1. Large Synoptic Survey Telescope (LSST)
  2. Camera Subsystem Requirements
  3. Pat Hascall
  4. LSE-59
  5. Latest Revision Date: February 1, 2016
  6. Change Record
    1. Table of Contents
  7. The LSST Camera Subsystem Requirements
    1. Introduction and Scope
    2. Definitions of Terms
    3. Supporting Documents
  8. The LSST Camera Subsystem Requirements
    1. 1 Camera Performance Allocations
      1. 1.1 Camera throughput
      2. 1.2 Crosstalk
      3. 1.3 Filter Response
      4. 1.4 Dynamic Range
      5. 1.5 Image bits per pixel
      6. 1.6 Camera max image quality error
      7. 1.7 Image Ellipticity
      8. 1.8 Camera lifetime
      9. 1.9 Total system read noise
      10. 1.10 Detector pixel pitch
      11. 1.11 Radioactive background
      12. 1.12 Electromagnetic Emissions
      13. 1.13 Electromagnetic Susceptibility
      14. 1.14 Light Emissions
      15. 1.15 Astrometric Requirements
    2. 2 Camera Optical Design
      1. 2.1 L1 Lens Prescription
      2. 2.2 L2 Lens Prescription
      3. 2.3 Filter Prescription
      4. 2.4 L3 Lens Prescription
      5. 2.5 Camera optics spacings
      6. 2.6 Detector plane+L3+Filter gap adjustability to L2
      7. 2.7 Detector plane-L3 gap adjustability
    3. 3 Camera Stray and Scattered Light
      1. 3.1 Lens Maximum Reflectance
      2. 3.2 Reflective surface treatments
      3. 3.3 Optical Baffling
    4. 4 Photometric Requirements
      1. 4.1 Camera optical throughput variation
      2. 4.2 Exposure duration accuracy
      3. 4.3 Exposure duration knowledge
      4. 4.4 Filter positioning for photometric precision
      5. 4.5 Throughput as-built knowledge
      6. 4.6 Long term gain stability
      7. 4.7 Short term gain stability
      8. 4.8 CCD temperature knowledge
    5. 5 Guiding
      1. 5.1 Guide Sensors
    6. 6 Wavefront Sensing
      1. 6.1 Wavefront Sensor Data
      2. 6.2 Wavefront Sensors
    7. 7 Camera operations
      1. 7.1 Camera command and telemetry
      2. 7.2 Exposure Control Operations
      3. 7.3 Science data read-out
      4. 7.4 Time Reference
      5. 7.5 Filter Operations
      6. 7.6 Camera Power-on
      7. 7.7 Camera Initialization
      8. 7.8 Camera Stand-alone Operations
      9. 7.9 Camera Engineering and Maintenance
      10. 7.10 Remote Operation Capabilities
      11. 7.11 Camera Scheduled Maintenance
      12. 7.12 Maintenance Recommendations
      13. 7.13 Camera Unscheduled Downtime
      14. 7.14 Number of shutter actuations
      15. 7.15 Safety System
      16. 7.16 Baseline Performance
      17. 7.17 Trend analysis
    8. 8 Camera Environmental Requirements
      1. 8.1 Normal Operations
      2. 8.2 Marginal Condition Operations
      3. 8.3 Survival Condition Operations
      4. 8.4 Transportation Condition Design
      5. 8.5 Design for Operable-Level Seismic Event
      6. 8.6 Design for Recoverable-Level Seismic Event
      7. 8.7 Design for Survival-Level Seismic Event
    9. 9 Standards
      1. 9.1 Components Standardization Goal
      2. 9.2 Plans and Standards
      3. 9.3 Safety

LSST Camera Subsystem Requirements
LSE-59
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The contents of this document are subject to configuration control and may not be changed, altered, or their provisions
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Large Synoptic Survey Telescope (LSST)

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Camera Subsystem Requirements

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Pat Hascall

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LSE-59

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Latest Revision Date: February 1, 2016
This LSST document has been approved as a Content-Controlled Document. Its contents are subject to
configuration control and may not be changed, altered, or their provisions waived without prior
approval. If this document is changed or superseded, the new document will retain the Handle
designation shown above. The control is on the most recent digital document with this Handle in the
LSST digital archive and not printed versions.

LSST Camera Subsystem Requirements
LSE-59
Latest Revision 2/1/2016
The contents of this document are subject to configuration control and may not be changed, altered, or their provisions
waived without prior approval.
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Change Record
Version
Date
Description
Owner name
1
5/8/2011
Initial Version
Patrick Hascall
1.1
5/9/2011
Added footer formatting
P. Hascall
1.2
7/12/2011
Draft version under camera team internal review
P. Hascall
1.3
7/29/2011
Edited to reflect camera team internal review
input; formatting changes
P. Hascall
2
7/17/2013
Incorporates changes from LCR-125 (approved
6/26/2013) and LCR-126 (approved 6/3/2013).
Also includes several grammatical/editorial
corrections.
P. Hascall and Brian
Selvy
3
10/7/2013
Incorporates camera throughput requirements
relaxation approved through LCR-133
P. Hascall
4
10/24/2014
Incorporates 18-bit Camera to DM interfaces,
barometric pressure data updates, revised OSS
timing requirements, exposure time updates in OSS
and LSR, revised filter definitions, omnibus OSS
updates, updated crosstalk requirements, addition
of an optics second surface clear aperture, removal
of exposure duration accuracy TBR, and update to
plans and standards approved via LCRs 131, 170,
176, 182, 183, 188, 189, 195, 213, and 214
P. Hascall and B. Selvy
5
6/2/2015
Incorporates approved LCRs 166, 233, 253.
Updated Camera requirement CAM-REQ-0071
Number of filter swap-outs - changed the
description in the constraint block FROM
"Maximum number of manual filter swaps per
month" TO "Minimum number of manual filter
swaps per month". This makes the constraint block
consistent with the requirement and also the
parent requirement (OSS-REQ-0320).
P. Hascall and B. Selvy
6
2/1/2016
Incorporates approved LCRs 480 and 490.
P. Hascall and B. Selvy

LSST Camera Subsystem Requirements
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waived without prior approval.
ii
Table of Contents
Change
Record
...............................................................................................................................................
i
Introduction
and
Scope
.................................................................................................................................
v
Definitions
of
Terms
......................................................................................................................................
v
Supporting
Documents
.................................................................................................................................
v
1
Camera Performance Allocations
........................................................................................... 1
1.1
Camera throughput
.............................................................................................................. 1
1.2
Crosstalk
.................................................................................................................................
3
1.3
Filter Response
..................................................................................................................... 4
1.4
Dynamic Range
................................................................................................................... 14
1.5
Image bits per pixel
............................................................................................................ 14
1.6
Camera max image quality error
.................................................................................... 15
1.7
Image Ellipticity
................................................................................................................... 15
1.8
Camera lifetime
................................................................................................................... 15
1.9
Total system read noise
................................................................................................... 15
1.10
Detector pixel pitch
......................................................................................................... 16
1.11
Radioactive background
............................................................................................... 16
1.12
Electromagnetic Emissions
.......................................................................................... 16
1.13
Electromagnetic Susceptibility
.................................................................................... 17
1.14
Light Emissions
............................................................................................................... 17
1.15
Astrometric Requirements
............................................................................................ 17
2
Camera Optical Design
............................................................................................................ 17
2.1
L1 Lens Prescription
......................................................................................................... 17
2.2
L2 Lens Prescription
......................................................................................................... 18
2.3
Filter Prescription
............................................................................................................... 18
2.4
L3 Lens Prescription
......................................................................................................... 20
2.5
Camera optics spacings
................................................................................................... 20

LSST Camera Subsystem Requirements
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iii
2.6
Detector plane+L3+Filter gap adjustability to L2
....................................................... 21
2.7
Detector plane-L3 gap adjustability
............................................................................... 21
3
Camera Stray and Scattered Light
....................................................................................... 21
3.1
Lens Maximum Reflectance
............................................................................................. 22
3.2
Reflective surface treatments
......................................................................................... 22
3.3
Optical Baffling
................................................................................................................... 22
4
Photometric Requirements
.................................................................................................... 22
4.1
Camera optical throughput variation
............................................................................ 22
4.2
Exposure duration accuracy
........................................................................................... 22
4.3
Exposure duration knowledge
........................................................................................ 23
4.4
Filter positioning for photometric precision
............................................................... 23
4.5
Throughput as-built knowledge
...................................................................................... 23
4.6
Long term gain stability
.................................................................................................... 24
4.7
Short term gain stability
................................................................................................... 24
4.8
CCD temperature knowledge
.......................................................................................... 24
5
Guiding
........................................................................................................................................
25
5.1
Guide Sensors
..................................................................................................................... 25
6
Wavefront Sensing
................................................................................................................... 25
6.1
Wavefront Sensor Data
..................................................................................................... 25
6.2
Wavefront Sensors
............................................................................................................. 25
7
Camera operations
................................................................................................................... 25
7.1
Camera command and telemetry
................................................................................... 25
7.2
Exposure Control Operations
......................................................................................... 26
7.3
Science data read-out
....................................................................................................... 27
7.4
Time Reference
................................................................................................................... 29
7.5
Filter Operations
................................................................................................................. 29
7.6
Camera Power-on
............................................................................................................... 31

LSST Camera Subsystem Requirements
LSE-59
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iv
7.7
Camera Initialization
.......................................................................................................... 31
7.8
Camera Stand-alone Operations
.................................................................................... 31
7.9
Camera Engineering and Maintenance
......................................................................... 31
7.10
Remote Operation Capabilities
.................................................................................... 32
7.11
Camera Scheduled Maintenance
................................................................................ 32
7.12
Maintenance Recommendations
................................................................................. 32
7.13
Camera Unscheduled Downtime
................................................................................. 32
7.14
Number of shutter actuations
...................................................................................... 32
7.15
Safety System
.................................................................................................................. 33
7.16
Baseline Performance
.................................................................................................... 33
7.17
Trend analysis
.................................................................................................................. 33
8
Camera Environmental Requirements
................................................................................ 33
8.1
Normal Operations
............................................................................................................. 33
8.2
Marginal Condition Operations
....................................................................................... 34
8.3
Survival Condition Operations
........................................................................................ 34
8.4
Transportation Condition Design
................................................................................... 35
8.5
Design for Operable-Level Seismic Event
................................................................... 35
8.6
Design for Recoverable-Level Seismic Event
............................................................ 36
8.7
Design for Survival-Level Seismic Event
..................................................................... 36
9
Standards
....................................................................................................................................
36
9.1
Components Standardization Goal
................................................................................ 36
9.2
Plans and Standards
......................................................................................................... 37
9.3
Safety
.....................................................................................................................................
37

LSST Camera Subsystem Requirements
LSE-59
Latest Revision 2/1/2016
The contents of this document are subject to configuration control and may not be changed, altered, or their provisions
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The LSST Camera Subsystem Requirements
Introduction and Scope
This document defines the imaging performance, data processing requirements and functional
requirements for the Camera portion of the LSST as allocated from the LSST Observatory System
Specifications (LSE-30). The requirements in this document, combined with those of the other LSST
subsystems satisfy the full functionality and performance for the LSST system.
Definitions of Terms
In this document a
requirement
refers to a declaration of a specified function or quantitative
performance that the delivered system or subsystem must meet. It is a statement that identifies a
necessary attribute, capability, characteristic, or quality of a system in order for the delivered system or
subsystem to meet a derived or higher requirement, constraint, or function.
This document uses the term
specification(s)
to mean one or more performance parameter(s) being
established by a requirement that the delivered system or subsystem must meet.
An
attribute
specifies a quantitative performance
parameter
in the context of the SysML based SysArch
model used to generate this document.
A
constraint
is used to refer to an external limitation imposed on a delivered item under which it must
meet its requirements (e.g., the survey performance must be met under the constraint of the historical
weather pattern of the chosen site). A constraint in not a characteristic the system or subsystem itself
possesses.
Supporting Documents
LSST Observatory System Specifications (LSE-30)

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The LSST Camera Subsystem Requirements
1 Camera Performance Allocations
1.1 Camera throughput
Last Modified: 6/9/2010
Discussion
: The total throughput is composed of several effects. One is the optical throughput which
addresses losses through the optics and CCD responsivity. The second effect is the percentage of the
focal plane that is sensitive to light (fill factor and dead pixels). The third effect is the percentage of time
the camera is available (covered elsewhere as down time).
1.1.1
Camera optical throughput
ID: CAM-REQ-0001
Last Modified: 7/15/2013
Specification
: The 10-year mean camera optical throughput shall be as defined in the table below for
each filter bandpass, averaged over each filter passband between the 90% response points. (TBR)
Discussion
: The components of the optical throughput are the factors in the camera that will attenuate
the light (e.g., lenses, contamination, and coatings), the sensor QE, and the filter transmissivity. Note that
the optical throughput for each filter band is tightly coupled to the definition of that band. The TBR will be
removed when the wording of the specification is tuned to match the project approach for using the filter
bandwidth and shape versus throughput.
Description
Value
Unit
Name
U-band optical throughput
30.3
Percent
CameraThroughput-
u
G-band optical throughput
59.5
Percent
CameraThroughput-
g
R-band optical throughput
63.9
Percent
CameraThroughput-
r
I-band throughput
61
Percent
CameraThroughput-
i
Z-band optical throughput
48.5
Percent
CameraThroughput-
z
Y-band optical throughput
10.1
Percent
CameraThroughput-
y
1.1.2
Effective Area
Last Modified: 7/29/2011
Discussion
: This section defines the camera active area on the focal plane. This defines the required
area and density of the science pixels on the as designed CCDs. Pixels that do not meet spec are
included in the area and density calculations (the percent of dead pixels allowable is covered in CAM-
REQ-0005).

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The active area is defined in terms of the central area on the focal plane equivalent to a 3.5 degree field
of view. At the focal plane, the diameter of that circle is
areaDiameter
.
Description
Value
Unit
Name
Diameter of the 3.5 degree FOV at the focal plane
634.17
mm
areaDiameter
1.1.2.1
Detector Plane central fill factor
ID: CAM-REQ-0003
Last Modified: 7/29/2011
Specification
: The fraction of the area covered by science sensors in the central circle with a radius of
[areaDiameter]
shall be at least
[CentralFill]
Discussion:
The area covered by science sensors includes unresponsive areas on the CCDs and the
gaps between the CCDs.
Description
Value
Unit
Name
3.5 degree FOV fill factor
85
Percent
CentralFill
1.1.2.2
Detector plane fill factor
ID: CAM-REQ-0004
Last Modified: 7/29/2011
Specification
: The fill factor of nominally active pixels in the area covered by science grade imaging
devices shall be at least [
TotalFill
]
Discussion
: The allowed fraction of dead pixels is specified in a separate requirement
Description
Value
Unit
Name
Fill factor of active pixels in the area covered by science grade
imaging devices
90
Percent
TotalFill
1.1.3
Detector plane allowable dead pixels
ID: CAM-REQ-0005
Last Modified: 7/11/2013
Specification
: The maximum percent of pixels on the detector plane within the 634.17 mm diameter FOV
that do not meet their requirements at delivery shall be
[deliveredPixelLoss]
. The additional pixel loss
over and above the [
deliveredPixelLoss]
when averaged over the 10-year survey lifetime shall be no
more than [
agedPixelLoss].
Discussion
: This includes pixels in otherwise live detectors that do not meet spec, and includes dead
pixels, hot pixels, dead columns, and dead segments/amplifiers.
Description
Value
Unit
Name
The minimum fraction of unusable pixels (those that can not
be calibrated to meet the requirements in this document) at
the time of instrument delivery
2
Percent
deliveredPixelLoss

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Description
Value
Unit
Name
The additional allowed pixel loss over and above the
deliveredPixelLoss
when averaged over the 10-year survey
lifetime
2
Percent
agedPixelLoss
1.2 Crosstalk
1.2.1
Crosstalk within a raft
ID: CAM-REQ-0097
Last Modified: 4/15/2013
Specification
: The crosstalk between any two electronic channels within a raft shall not exceed
[withinRaftCrosstalk]
.
Description
Value
Unit
Name
Maximum crosstalk on a raft
0.002
fraction
withinRaftCrosstalk
1.2.2
Crosstalk between rafts
ID: CAM-REQ-0098
Last Modified: 6/4/2014
Specification
: The crosstalk between any two electronic channels on different rafts shall not exceed
[betweenRaftCrosstalk]
with a goal of
[betweenRaftCrosstalkGoal]
.
Discussion
: If this requirement is not met, it may occur that the crosstalk correction applied by the
Camera on behalf of DM is not able to meet the performance goal for Alert Production. This is tracked as
a DM risk, where the risk response may require the development of a crosstalk correction stage for Alert
Production, with an impact on the alert latency. It is also tracked in the Camera risk list, where the
response may include action to remediate the crosstalk itself, or the collection of additional laboratory or
other data characterizing the actual crosstalk, to enable its successful correction in DM.
Description
Value
Unit
Name
Between raft crosstalk
0.0001
fraction
betweenRaftCrossta
lk
Goal for crosstalk between rafts
2.5e-5
fraction
betweenRaftCrossta
lkGoal
1.2.3
Raft to Raft crosstalk count
ID: CAM-REQ-0099
Last Modified: 9/9/2014
Specification
: For a single camera science raft there shall be no more than
[maxCrosstalkCount]
amplifiers on other science rafts that each contribute crosstalk greater than
[betweenRaftCrosstalkLimit]
to any pixel on that single raft.
Discussion
: If this requirement is not met, it may occur that the crosstalk correction applied by the
Camera on behalf of DM is not able to meet the performance goal for Alert Production. This is tracked as
a DM risk, where the risk response may require the development of a crosstalk correction stage for Alert

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Production, with an impact on the alert latency. It is also tracked in the Camera risk list, where the
response may include action to remediate the crosstalk itself, or the collection of additional laboratory or
other data characterizing the actual crosstalk, to enable its successful correction in DM.
Description
Value
Unit
Name
Number of amplifiers contributing crosstalk
256
int
maxCrosstalkCount
Crosstalk value below which raft to raft crosstalk can be
ignored
1e-5
int
betweenRaftCrossta
lkLimit
1.2.4
Crosstalk stability
ID: CAM-REQ-0100
Last Modified: 6/4/2014
Specification
: The crosstalk from any pixel to any other pixel shall be stable to
[crosstalkStability]
of a
full scale pixel over a period of
[crosstalkStabilityDuration]
days or the camera shall provide algorithms
and telemetry to enable the reconstruction of the crosstalk to
[crosstalkStability]
of a full scale pixel at
any time during that period.
Discussion
: If this requirement is not met, it may occur that the crosstalk correction applied by the
Camera on behalf of DM is not able to meet the performance goal for Alert Production. This is tracked as
a DM risk, where the risk response may require the development of a crosstalk correction stage for Alert
Production, with an impact on the alert latency. It is also tracked in the Camera risk list, where the
response may include action to remediate the crosstalk itself, or the collection of additional laboratory or
other data characterizing the actual crosstalk, to enable its successful correction in DM.
Description
Value
Unit
Name
Crosstalk stability
1e-5
fraction
crosstalkStability
Interval over which the crosstalk stability requirement is
applicable
14
Days
crosstalkStabilityDur
ation
1.2.5
Crosstalk correction extent
ID: CAM-REQ-0101
Last Modified: 4/15/2013
Specification
: The camera shall be capable of applying crosstalk corrections for each raft using all of the
amplifiers within that raft.
1.3 Filter Response
ID: CAM-REQ-0109
Last Modified: 2/1/2016
Specification:
Evaluation of the filter response shall use the area weighted mean response function as
defined in Document-16295 using the r-band beam defined in LSE-11.
Discussion:
The following definitions apply to the filter response requirements below
1.
The "filter response" function of a given point on the filter substrate refers to the net wavelength
response integrated over the incident optical beam centered at that point that has been normalized to a
unity mean between the "in-band" wavelength limits as defined for each filter. The normalized response

LSST Camera Subsystem Requirements
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5
function can have values greater than unity by no more than maxFiltRipple due to response wiggles
within the in-band region.
2.
The area weighted mean response function (as defined in Document-16295) is used combine the
filter response functions for points on the filter substrate into an average response.
3.
The r-band beam footprints defined in LSE-11 have been designated the nominal beam footprints
for use in evaluating filter performance. That footprint definition includes the annulus and beam angles at
both surfaces of each filter. The r-band filter annulus is typically within a few percent of the filter annulus
for the other bands, The u-band second surface is 7% smaller. The incident angle of the beam varies
linearly from the outer edge of the annulus to the inner edge of the annulus.
1.3.1
Filter Out of Band Constraints
ID: CAM-REQ-0110
Last Modified: 9/18/2014
Specification:
Each of the 6 defined filters must block it’s out of band transmission according to the
specifications in the table below.
Discussion:
For leakage that occurs in the wavelength region beyond 1050 the response of 100 micron
thick silicon at -100 C can be multiplied against the filter response in the total integrated leak evaluation.
Description
Value
Unit
Name
Up to
fLeakException
of the 10nm intervals 1 FWHM from
the central wavelength (between 300nm and 1200nm) may be
greater than
fLeak_10nm
but no more than
fLeakMax.
5.0
Percent
fleakException
The maximum allowed leakage.
0.1
Percent
fleakMax
The integrated transmission over all wavelengths between
300-1200nm outside the wavelength span between the first
time the filter response goes below 0.1% of the peak the total
leakage shall not exceeded
fleakTotal
relative to the total
integrated transmission between 300nm and 1200nm.
0.03
Percent
fLeakTotal
The average leakage in any 10nm segment between 300-
1200nm outside the wavelength span one FWHM from the
central wavelength shall be no more than
fLeak_10nm.
0.01
Percent
fLeak_10nm
1.3.2
Filter Response Uniformity
ID: CAM-REQ-0008
Last Modified: 1/28/2016
Specification:
The wavelength of the blue and red 50% response points of the response function at any
given point within the filter clear aperture shall not deviate by no more than
grizy_filtUniformity
and
u_filtUniformity
from that of the area weighted mean response function.
Description
Value
Unit
Name
The maximum allowed grizy-band filter response uniformity.
1.5%
Percent filtUniformity_grizy
The maximum allowed u-band filter response uniformity.
2.5%
Percent
filtUniformity_u

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6
1.3.3
In-band Ripple
ID: CAM-REQ-0009
Last Modified: 1/28/2016
Specification:
The in-band filter response function at any given point within the filter clear aperture shall
have peak-to-valley ripple of no more than +/-
maxFiltRipple
relative to the in-band mean for that
location.
Discussion:
The region for measuring ripple is defined by the in-band limits provided in the specifications
below. The in-band limits are allowed to be shifted by the measured shift allowed by CAM-REQ-0008.
Description
Value
Unit
Name
Allowed filter ripple
3
Percent
maxFiltRipple
1.3.4
u-band Response
ID: CAM-REQ-0010
Last Modified: 9/18/2014
Specification:
The area weighted mean u-band filter response normalized to the in-band average (as
measured between
u_inBandBlue
and
u_inBandRed
) shall lie between the upper and lower envelopes
defined in the tables below.
Description
Value
Unit
Name
The in-band blue limit for the u-band filter response
normalization.
335.5
nm
u_InBandBlue
The in-band red limit for the u-band filter response
normalization.
378.5
nm
u_InBandRed
Description
Value
Unit
Name
The blue side zero response wavelength of the u-band lower
envelope.
310.5
nm
u_lowerBlue(0)
The blue side 97% response wavelength of the u-band lower
envelope.
334.75
nm
u_lowerBlue(0.97)
The red side zero response wavelength of the u-band lower
envelope.
403.5
nm
u_lowerRed(0)
The red side 97% response wavelength of the u-band lower
envelope.
379.25
nm
u_lowerRed(0.97)
Description
Value
Unit
Name
The blue side zero response wavelength of the u-band upper
envelope.
305.5
nm
u_upperBlue(0)
The blue side 103% response wavelength of the u-band upper
envelope.
331.25
nm
u_upperBlue(1.03
)
The red side zero response wavelength of the u-band upper
envelope.
408.5
nm
u_upperRed(0)
The red side 103% response wavelength of the u-band upper
envelope.
382.75
nm
u_upperRed(1.03)

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1.3.4.1
u-band not to exceed envelope
ID: CAM-REQ-0113
Last Modified: 9/9/2014
Specification:
Over the wavelength range defined by the upper envelope - excluding the in-band range,
30% (by wavelength) of the area weighted average u-band filter response with may lie outside the
nominal upper and lower envelope, but shall lie completely within the minimum and maximum envelopes
defined below.
Discussion:
Specific instances of non compliance to this specification will be evaluated by the project to
assess acceptability.
Description
Value
Unit
Name
The blue side zero response wavelength of the u-band
minimum envelope.
313.5
nm
u_minBlue(0)
The blue side 97% response wavelength of the u-band
minimum envelope.
334.75
nm
u_minBlue(0.97)
The red side zero response wavelength of the u-band
minimum envelope.
400.5
nm
u_minRed(0)
The red side 97% response wavelength of the u-band
minimum envelope.
379.25
nm
u_minRed(0.97)
Description
Value
Unit
Name
The blue side zero response wavelength of the u-band
maximum envelope.
302.5
nm
u_maxBlue(0)
The blue side 103% response wavelength of the u-band
maximum envelope.
328.25
nm
u_maxBlue(1.03)
The red side zero response wavelength of the u-band
maximum envelope.
411.5
nm
u_maxRed(0)
The red side 103% response wavelength of the u-band
maximum envelope.
385.75
nm
u_maxRed(1.03)
1.3.5
g-band Response
ID: CAM-REQ-0011
Last Modified: 9/18/2014
Specification:
The area weighted mean g-band filter response normalized to the in-band average (as
measured between
g_inBandBlue
and
g_inBandRed
) shall lie between the upper and lower envelopes
defined in the tables below.
Description
Value
Unit
Name
The in-band blue limit for the g-band filter response
normalization.
416.5
nm
g_InBAndBlue
The in-band red limit for the g-band filter response
normalization.
537.0
nm
g_InBandRed

LSST Camera Subsystem Requirements
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waived without prior approval.
8
Description
Value
Unit
Name
The blue side zero response wavelength of the g-band lower
envelope.
391.5
nm
g_lowerBlue(0)
The blue side 0.97% response wavelength of the g-band
lower envelope.
415.75
nm
g_lowerBlue(0.97)
The red side zero response wavelength of the g-band lower
envelope.
562.0
nm
g_lowerRed(0)
The red side 0.97% response wavelength of the g-band lower
envelope.
537.75
nm
g_lowerRed(0.97)
Description
Value
Unit
Name
The blue side zero response wavelength of the g-band upper
envelope.
386.5
nm
g_upperBlue(0)
The blue side 103% response wavelength of the g-band upper
envelope.
412.25
nm
g_upperBlue(1.03
)
The red side zero response wavelength of the g-band upper
envelope.
567.0
nm
g_upperRed(0)
The red side 103% response wavelength of the g-band upper
envelope.
541.25
nm
g_upperRed(1.03)
1.3.5.1
g-band not to exceed envelope
ID: CAM-REQ-0114
Last Modified: 9/18/2014
Specification:
Over the wavelength range defined by the upper envelope - excluding the in-band range,
30% (by wavelength) of the area weighted average u-band filter response with may lie outside the
nominal upper and lower envelope, but shall lie completely within the minimum and maximum envelopes
defined below.
Discussion:
Specific instances of non compliance to this specification will be evaluated by the project to
assess acceptability.
Description
Value
Unit
Name
The blue side zero response wavelength of the g-band
minimum envelope.
394.5
nm
g_minBlue(0)
The blue side 97% response wavelength of the g-band
minimum envelope.
415.75
nm
g_minBlue(0.97)
The red side zero response wavelength of the g-band
minimum envelope.
559.0
nm
g_minRed(0)
The red side 97% response wavelength of the g-band
minimum envelope.
537.75
nm
g_minRed(0.97)
Description
Value
Unit
Name
The blue side zero response wavelength of the g-band
maximum envelope.
383.5
nm
g_maxBlue(0)
The blue side 103% response wavelength of the g-band
maximum envelope.
409.25
nm
g_maxBlue(1.03)
The red side zero response wavelength of the g-band
570.0
nm
g_maxRed(0)

LSST Camera Subsystem Requirements
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9
Description
Value
Unit
Name
maximum envelope.
The red side 103% response wavelength of the g-band
maximum envelope.
544.25
nm
g_maxRed(1.03)
1.3.6
r-band Response
ID: CAM-REQ-0012
Last Modified: 9/18/2014
Specification:
The area weighted mean r-band filter response normalized to the in-band average (as
measured between
r_inBandBlue
and
r_inBandRed
) shall lie between the upper and lower envelopes
defined in the tables below.
Description
Value
Unit
Name
The in-band blue limit for the r-band filter response
normalization.
567.0
nm
r_InBandBlue
The in-band red limit for the r-band filter response
normalization.
676.0
nm
r_InBandRed
Description
Value
Unit
Name
The blue side zero response wavelength of the r-band lower
envelope.
542.0
nm
r_lowerBlue(0)
The blue side 97% response wavelength of the r-band lower
envelope.
566.25
nm
r_lowerBlue(0.97)
The red side zero response wavelength of the r-band lower
envelope.
701.0
nm
r_lowerRed(0)
The red side 97% response wavelength of the r-band lower
envelope.
676.75
nm
r_lowerRed(0.97)
Description
Value
Unit
Name
The blue side zero response wavelength of the r-band upper
envelope.
537.0
nm
r_upperBlue(0)
The blue side 103% response wavelength of the r-band upper
envelope.
562.75
nm
r_upperBlue(1.03)
The red side zero response wavelength of the r-band upper
envelope.
706.0
nm
r_upperRed(0)
The red side 103% response wavelength of the r-band upper
envelope.
680.25
nm
r_upperRed(1.03)
1.3.6.1
r-band not to exceed envelope
ID: CAM-REQ-0115
Last Modified: 9/18/2014
Specification:
Over the wavelength range defined by the upper envelope - excluding the in-band range,
30% (by wavelength) of the area weighted average u-band filter response with may lie outside the
nominal upper and lower envelope, but shall lie completely within the minimum and maximum envelopes
defined below.

LSST Camera Subsystem Requirements
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10
Discussion:
Specific instances of non compliance to this specification will be evaluated by the project to
assess acceptability.
Description
Value
Unit
Name
The blue side zero response wavelength of the r-band
minimum envelope.
545.0
nm
r_minBlue(0)
The blue side 97% response wavelength of the r-band
minimum envelope.
566.25
nm
r_minBlue(0.97)
The red side zero response wavelength of the r-band
minimum envelope.
698.0
nm
r_minRed(0)
The red side 97% response wavelength of the r-band
minimum envelope.
676.75
nm
r_minRed(0.97)
Description
Value
Unit
Name
The blue side zero response wavelength of the r-band
maximum envelope.
534.0
nm
r_maxBlue(0)
The blue side 103% response wavelength of the r-band
maximum envelope.
559.75
nm
r_maxBlue(1.03)
The red side zero response wavelength of the r-band
maximum envelope.
709.0
nm
r_maxRed(0)
The red side 103% response wavelength of the r-band
maximum envelope.
683.25
nm
r_maxRed(1.03)
1.3.7
i-band Response
ID: CAM-REQ-0013
Last Modified: 9/18/2014
Specification:
The area weighted mean i-band filter response normalized to the in-band average (as
measured between
i_inBandBlue
and
i_inBandRed
) shall lie between the upper and lower envelopes
defined in the tables below.
Description
Value
Unit
Name
The in-band blue limit for the i-band filter response
normalization.
706.0
nm
i_InBandBlue
The in-band red limit for the i-band filter response
normalization.
803.0
nm
i_InBandRed
Description
Value
Unit
Name
The blue side zero response wavelength of the i-band lower
envelope.
681.0
nm
i_lowerBlue(0)
The blue side 97% response wavelength of the i-band lower
envelope.
705.25
nm
i_lowerBlue(0.97)
The red side zero response wavelength of the i-band lower
envelope.
828.0
nm
i_lowerRed(0)
The red side 97% response wavelength of the i-band lower
envelope.
803.75
nm
i_lowerRed(0.97)

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11
Description
Value
Unit
Name
The blue side zero response wavelength of the i-band upper
envelope.
676.0
nm
i_upperBlue(0)
The blue side 103% response wavelength of the i-band upper
envelope.
701.75
nm
i_upperBlue(1.03)
The red side zero response wavelength of the i-band upper
envelope.
833.0
nm
i_upperRed(0)
The red side 103% response wavelength of the i-band upper
envelope.
807.25
nm
i_upperRed(1.03)
1.3.7.1
i-band not to exceed envelope
ID: CAM-REQ-0116
Last Modified: 9/18/2014
Specification:
Over the wavelength range defined by the upper envelope - excluding the in-band range,
30% (by wavelength) of the area weighted average u-band filter response with may lie outside the
nominal upper and lower envelope, but shall lie completely within the minimum and maximum envelopes
defined below.
Discussion:
Specific instances of non compliance to this specification will be evaluated by the project to
assess acceptability.
Description
Value
Unit
Name
The blue side zero response wavelength of the i-band
minimum envelope.
684.0
nm
i_minBlue(0)
The blue side 97% response wavelength of the i-band
minimum envelope.
705.25
nm
i_minBlue(0.97)
The red side zero response wavelength of the i-band
minimum envelope.
825.0
nm
i_minRed(0)
The red side 97% response wavelength of the i-band
minimum envelope.
803.75
nm
i_minRed(0.97)
Description
Value
Unit
Name
The blue side zero response wavelength of the i-band
maximum envelope.
673.0
nm
i_maxBlue(0)
The blue side 103% response wavelength of the i-band
maximum envelope.
698.75
nm
i_maxBlue(1.03)
The red side zero response wavelength of the i-band
maximum envelope.
836.0
nm
i_maxRed(0)
The red side 103% response wavelength of the i-band
maximum envelope.
810.25
nm
i_maxRed(1.03)
1.3.8
z-band Response
ID: CAM-REQ-0014
Last Modified: 9/18/2014

LSST Camera Subsystem Requirements
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waived without prior approval.
12
Specification:
The area weighted mean z-band filter response normalized to the in-band average (as
measured between
z_inBandBlue
and
z_inBandRed
) shall lie between the upper and lower envelopes
defined in the tables below.
Description
Value
Unit
Name
The in-band blue limit for the z-band filter response
normalization.
833.0
nm
z_InBandBlue
The in-band red limit for the z-band filter response
normalization.
908.5
nm
z_InBandRed
Description
Value
Unit
Name
The blue side zero response wavelength of the z-band lower
envelope.
808.0
nm
z_lowerBlue(0)
The blue side 97% response wavelength of the z-band lower
envelope.
832.25
nm
z_lowerBlue(0.97)
The red side zero response wavelength of the z-band lower
envelope.
933.5
nm
z_lowerRed(0)
The red side 97% response wavelength of the z-band lower
envelope.
909.25
nm
z_lowerRed(0.97)
Description
Value
Unit
Name
The blue side zero response wavelength of the z-band upper
envelope.
803.0
nm
z_upperBlue(0)
The blue side 103% response wavelength of the z-band upper
envelope.
828.75
nm
z_upperBlue(1.03)
The red side zero response wavelength of the z-band upper
envelope.
938.5
nm
z_upperRed(0)
The red side 103% response wavelength of the z-band upper
envelope.
912.75
nm
z_upperRed(1.03)
1.3.8.1
z-band not to exceed envelope
ID: CAM-REQ-0117
Last Modified: 9/18/2014
Specification:
Over the wavelength range defined by the upper envelope - excluding the in-band range,
30% (by wavelength) of the area weighted average u-band filter response with may lie outside the
nominal upper and lower envelope, but shall lie completely within the minimum and maximum envelopes
defined below.
Discussion:
Specific instances of non compliance to this specification will be evaluated by the project to
assess acceptability.
Description
Value
Unit
Name
The blue side zero response wavelength of the z-band
minimum envelope.
811.0
nm
z_minBlue(0)
The blue side 97% response wavelength of the z-band
minimum envelope.
832.25
nm
z_minBlue(0.97)
The red side zero response wavelength of the z-band
minimum envelope.
930.5
nm
z_minred(0)

LSST Camera Subsystem Requirements
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13
Description
Value
Unit
Name
The red side 97% response wavelength of the z-band
minimum envelope.
909.25
nm
z_minred(0.97)
Description
Value
Unit
Name
The blue side zero response wavelength of the z-band
maximum envelope.
800.0
nm
z_maxBlue(0)
The blue side 103% response wavelength of the z-band
maximum envelope.
825.75
nm
z_maxBlue(1.03)
The red side zero response wavelength of the z-band
maximum envelope.
941.5
nm
z_maxRed(0)
The red side 103% response wavelength of the z-band
maximum envelope.
915.75
nm
z_maxRed(1.03)
1.3.9
y-band Response
ID: CAM-REQ-0015
Last Modified: 9/18/2014
Specification:
The area weighted mean y-band filter response normalized to the in-band average (as
measured between
y_inBandBlue
and
y_inBandRed
) shall lie between the upper and lower envelopes
defined in the tables below.
Description
Value
Unit
Name
The in-band blue limit for the y-band filter response
normalization.
938.5
nm
y_InBandBlue
The in-band red limit for the y-band filter response
normalization.
1069.25
nm
y_InBandRed
Description
Value
Unit
Name
The blue side zero response wavelength of the y-band lower
envelope.
913.5
nm
y_lowerBlue(0)
The blue side 97% response wavelength of the y-band lower
envelope.
937.75
nm
y_lowerBlue(0.97)
The red side zero response wavelength of the y-band lower
envelope.
1070.0
nm
y_lowerRed(0)
The red side 97% response wavelength of the y-band lower
envelope.
1070.0
nm
y_lowerRed(0.97)
Description
Value
Unit
Name
The blue side zero response wavelength of the y-band upper
envelope.
908.5
nm
y_upperBlue(0)
The blue side 103% response wavelength of the y-band upper
envelope.
934.25
nm
y_upperBlue(1.03)
The red side zero response wavelength of the y-band upper
envelope.
1201.0
nm
y_upperRed(0)
The red side 103% response wavelength of the y-band upper
envelope.
1201.0
nm
y_upperRed(1.03)

LSST Camera Subsystem Requirements
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The contents of this document are subject to configuration control and may not be changed, altered, or their provisions
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14
1.3.9.1
y-band not to exceed envelope
ID: CAM-REQ-0118
Last Modified: 9/18/2014
Specification:
Over the wavelength range defined by the upper envelope - excluding the in-band range,
30% (by wavelength) of the area weighted average u-band filter response with may lie outside the
nominal upper and lower envelope, but shall lie completely within the minimum and maximum envelopes
defined below.
Discussion:
Specific instances of non compliance to this specification will be evaluated by the project to
assess acceptability.
Description
Value
Unit
Name
The blue side zero response wavelength of the y-band
minimum envelope.
916.5
nm
y_minBlue(0)
The blue side 97% response wavelength of the y-band
minimum envelope.
937.75
nm
y_minBlue(0.97)
The red side zero response wavelength of the y-band
minimum envelope.
1070.0
nm
y_minRed(0)
The red side 97% response wavelength of the y-band
minimum envelope.
1070.0
nm
y_minRed(0.97)
Description
Value
Unit
Name
The blue side zero response wavelength of the y-band
maximum envelope.
905.5
nm
y_maxBlue(0)
The blue side 103% response wavelength of the y-band
maximum envelope.
931.25
nm
y_maxBlue(1.03)
The red side zero response wavelength of the y-band
maximum envelope.
1201.0
nm
y_maxRed(0)
The red side 103% response wavelength of the y-band
maximum envelope.
1201.0
nm
y_maxRed(1.03)
1.4 Dynamic Range
ID: CAM-REQ-0016
Last Modified: 7/11/2013
Specification:
The LSST Camera system shall have a single exposure unsaturated dynamic range of at
least
[camDynamicRange]
above the 5-sigma point source r-band limiting magnitude in a standard 15
second exposure.
Discussion:
This requirement is referenced to the fiducial conditions (defined in the LSR requirement
LSR-REQ-0089) used to define the limiting magnitude requirements.
Description
Value
Unit
Name
The camera minimum dynamic range in a single 15 second
exposure.
8
ABmag
camDynamicRange
1.5 Image bits per pixel

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15
ID: CAM-REQ-0017
Last Modified: 6/3/2014
Specification:
The imaging system shall acquire science data with a significance of
[campixelBitDepth]
bits per pixel.
Description
Value
Unit
Name
Bits per pixel
18
int
CamPixelBitDepth
1.6 Camera max image quality error
ID: CAM-REQ-0018
Last Modified: 7/11/2013
Specification
: The maximum delivered image quality error for the camera shall be less than
[
CameraImageQuality
] FWHM.
Discussion
: This is the total image quality error allocation to the camera, from all sources.
Description
Value
Unit
Name
Image quality error (FWHM)
0.30
ArcsecFW
HM
CameraImageQualit
y
1.7 Image Ellipticity
Last Modified: 6/2/2015
NOTE:
Ellipticity is a full-system requirement that, in principle, involves interactions among subsystems,
so it is not easily factorized. Therefore, LSST has chosen to manage the ellipticity requirement at the
observatory level, with the subsystems reporting the relevant performance best estimates to LSST
System Engineering, which updates the end-to-end ellipticity analysis and tracks the performance against
the requirement. This plan is documented in System Engineering Document-16234 (“LSST Integrated
Model for Image Performance Simulations”). Note that several Camera requirements (e.g., those related
to focal-plane flatness) that flow from the image quality requirement also support ellipticity performance.
1.8 Camera lifetime
ID: CAM-REQ-0019
Last Modified: 6/2/2015
Specification
: The camera and all subsystems and components shall be designed to operate for at least
[
CamLifetime
].
Discussion
: This includes the observatory lifetime plus additional time for camera integration, test, and
observatory commissioning.
Description
Value
Unit
Name
Camera lifetime
15
Years
CamLifetime
1.9 Total system read noise

LSST Camera Subsystem Requirements
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16
ID: CAM-REQ-0020
Last Modified: 4/15/2013
Specification:
The electronic noise from the LSST Camera system shall contribute no more than
camSysNoise
per exposure to each pixel in the data from the science sensor array.
Discussion:
This top level noise budget includes all sources internal to the camera system that
contribute to the base noise in each pixel, including readout noise, residual noise from dark current,
additional noise in the electronics, etc... The camera read noise requirement per exposure is derived from
the OSS requirement of 12.7e- per visit and the standard definition of two exposures per visit.
Description
Value
Unit
Name
Camera read noise per exposure
9
electrons
iCamReadNoise
1.10
Detector pixel pitch
ID: CAM-REQ-0021
Last Modified: 6/16/2011
Specification
: The detector nominal pixel pitch shall be [
PixelPitch
]
Discussion
: This corresponds to (0.2 arc-second) sampling
Description
Value
Unit
Name
Nominal pixel pitch
10
micron
PixelPitch
1.11
Radioactive background
ID: CAM-REQ-0022
Last Modified: 1/28/2015
Specification:
The Camera subsystem shall have a project-reviewed radioactive material test plan.
Discussion:
The Camera must develop a radioactive material test plan that defines testing approaches
that are reasonable such that the camera subsystem can achieve a radiation level that is "As Low as
Reasonably Achievable" (ALARA). The test plan must specify testing of critical components and
subsystems assemblies to ensure that their contributions are well below the level of artifacts caused by
cosmic radiation. Critical components and sub-assemblies, as well as test success criteria, will be
determined by the camera subsystem team taking into consideration the distance between the
components and sensors, shielding, component mass, and primary material of the component. A project-
reviewed radioactive material test plan means that the Camera subsystem test plan must be placed under
the Camera subsystem's change control; initial baselining and any subsequent updates must include
review and input from the LSST Project Systems Engineering (PSE) office.
1.12
Electromagnetic Emissions
ID: CAM-REQ-0023
Last Modified: 7/15/2013
Specification
: The camera shall not emit electromagnetic radiation that significantly interferes with itself
(as defined by meeting its performance specifications) or the operation of other observatory subsystems.
Off-the-shelf electronics devices shall be compliant with FCC part 15 Class B standards or shall have

LSST Camera Subsystem Requirements
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17
shielding or other mitigation. Custom designed camera electronics shall take advantage of all reasonable
good practices in design and fabrication to minimize interference.
1.13
Electromagnetic Susceptibility
ID: CAM-REQ-0024
Last Modified: 7/15/2013
Specification
:The camera shall not be susceptible to electromagnetic emissions from itself or other
elements in the observatory. Off-the-shelf electronics devices shall be compliant with FCC part 15 Class
A standards or shall have shielding or other mitigation. Custom designed camera electronics shall take
advantage of all reasonable good practices in design and fabrication to minimize susceptibility.
1.14
Light Emissions
ID: CAM-REQ-0025
Last Modified: 6/3/2011
Specification
: Light sources within the camera shall not escape out of the camera or cause camera
performance to go out of specification
1.15
Astrometric Requirements
Last Modified: 7/29/2011
Discussion
: There are no astrometric requirements on the camera. Modeling at the observatory level has
shown that astrometry can be realized by the existing algorithms without placing constraints on focal
plane stability
2 Camera Optical Design
Last Modified: 7/15/2011
Discussion:
The Camera optical prescription is a direct copy of the observatory prescription specified in
the Observatory System Spec (OSS).
The Camera optical prescription is given below with details and performance discussed in document LSE-
11. The prescription contains parameters to define each surface, their separations, and clear apertures.
All parameters follow the sign conventions used by the Zemax raytracing software.
https://www.lsstcorp.org/docushare/dsweb/Services/LSE-11
2.1 L1 Lens Prescription
ID: CAM-REQ-0026
Last Modified: 7/15/2013
Specification:
The prescription of the L1 lens shall be defined by the following table of parameters.
Discussion
: This prescription is a copy of the prescription called out in the Observatory System Spec
(OSS), and defines only nominal values; tolerances on figure and position are derived at a lower level

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18
from image quality requirements. These tolerances address impacts of gravity and other effects as the
camera pointing deviates from zenith.
Description
Value
Unit
Name
The radius of the first surface (s1) of the first lens (L1) shall be
[
L1-S1-Radius]
-2824.0
mm
L1-S1-Radius
The radius of the second surface (s2) of the first lens (L1)
shall be [
L1-S2-Radius].
-5021.00
mm
L1-S2-Radius
The center thickness of the first lens (L1) shall be
[L1CenThick]
82.23
mm
L1CenThick
The first lens (L1) shall be fabricated from
[L1GlassType]
Fused
Silica
L1GlassType
The first surface clear aperture diameter of the first lens (L1)
shall be at least [
L1S1OuterCA]
1550.00
mm
L1S1OuterCA
The second surface clear aperture diameter of the first lens
(L1) shall be at least [
L1S2OuterCA]
1523.00
mm
L1S2OuterCA
2.2 L2 Lens Prescription
ID: CAM-REQ-0027
Last Modified: 6/2/2015
Specification:
The prescription of the L2 lens shall be defined by the following table of parameters.
Discussion
: This prescription is a copy of the prescription called out in the Observatory System Spec
(OSS), and defines only nominal values; tolerances on figure and position are derived at a lower level
from image quality requirements. These tolerances address impacts of gravity and other effects as the
camera pointing deviates from zenith.
Description
Value
Unit
Name
The radius of the first surface (S1) of the second lens (L2)
shall be [
L2-S1-Radius]
Infinite
L2-S1-Radius
The second surface 6th order aspheric coefficient on the
second lens shall be [
L2-S2-6thAsphere].
1.656e-18
mm^-5
L2-S2-6thAsphere
The second surface (s2) conic constant on the second lens
(L2) shall be
[L2-S2Conic
].
-1.5700
L2-S2Conic
The radius of the second surface (s2) of the second lens (L2)
shall be
[L2-S2-Radius].
-2529.0
mm
L2-S2-Radius
The center thickness of the second lens (L2) shall be
[L2CenThick].
30.00
mm
L2CenThick
The second lens (L2) shall be fabricated from
[L2GlassType]
Fused
Silica
L2GlassType
The first surface clear aperture diameter of the second lens
(L2) shall be at least
[L2S1OuterCA].
1102.00
mm
L2S1OuterCA
The second surface clear aperture diameter of the second
lens (L2) shall be at least
[L2S2OuterCA].
1040.00
mm
L2S2OuterCA
2.3 Filter Prescription
ID: CAM-REQ-0028
Last Modified: 7/15/2013

LSST Camera Subsystem Requirements
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19
Specification:
The presciption of the filter substrates shall be defined by the following table of
parameters.
Discussion:
This prescription is a copy of the prescription called out in the Observatory System Spec
(OSS), and defines only nominal values; tolerances on figure and position are derived at a lower level
from image quality requirements. These tolerances address impacts of gravity and other effects as the
camera pointing deviates from zenith.
Description
Value
Unit
Name
The filter shall be fabricated from
filterGlassType
Fused
Silica
filterGlassType
The first surface clear aperture diameter of all filter substrates
shall be at least
filterS1OuterCa
756.00
mm
filterS1OuterCa
The radius of the first surface (s1) of the filter substrates shall
be
filter_s1Radius
-5632.0
mm
filter_s1Radius
The thicknes of the u-band filter substrate shall be
filterThick_u
26.60
mm
filterThick_u
The thicknes of the g-band filter substrate shall be
filterThick_g
21.50
mm
filterThick_g
The thicknes of the r-band filter substrate shall be
filterThick_r
17.90
mm
filterThick_r
The thicknes of the i-band filter substrate shall be
filterThick_i
15.70
mm
filterThick_i
The thicknes of the z-band filter substrate shall be
filterThick_z
14.4
mm
filterThick_z
The thicknes of the y-band filter substrate shall be
filterThick_y
13.60
mm
filterThick_y
The radius of the second surface (s2) of the u-band filter
substrate shall be
filter_s2Radius_u
-5530.0
mm
filter_s2Radius_u
The radius of the second surface (s2) of the g-band filter
substrate shall be
filter_s2Radius_g
-5576.0
mm
filter_s2Radius_g
The radius of the second surface (s2) of the r-band filter
substrate shall be
filter_s2Radius_r
-5606.0
mm
filter_s2Radius_r
The radius of the second surface (s2) of the i-band filter
substrate shall be
filter_s2Radius_i
-5623.0
mm
filter_s2Radius_i
The radius of the second surface (s2) of the z-band filter
substrate shall be
filter_s2Radius_z
-5632.0
mm
filter_s2Radius_z
The radius of the second surface (s2) of the y-band filter
substrate shall be
filter_s2Radius_y
-5640.0
mm
filter_s2Radius_y
The second surface clear aperture diameter the u-band filter
substrate shall be at least
filterS2OuterCa_u
737.00
mm
filterS2OuterCa_u
The second surface clear aperture diameter the g-band filter
substrate shall be at least
filter2OuterCa_g
741.00
mm
filterS2OuterCa_g
The second surface clear aperture diameter the r-band filter
substrate shall be at least
filterS2OuterCa_r
745.00
mm
filterS2OuterCa_r
The second surface clear aperture diameter the i-band filter
substrate shall be at least
filterS2OuterCa_i
746.00
mm
filterS2OuterCa_i
The second surface clear aperture diameter the z-band filter
substrate shall be at least
filterS2OuterCa_z
747.00
mm
filterS2OuterCa_z

LSST Camera Subsystem Requirements
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20
Description
Value
Unit
Name
The second surface clear aperture diameter the y-band filter
substrate shall be at least
filterS2OuterCa_y
748.00
mm
filterS2OuterCa_y
2.4 L3 Lens Prescription
ID: CAM-REQ-0029
Last Modified: 7/15/2013
Specification:
The prescription of the third lens (L3) shall be defined by the following table of
parameters.
Discussion
: This prescription is a copy of the prescription called out in the Observatory System Spec
(OSS), and defines only nominal values; tolerances on figure and position are derived at a lower level
from image quality requirements. These tolerances address impacts of gravity and other effects as the
camera pointing deviates from zenith.
Description
Value
Unit
Name
The first surface (s1) conic constant on the third lens (L3)
shall be
[L3-S1Conic]
.
-0.9620
L3-S1Conic
The radius of the first surface (s1) of the third lens (L3) shall
be [
L3-S1-Radius].
-3169.0
mm
L3-S1-Radius
The radius of the second surface (s2) of the third lens (L3)
shall be [
L3-S2-Radius].
13360.0
mm
L3-S2-Radius
The center thickness of the third lens (L3) shall be
[L3CenThick].
60.00
mm
L3CenThick
The third lens (L3) shall be fabricated from
[L3GlassType].
Fused
Silica
L3GlassType
The first surface clear aperture radius of the third lens (L3)
shall be at least
[L3S1OuterCA].
722.00
mm
L3S1OuterCA
The second surface clear aperture radius of the third lens (L3)
shall be at least
[L3S2OuterCA].
722.00
mm
L3S2OuterCA
2.5 Camera optics spacings
ID: CAM-REQ-0030
Last Modified: 7/15/2013
Specification
: The prescription for the separation of the Camera optical elements shall be defined by the
parameters in the table below.
Discussion:
This prescription is a copy of the prescription called out in the Observatory System Spec
(OSS), and defines only nominal values; tolerances on figure and position are derived at a lower level
from image quality requirements.
Description
Value
Unit
Name
The distance from the vertex of the second surface of L1 to
the vertex of the first surface of L2 shall be
l1_l2Spacing.
-412.642
mm
l1_l2Spacing
The distance from the vertex of the second surface of L2 to
the vertex of the first surface of the filter substrate shall be
L2_filterSpacing.
-349.58
mm
l2_filterSpacing

LSST Camera Subsystem Requirements
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21
Description
Value
Unit
Name
The distance from the vertex of the second surface of the u-
band filter substrate to the vertex of the first surface of L3
shall be
L3_filterSpacing_u.
-42.40
mm
l3_filterSpacing_u
The distance from the vertex of the second surface of the g-
band filter substrate to the vertex of the first surface of L3
shall be
L3_filterSpacing_g.
-47.50
mm
l3_filterSpacing_g
The distance from the vertex of the second surface of the r-
band filter substrate to the vertex of the first surface of L3
shall be
L3_filterSpacing_r.
-51.10
mm
l3_filterSpacing_r
The distance from the vertex of the second surface of the i-
band filter substrate to the vertex of the first surface of L3
shall be
L3_filterSpacing_i.
-53.30
mm
l3_filterSpacing_i
The distance from the vertex of the second surface of the z-
band filter substrate to the vertex of the first surface of L3
shall be
L3_filterSpacing_z.
-54.60
mm
l3_filterSpacing_z
The distance from the vertex of the second surface of the y-
band filter substrate to the vertex of the first surface of L3
shall be
L3_filterSpacing_y.
-55.40
mm
l3_filterSpacing_y
The distance from the vertex of the second surface of L3 to
the focal plane array (FPA) shall be
l3_fpaSpacing.
-28.50
mm
l3_fpaSpacing
2.6 Detector plane+L3+Filter gap adjustability to L2
ID: CAM-REQ-0031
Last Modified: 7/15/2011
Specification
: The detector plane + L3 + Filter shall be capable of being adjusted one time by +/-
[
DetL3FilterAdjust
] with respect to L2
Discussion
: This provides compensation for the as-built figure errors in the mirrors. This adjustment
essentially redefines the optical spacing defined in CAM-REQ-0030. Thus the tolerance of this adjustment
is controlled by the image quality budget.
Description
Value
Unit
Name
L2 to L3+filter+detector plane spacing adjustability
5
mm
DetL3FilterAdjust
2.7 Detector plane-L3 gap adjustability
ID: CAM-REQ-0032
Last Modified: 1/6/2011
Specification
: The gap between the detector plane and L3 shall be capable of being adjusted one time
by +/- [
Det-L3GapAdjust
]
Discussion
: This provides compensation for the as-built figure errors in the mirrors
Description
Value
Unit
Name
Detector plane to L3 spacing adjustability
3.5
mm
Det-L3GapAdjust
3 Camera Stray and Scattered Light

LSST Camera Subsystem Requirements
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22
3.1 Lens Maximum Reflectance
ID: CAM-REQ-0033
Last Modified: 1/28/2016
Specification:
The reflection at any location in the pupil for any field angle in the 3.5 degree field of view
on any transmissive optical surface (not including filters), shall be less than
lensReflection
at all
wavelengths between 300-1100nm using the r-band beam angles of incidence defined in LSE-11.
Discussion:
These specifications constrain the intensity of the 2-reflection ghost images.
The r-band beam defined in LSE-11 has been designated the nominal beam for use in evaluating the lens
reflections. That definition includes the beam angles at both surfaces of each lens.
Description
Value
Unit
Name
The maximum allowable reflection fraction from any lens
surface after AR coating.
2
Percent
lensReflection
3.2 Reflective surface treatments
ID: CAM-REQ-0034
Last Modified: 6/16/2011
Specification
: Reflective surfaces near the main beam shall either be shielded by light baffles, painted
flat black or treated/shaped to minimize scattering.
3.3 Optical Baffling
ID: CAM-REQ-0035
Last Modified: 4/13/2011
Specification
: The camera shall be baffled such that there are no direct specular paths to the focal plane
from celestial sources that are outside the nominal field of view
4 Photometric Requirements
4.1 Camera optical throughput variation
ID: CAM-REQ-0036
Last Modified: 4/27/2015
Specification:
When flowing down the throughput requirements to the component level, the Camera
shall set a single minimum quantum efficiency (QE) specification, for each filter band, that is to be met by
each science sensor in the focal plane, averaged over its active area.
Discussion:
This is understood to implement the throughput variation requirements in Table 7 of the
Science Requirements Document, LPM-17 and OSS-REQ-0256.
4.2 Exposure duration accuracy
ID: CAM-REQ-0037
Last Modified: 10/22/2014

LSST Camera Subsystem Requirements
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23
Specification
: The accuracy of the shutter exposure duration shall be <[
ExposureDurationAccuracy
].
Discussion
: The accuracy is the difference between the actual duration and what was requested.
Description
Value
Unit
Name
Exposure duration accuracy
50
m-sec
ExposureDurationA
ccuracy
4.3 Exposure duration knowledge
ID: CAM-REQ-0102
Last Modified: 7/8/2013
Specification
: The exposure duration shall be known to within [
ExposureDurationKnowledge
] of the
actual value for any position on the focal plane for the standard exposure of 15 seconds.
Description
Value
Unit
Name
Exposure duration knowledge
2
Percent
RMS
exposureDurationKn
owledge
4.4 Filter positioning for photometric precision
ID: CAM-REQ-0040
Last Modified: 4/20/2015
Specification
: The light impinging on a particular pixel passes through a circle approximately 100mm in
diameter on the surface of the filter. The knowledge of position of the center of that circle on a specific
filter for any pixel on the best fit detector plane between any two camera orientations shall be better than
[FilterPosKnowledge],
including effects of filter changes.
Discussion:
This requirement, coupled with the filter response uniformity requirement (CAM-REQ-0008)
satisfies the OSS requirement OSS-REQ-0331 per the analysis in LSE-180. This does not include
changes to the incoming light angles due to hexapod driven changes to camera position.
Description
Value
Unit
Name
Filter position knowledge
1.65
mm
FilterPosKnowledge
4.5 Throughput as-built knowledge
ID: CAM-REQ-0041
Last Modified: 7/8/2013
Specification
: The as-built camera throughput shall be measured separately from the telescope with
relative accuracy of
[ThroughputOverFOV]
over spatial scales of 1 degree on the focal plane
(approximately the size of a raft) for light at a fixed angle of incidence and in LSST griz bands. The
angular dependence of the throughput shall be measured over the range 14-26 degrees for at least one
point on the focal plane. (TBR)
Discussion
: This is to provide data for use in extraction of dome flat illumination corrections.

LSST Camera Subsystem Requirements
LSE-59
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24
Description
Value
Unit
Name
Throughput as built knowledge relative accuracy
0.25
Percent
ThroughputOverFO
V
4.6 Long term gain stability
ID: CAM-REQ-0104
Last Modified: 7/8/2013
Specification
: The video channel gain shall be stable to within [
12HourGainStability]
over a 12-hour
observing period. Alternatively appropriate algorithms and telemetry data shall be provided to enable
reconstruction of changes in video channel gain to within [
12HourGainStability]
over a 12-hour
observing period.
Description
Value
Unit
Name
Gain stability over 12 hours
1
Percent
RMS
12HourGainStability
4.7 Short term gain stability
ID: CAM-REQ-0105
Last Modified: 7/8/2013
Specification
: The video channel gain shall be stable to within [
1HourGainStability]
over a 1-hour
observing period. Alternatively appropriate algorithms and telemetry data shall be provided to enable
reconstruction of changes in video channel gain to within [
1HourGainStability]
over a 1-hour observing
period.
Description
Value
Unit
Name
Gain stability over 1 hour
0.1
Percent
RMS
1HourGainStability
4.8 CCD temperature knowledge
ID: CAM-REQ-0103
Last Modified: 7/8/2013
Specification
: The camera shall provide sufficient telemetry and models to enable reconstruction of the
temperature at any point on the active portion of the sensor surface to an accuracy of
[TempRelAccuracy]
Kelvin relative to the temperature at a reference time no more than
[TempRefInterval]
(TBR) in the past. The temperature measurements shall be accurate to within
[TempAbsAccuracy]
Kelvin on an absolute scale.
Discussion
: This requirement does not cover periods that span significant camera maintenance.
Description
Value
Unit
Name
Relative accuracy (precision)
0.5
Degrees
TempRelAccuracy
Time interval between reference narrowband calibration and
the time of the image for which the temperature is measured
30
Days
TempRefInterval
Absolute accuracy of the temperature measurement
5
Degrees
TempAbsAccuracy

LSST Camera Subsystem Requirements
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Latest Revision 2/1/2016
The contents of this document are subject to configuration control and may not be changed, altered, or their provisions
waived without prior approval.
25
5 Guiding
5.1 Guide Sensors
ID: CAM-REQ-0043
Last Modified: 7/11/2013
Specification
: The camera shall provide guide sensors to support telescope guiding.
Discussion
: The requirements for these guide sensors are in the Camera to Telescope Guiding ICD
(LSE-66).
6 Wavefront Sensing
6.1 Wavefront Sensor Data
ID: CAM-REQ-0044
Last Modified: 6/15/2011
Specification:
For the purposes of archiving and buffering the wavefront sensor imaging data shall be
treated the same as science image data.
6.2 Wavefront Sensors
ID: CAM-REQ-0045
Last Modified: 7/11/2013
Specification:
The camera shall provide 4 wavefront sensors located near the corners of the inscribed
square to the 3.5 degree FOV.
Discussion:
The wavefront sensor requirements are in the Camera to Telescope Wavefront Sensing ICD
(LSE-67).
7 Camera operations
7.1 Camera command and telemetry
7.1.1
Commanding from OCS
ID: CAM-REQ-0046
Last Modified: 7/11/2013
Specification
: The camera shall support commands from the OCS to power-up and initialize the camera,
to change filters and to take exposures.
Discussion:
The full list of commands is defined in the OCS to Camera ICD. (LSE-71).
7.1.2
Camera telemetry transfer method

LSST Camera Subsystem Requirements
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waived without prior approval.
26
ID: CAM-REQ-0047
Last Modified: 7/11/2013
Specification:
The camera shall publish telemetry using the Observatory specified protocol as defined in
the OCS Architecture and Protocol ICD (LSE-70).
7.1.3
Camera meta-data availability
ID: CAM-REQ-0048
Last Modified: 7/11/2013
Specification
: The camera telemetry shall include all required information (metadata) needed for the
scientific analysis of the survey data.
Discussion:
This includes metadata to maintain the required photometric precision and accuracy during
operations between daily and periodic calibration.
7.1.4
Camera State Notification
ID: CAM-REQ-0049
Last Modified: 6/16/2011
Specification:
The camera shall report any changes in its major internal state.
7.1.5
Camera Status
ID: CAM-REQ-0050
Last Modified: 6/15/2011
Specification:
The Camera shall assess and report an overall hardware health status for major camera
components.
Discussion:
The primary purpose of these status indicators is for the OCS to be able to orchestrate
normal operations and handle out of normal conditions.
7.2 Exposure Control Operations
7.2.1
Visit timing
ID: CAM-REQ-0051
Last Modified: 7/11/2013
Specification
: The camera shall complete each visit (not including the readout of the last exposure in the
visit) within
[CamVisitTiming].
Discussion
: The allocation covers two 15 second exposures plus shutter travel overhead for both
exposures and CCD readout for the first exposure. The CCD readout for the second exposure is not
included because the telescope can start to move to the next visit location while the camera is reading out
the second exposure.
Description
Value
Unit
Name

LSST Camera Subsystem Requirements
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Latest Revision 2/1/2016
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waived without prior approval.
27
Description
Value
Unit
Name
Visit duration, not counting readout of the second exposure
34
Seconds
CamVisitTiming
7.2.2
Bias/zero exposures
ID: CAM-REQ-0052
Last Modified: 1/6/2011
Specification
: The camera shall be able to perform bias/zero exposures.
Discussion
: These exposures are taken without any CCD integration time. Otherwise the CCDs are
prepared for an exposure as usual. At the time the shutter would normally open, the CCD readout will
start.
7.2.3
Closed-shutter integration
ID: CAM-REQ-0053
Last Modified: 7/15/2013
Specification
: The camera shall be able to perform exposures without opening the shutter
7.2.4
Max exposure duration
ID: CAM-REQ-0054
Last Modified: 1/6/2011
Specification
: The camera shall be capable of exposures longer than the nominal duration of 15
seconds, but single image specifications need not be met.
7.2.5
Min exposure duration
ID: CAM-REQ-0055
Last Modified: 10/22/2014
Specification
: The camera shall be able to obtain a single exposure with an effective minimum exposure
time of no more than
minExpTime
, with a goal of an effective minimum exposure time of
minExpTimeGoal
.
Discussion
: The camera thermal stability may be affected if the duty cycle differs from the standard 15
second cadence. If the exposure time is shortened from the 15 second nominal, the spacing between
successive exposures might need to be extended to maintain the average readout rate consistent with a
15 second exposure. If the exposure is lengthened from the 15 second nominal, the thermal stability may
also be affected, which may affect photometric accuracy. In addition, as the exposure time uncertainty is
essentially a fixed amount of time, shorter exposures will have proportionally larger fractional uncertainty.
Description
Value
Unit
Name
Minimum exposure time
1
Seconds
minExpTime
Minimum exposure time goal
0.1
Seconds
minExpTimeGoal
7.3 Science data read-out

LSST Camera Subsystem Requirements
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Latest Revision 2/1/2016
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waived without prior approval.
28
Last Modified: 7/11/2013
Discussion:
The science data read-out requirements defined below are refined in the DM to Camera ICD
(LSE-68).
7.3.1
Science Image Identifier
ID: CAM-REQ-0056
Last Modified: 7/11/2013
Specification
: The camera shall deliver each image with a unique identifier per device per exposure.
7.3.2
Cross-talk corrected image data
ID: CAM-REQ-0057
Last Modified: 7/11/2013
Specification
: The camera shall provide cross-talk corrected science pixel data to client subscribers.
Discussion:
The DM will provide the cross-talk coefficients and correction algorithm as defined in the DM
to Camera ICD (LSE-68).
7.3.3
Persistence of raw data
ID: CAM-REQ-0059
Last Modified: 7/29/2011
Specification
: The camera shall persist the raw pixel data for
[CamPersist].
Discussion:
The camera retains the raw pixel data to be able to supply it to consumers on demand.
Description
Value
Unit
Name
Science data buffer capability
2
Days
CamPersist
7.3.4
Raw Image Data
ID: CAM-REQ-0058
Last Modified: 7/15/2013
Specification:
The camera shall provide raw science pixel data in response to a request for one or more
specific images.
7.3.5
Raw data buffer readout
ID: CAM-REQ-0060
Last Modified: 1/6/2011
Specification
: The camera shall be able to transmit the persisted raw data in
[PersistReadout]
in
parallel with routine observing operations.
Description
Value
Unit
Name

LSST Camera Subsystem Requirements
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waived without prior approval.
29
Description
Value
Unit
Name
Science data buffer maximum readout duration
1
Days
PersistReadout
7.3.6
Wavefront data to DM
ID: CAM-REQ-0061
Last Modified: 7/11/2013
Specification
: The camera shall provide wave front data to DM.
7.4 Time Reference
7.4.1
Timestamp Accuracy and Precision
ID: CAM-REQ-0111
Last Modified: 10/22/2014
Specification:
Computer clocks used to produce timestamps shall be synchronized with an observatory
master clock to a precision of
[timestampPrecision]
and an accuracy of
[timestampAccuracy]
, as
given in the table below. This requirement shall apply separately to each computer clock.
Discussion:
The purpose of time synchronization is to ensure that timestamps recorded in the database
are meaningful regardless of which computer generated the timestamp. To achieve this, an observatory
master clock is distributed to all computer hosts that generate timestamps recorded in LSST telemetry.
Current protocols (PTP and NTPv4) allow system clocks to be synchronized well within the requirement.
Timestamps are used to record both internal and external events as observatory telemetry. The
relationship between the timestamp and the actual physical event, expressed as latency/jitter, depends
on both the computer and the hardware (mechanical, electrical, etc.). It is the responsibility of individual
hardware design teams to determine the relevance of latency/jitter. When cross subsystem dependencies
on timestamps exist, additional requirements can be documented in ICDs. The term "precision" is to be
interpreted as a one-sigma statistical measure, and the term "accuracy" as a statistically determined
mean measurement.
Description
Value
Unit
Name
Computer clock timestamp accuracy
0.010
Seconds timestampAccurac
y
Computer clock timestamp precision
0.001
Seconds timestampPrecisio
n
7.5 Filter Operations
7.5.1
Filter swap in place
ID: CAM-REQ-0066
Last Modified: 6/16/2011
Specification
: The internal filter complement of the camera shall be reconfigurable without requiring the
removal of the camera from the telescope.
7.5.2
Filter complement

LSST Camera Subsystem Requirements
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30
ID: CAM-REQ-0067
Last Modified: 7/11/2013
Specification
: The camera shall accommodate [
NumFilters
] filters on board the camera at any time.
Discussion
: This presumes that a filter swap-out for a spare filter requires a daytime access.
Description
Value
Unit
Name
Number of on-board filters
5
int
NumFilters
7.5.3
Filter exchange duration
ID: CAM-REQ-0068
Last Modified: 7/11/2013
Specification
: The camera shall require less than [
FilterchangeDuration
] to change between any two
filters that are resident inside the camera.
Discussion
: This duration covers all required camera operations, but does not include any additional
telescope or OCS times.
Description
Value
Unit
Name
Maximum filter change duration
90
Seconds
FilterChangeDuratio
n
7.5.4
Filter swap-out duration
ID: CAM-REQ-0069
Last Modified: 7/11/2013
Specification
: The Camera shall allow for swapping out any of the on-board filters for a new filter during
the day, with a total time to swap out the filter of [
FilterSwapOutDuration
] after safe access to the
Camera has been established.
Discussion
: This duration covers all required camera operations and verification tests, but does not
include any additional telescope time needed to access the camera or recover.
Description
Value
Unit
Name
Maximum filter swap duration
1.5
Hours
FilterSwapOutDurati
on
7.5.5
Number of filter exchanges
ID: CAM-REQ-0070
Last Modified: 6/16/2011
Specification
: the Camera shall be capable of a total of
[dailyFiltChanges
] plus
[nightlyFiltChanges]
filter changes per day during its design lifetime
Description
Value
Unit
Name
Daily filter changes
8
int
dailyFiltChanges
Nightly filter changes
4
int
nightlyFiltChanges

LSST Camera Subsystem Requirements
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31
7.5.6
Number of filter swap-outs
ID: CAM-REQ-0071
Last Modified: 6/16/2011
Specification
: For design purposes the number of monthly filter swaps shall be at least
[monthlyFiltSwaps]
.
Description
Value
Unit
Name
Minimum number of manual filter swaps per month
2
int
monthlyFiltSwaps
7.6 Camera Power-on
ID: CAM-REQ-0072
Last Modified: 6/16/2011
Specification
: Upon activation, the camera shall be able to initialize itself and be ready for
communication with the OCS without further human intervention. This activation process shall take less
than
[CamActivationTime]
.
Discussion
: This does not place any requirements the camera in terms of being ready to take data. For
example, the Camera cool down (which requires activation) will take considerable longer than the
specified activation time.
This requirement assumes a warm restart or activation with the appropriate computer(s) up and running.
Description
Value
Unit
Name
Camera activation time
1
Minute
CamActivationTime
7.7 Camera Initialization
ID: CAM-REQ-0073
Last Modified: 7/11/2013
Specification:
The camera at power up shall be initialized into a known safe state without human
intervention.
7.8 Camera Stand-alone Operations
ID: CAM-REQ-0074
Last Modified: 7/11/2013
Specification
: The camera shall maintain technical health, safety and status without any other
observatory subsystem operational.
7.9 Camera Engineering and Maintenance
ID: CAM-REQ-0075
Last Modified: 7/15/2011
Specification
: The camera shall provide access to lower level functionality and telemetry to support
engineering and maintenance operations.

LSST Camera Subsystem Requirements
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32
7.10
Remote Operation Capabilities
ID: CAM-REQ-0076
Last Modified: 7/11/2013
Specification:
The camera shall be remotely operable from any of the LSST Facilities or other Project
designated site (e.g. SLAC for camera troubleshooting), subject to cyber security policy. A local operator
shall be always available to regain local control when conditions or safety considerations merit.
Discussion:
This provides the opportunity to establish a single operations center for the various functions
of Data Management. Note that cyber security policies must be enforced.
7.11
Camera Scheduled Maintenance
ID: CAM-REQ-0077
Last Modified: 7/15/2013
Specification
: The camera shall contribute no more than [
CamMaintenanceTime
] of observatory
downtime per year due to planned maintenance requirements.
Description
Value
Unit
Name
Maximum scheduled maintenance per year
7
Days
CamMaintenanceTi
me
7.12
Maintenance Recommendations
ID: CAM-REQ-0078
Last Modified: 7/11/2013
Specification:
The camera team shall provide a preventive maintenance plan to the Observatory.
7.13
Camera Unscheduled Downtime
ID: CAM-REQ-0079
Last Modified: 1/27/2015
Specification:
The Camera shall be designed to facilitate unplanned repair activities expected not to
exceed
CamDowntime
days per year.
Discussion:
This requirement does not invoke the need to verify by reliability analysis. Verification is by
analysis that identifies likely hardware failures and identifies mitigations to minimize downtime caused by
those failures.
Description
Value
Unit
Name
Unplanned downtime per year
10
Days
CamDowntime
7.14
Number of shutter actuations
ID: CAM-REQ-0080
Last Modified: 7/11/2013

LSST Camera Subsystem Requirements
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The contents of this document are subject to configuration control and may not be changed, altered, or their provisions
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33
Specification
: The camera shall be designed for
nRawExpYear
shutter actuations per year.
Discussion
: Includes science and calibration exposures as defined in OSS-REQ-0190 and -0323.
Description
Value
Unit
Name
Minimum number of raw science exposures required to be
supported by the LSST Observatory over the course of a
single year
750000
int
nRawExpYear
7.15
Safety System
ID: CAM-REQ-0081
Last Modified: 7/11/2013
Specification:
The camera shall implement a non-software based safety system in areas where injury or
harm to personnel and or equipment can occur.
7.16
Baseline Performance
ID: CAM-REQ-0082
Last Modified: 6/16/2011
Specification:
The camera shall provide the initial baseline performance as determined during
acceptance testing and system integration and test.
Discussion:
The baseline analysis is a deliverable of the subsystem and will be part of the acceptance
process. It is expected that over time the observatory staff will modify and add to the analysis as
knowledge of the subsystems improves.
7.17
Trend analysis
ID: CAM-REQ-0083
Last Modified: 6/16/2011
Specification:
The camera shall provide a telemetry trend analysis specific to the camera design using
the provided toolkit
Discussion:
It is expected that over time the observatory staff will modify and add to the analysis as
knowledge of the subsystems improves.
8 Camera Environmental Requirements
8.1 Normal Operations
ID: CAM-REQ-0084
Last Modified: 7/15/2013
Specification
: The camera shall meet performance requirements under normal operating conditions as
defined in the table below.

LSST Camera Subsystem Requirements
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34
Description
Value
Unit
Name
The maximum barometric pressure for normal operations at
the summit shall be
normBaroMax
.
775
milibar
normBaroMax
When design considerations require barometric pressure
specifications all summit based systems shall use the mean
pressure
normBaroMean
.
750
milibar
normBaroMean
The minimum barometric pressure for normal operations at
the summit shall be
normBaroMin
.
725
milibar
normBaroMin
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 normHumidityMea
n
The rate of change for design purposes shall be
normTempGrad.
0.7
C/Hour
normTempGrad
The maximum temperature for normal operations at the
summit shall be
normTempMax
.
19.0
Celsius
normTempMax
The 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
When design considerations require operational wind
specifications all summit based systems shall use the extreme
operational wind speed,
normWindMax
.
12
m/sec
normWindMax
8.2 Marginal Condition Operations
ID: CAM-REQ-0085
Last Modified: 7/15/2013
Specification
: The camera shall operate under marginal operating conditions as defined in the table
below, but need not meet specification.
Description
Value
Unit
Name
The temperature rate of change for degraded operations is
marginalTempGradient
2.0
C/Hour
marginaltempGra
dient
The maximum temperature for degraded operations at the
summit is
marginalTempMax
.
30
Celsius
marginalTempMa
x
The minimum temperature for degraded operations at the
summit is
marginalTempMin
.
-5
Celsius marginalTempMin
The maximum free air windspeed for degraded operations at
the summit is
marginalWind
.
20
m/sec
marginalWind
8.3 Survival Condition Operations
ID: CAM-REQ-0086
Last Modified: 7/15/2013

LSST Camera Subsystem Requirements
LSE-59
Latest Revision 2/1/2016
The contents of this document are subject to configuration control and may not be changed, altered, or their provisions
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35
Specification
: The camera shall survive the survival conditions as defined in the table below, but need
not be operating.
Description
Value
Unit
Name
All equipment at the Summit Facility must be capable of
surviving a maximum non-condensing humidity of
survivalHumidity
without damage.
100
Percent
survivalHumidity
All equipment located at the Summit Facility must be capable
of surviving an ambient air temperature of
survivalTemperature.
-10
Celsius survivalTemperatu
re
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 equipment in the interior of the Summit Facility must be
capable of surviving an exterior 10-second wind gust speed of
survivalWindGust.
25
m/sec
survivalWindGust
8.4 Transportation Condition Design
ID: CAM-REQ-0087
Last Modified: 7/15/2013
Specification
: The camera and shipping container shall be designed to withstand the transportation
conditions as defined in the table below.
Description
Value
Unit
Name
During transportation, the effective altitude can change
between sea level and 3000m.
Sea level
to 2700m
Meters
Altitude
Containers have to be designed to limit water, dust, sand and
insect access during transportation
Contamination
During transportation to the summit, some roads have vehicle
weight restrictions.
Gross Vehicle Weight GVW = TBD
Weight/axle = TBD
TBD
kg
GVW
Pressure will change during transportation to the summit from
1000mbar at sea level down to 750mbar at the summit
1000 to
750
milibar
Pressure
The relative humidity range is from 10% to 100% with
condensation for transportation to the summit
10% to
100%
Percent Relative Humidity
Range
Dirt roads will be used during transportation to the summit
with grades up to 16%
16
Percent
Roads
The ambient temperature range or transportation to the
summit is
-15C to
+40C
Celsius
Temperature
Range
The container dimensions are limited by the Puclaro Dam
tunnel located on the road between La Serena and the
summit.
9
Meters
Tunnel
Wind speed may reach up to 45m/s during transportation to
the summit
45
m/sec
Wind Speed
8.5 Design for Operable-Level Seismic Event

LSST Camera Subsystem Requirements
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The contents of this document are subject to configuration control and may not be changed, altered, or their provisions
waived without prior approval.
36
ID: CAM-REQ-0106
Last Modified: 7/12/2013
Specification
: When mounted to the telescope, the Camera shall be designed to operate without any
significant damage following an operable-level seismic event, with accelerations as defined in LSE-80,
the Camera-Telescope Mechanical ICD, req CA-TS-MEC-ICD-0010. “Significant damage” is defined as
any yielding, structural failure, or loss of function that requires more than 40 hours (TBR) to repair after
access and initial inspection.
8.6 Design for Recoverable-Level Seismic Event
ID: CAM-REQ-0107
Last Modified: 7/12/2013
Specification
: When mounted to the telescope, the Camera shall be designed to operate without any
permanent damage following a recoverable-level seismic event, with accelerations as defined in LSE-80,
the Camera-Telescope Mechanical ICD, req CA-TS-MEC-ICD-0028. “Permanent damage” is defined as
any damage to optical elements, damage where repair costs are in excess of $4M (TBR), or where repair
times are longer than 6 months after access, initial inspection, and damage assessment.
8.7 Design for Survival-Level Seismic Event
ID: CAM-REQ-0108
Last Modified: 7/12/2013
Specification
: When mounted to the telescope, the Camera shall be designed to withstand a survival-
level seismic event without catastrophic failure, with accelerations as defined in LSE-80, the Camera-
Telescope Mechanical ICD, req CA-TS-MEC-ICD-0029. “Catastrophic failure” is defined as fracture or
rupture that allows a significant element to separate and fall, or significantly increases the risk of
personnel injury.
Discussion
: The return of the Camera (and observatory) to "normal" operations following a "Survival"
event will be assessed based on actual damage incurred.
9 Standards
9.1 Components Standardization Goal
ID: CAM-REQ-0089
Last Modified: 2/3/2015
Goal:
The Camera should be designed to standardize components within the subsystem and with other
subsystems when component functional, performance, and operational requirements define overlapping
solution spaces.
Discussion:
While it is desired to standardize component selection, it is realized that imposing this as a
strict requirement is not practical due to a variety of factors, including component requirements that may
require selection of unique hardware. However, standardizing components, where practical, supports
many project operational goals, including standardization of operational and maintenance procedures.
Additionally, standardization reduces the number of unique spares that must be stocked, helping reduce
maintenance costs during commissioning and operations. To support the goal of component
standardization, it is recommended that the camera subsystem exchange information with the other

LSST Camera Subsystem Requirements
LSE-59
Latest Revision 2/1/2016
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waived without prior approval.
37
subsystems on an ongoing basis on their component selection to enable choices to be made informed by
what components are already in use. Note: this is a "goal" statement that does not require verification.
9.2 Plans and Standards
ID: CAM-REQ-0119
Last Modified: 9/29/2014
Specification:
The Camera shall develop and document standards and plans for the following:
-Software Standards
-Electrical Standards
-Grounding Plan
-Mechanical Standards
9.3 Safety
ID: CAM-REQ-0093
Last Modified: 7/11/2013
Specification
: The camera shall comply with the LSST Safety Policy (LPM-18) and Hazard Analysis and
Safety Practices (LPM-49).

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