or a series of co-located buildings that provides the personnel offices, computer equipment, and other specialized infrastructure necessary to safely execute all the functions above and to secure all LSST assets located at the Base.
1.1.3The Archive Facility
ID: OSS-REQ-0004 / Last Modified: 9/16/2010Specification: The LSST shall provide an "Archive Facility" to host the following functions:
- Ingest and daily reprocessing of all raw science data;
- Archiving of all data - raw, engineering, and derived products;
- Data Release production;
- United States Data Access Center; and
- Data Management Operations (secondary location).
Discussion: The Archive Facility includes the personnel offices, computer equipment, and other specialized infrastructure necessary to safely execute all the functions of the listed Centers and to secure all LSST assets located at the Archive.
1.1.4The Headquarters Facility
ID: OSS-REQ-0005 / Last Modified: 9/16/2010Specification: The LSST shall provide a "Headquarters Facility" to host the following functions:
- Survey planning and performance monitoring;
- Management of community science input;
- Overall Observatory and project administration;
- Education and Public Outreach; and
- Data Management Operations Center
Discussion: The function of Observatory and project administration includes the activities of a director, technical manager, business manager, and human resources, and covers all matters of compliance and reporting, interface to funding agencies, and management of the overall LSST Observatory and its operations world-wide.
The functions of Education and public outreach include the development of K-12 curricula, citizen science programs, and the necessary serving of LSST data to educators and the general public through a dedicated Data Access Center within, or in close proximity to, the Headquarters facility.
The Headquarters Facility includes the personnel offices, business equipment, and other specialized infrastructure necessary to safely execute all the functions above and to secure all LSST assets located at the Headquarters.
1.2Sites
ID: OSS-REQ-0006 / Last Modified: 9/15/2010Specification: The LSST Observatory system shall be designed to safely meet its technical requirements and operational specifications with the above-defined Facilities constructed at the following physical locations ("Sites"):
- Cerro Pachón in Chile for the Summit Facility;
- The AURA Recinto in La Serena, Chile for the Base Facility;
- The National Center for Supercomputing Applications (NCSA) in Urbana-Champaign, IL for the Archive Facility; and
- A continental U.S. site for the Headquarters Facility.
1.2.1Summit Site
ID: OSS-REQ-0007 / Last Modified: 12/1/2010Specification:The LSST observatory Summit Facility shall be located within the AURA property on Cerro Pachón (El Peñón), Chile, and shall meet all requirements for survey performance and operations at that site. All other functions of the Summit Facility shall be compatible with the defined weather, access, seismic and other site conditions provided below.
1.2.1.1Summit Geographic Definitions
ID: OSS-REQ-0008 / Last Modified: 8/28/2010Specifications: When design considerations require the specification of the summit site location, the following definitions for elevation, latitude, and longitude shall be used:
Description / Value / Unit / NameThe operational summit elevation to be used for design purposes is summitElevation. / 2650 / Meters / summitElevation
The operational site latitude to be used for design purposes is summit Latitude. / -30.2444 / Degrees / summitLatitude
The operational summit longitude to be used for design purposes is summitLongitude. / -70.7494 / Degrees / summitLongitude
1.2.1.2Summit Environment
ID: OSS-REQ-0009 / Last Modified: 12/1/2010Specification: All systems operating at the Summit Facility exposed to the external environment (includes the dome interior) shall meet all their functional and performance specifications for the Normal site conditions, shall operate in defined degraded modes under the Marginal conditions, and withstand without damage the non-operational Survival conditions provided below.
Normal Operating Conditions
ID: OSS-REQ-0010 / Last Modified: 12/1/2010Specification: The equipment and systems exposed to the external environment at the Summit Facilities shall meet all of their functional, performance, and operational specifications for the normal environmental conditions specified in the table below.
Discussion: These conditions correspond to the ~90% to 95% values of the weather distribution.
Description / Value / Unit / NameThe mean temperature for normal operations at the summit shall be normTempMean. / 11.5 / Celsius / normTempMean
The minimum temperature for normal operations at the summit shall be normTempMin. / -3.0 / Celsius / normTempMin
The maximum temperature for normal operations at the summit shall be normTempMax. / 19.0 / Celsius / normTempMax
The rate of change for design purposes shall be normTempGrad. / 0.7 / C/Hour / normTempGrad
When design considerations require operational wind specifications all summit based systems shall use the extreme operational wind speed, normWindMax. / 12 / m/sec / normWindMax
When design considerations require humidity specifications all summit based systems shall use the normal maximal operational relative humidity (non-condensing) normHumidityMax / 90 / Percent / normHumidityMax
When design considerations require humidity specifications all summit based systems shall use the normal mean operational relative humidity (non-condensing) normHumidityMean. / 40 / Percent / normHumidityMean
When design considerations require barometric pressure specifications all summit based systems shall use the mean pressure normBaroMean. / 749.3 / milibar / normBaroMean
Marginal Operating Conditions
ID: OSS-REQ-0011 / Last Modified: 12/1/2010Specification: The equipment and systems exposed to the external environment at the Summit Facilities shall be operable (not necessarily meeting all performance and functional requirements) over the range of marginal environmental conditions specified in the table below.
Discussion: These conditions correspond to the ~99% values of the weather distribution.
Description / Value / Unit / NameThe temperature rate of change for degraded operations is marginalTempGradient / 2.0 / C/Hour / marginaltempGradient
The maximum temperature for degraded operations at the summit shall be marginalTempMax. / 30 / Celsius / marginalTempMax
The minimum temperature for degraded operations at the summit shall be marginalTempMin. / -5 / Celsius / marginalTempMin
The maximum free air windspeed for degraded operations at the summit shall be marginalWind. / 20 / m/sec / marginalWind
Survival Conditions
ID: OSS-REQ-0012 / Last Modified: 12/1/2010Specification: The equipment and systems exposed to the external environment at the Summit Facilities shall the environmental conditions specified in the table below.
Description / Value / Unit / NameAll equipment on the summit must be capable of surviving a maximum humidity of survivalHumidity without damage. / 100 / Percent / survivalHumidity
The equipment in the interior of the summit facility must be capable of surviving a 10-second wind gust speed of survivalWindGust. / 25 / m/sec / survivalWindGust
The equipment in the interior of the summit facility must be capable of surviving a constant wind speed of survivalWind. / 20 / m/sec / survivalWind
The summit facilities and equipment permanently located on the exterior of the summit must be capable of surviving a constant wind speed of survivalWindExterior. / 54 / m/sec / survivalWindExterior
The survival load on the summit facilities due to snow shall be snowLoading (ref. Norma Chilena NCH 431). / 200 / kg/m^2 / snowLoading
The survival load on the summit facilities for ice on vertical surfaces shall be iceLoading (ref. Norma Chilena NCH 431) / 22 / kg/m^2 / iceLoading
All equipment located on the summit must be capable of surviving an ambient air temperature of survivalTemperature. / -10 / Celsius / survivalTemperature
Transportation/Shipping Environment
ID: OSS-REQ-0013 / Last Modified: 8/28/2010The shipping environment includes the general conditions when equipment is shipped to the summit. The equipment must remain undamaged after repeated shipments. Delivery is expected to be by plane or boat to Chile and then by road to the summit.
There is a tunnel on the road between the town of La Serena and the summit site on Cerro Pachon called the Puclaro Tunnel. Any equipment will have to pass through that tunnel. Its overall dimensions are given below.