JWST NIRCam Calibration
Peter McCullough,
Don Figer,
James Rhoads
16 September 2004
9/16/2004
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Presentation Outline
• NIRCam Timeline
• NIRCam Optical Layout
• Three viewpoints
– Requirements Trace
– Analysis pipelines: CalNIRCamA, B
– Comparison to NICMOS Goals & Plan for
Commissioning
• Plan Outline: from ETU tests to JWST’s EOL
• Astronomical Sources for Photometry, Astrometry
• Summary
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Not Addressed Here
• Cross-calibrations (to JWST’s NIRSPEC,
FGS; HST; Spitzer)
• WFS, WaveFront Sensing Requirements
– Because only recently completed
– TBR, To Be Reviewed
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NIRCam Timeline
Oct 20-21, 2004
NIRCam PDR
NIRCam CDR
Oct 13, 2005
2007
2008
2009
2010
Deliver
GSW-01
GSW-02
Oct 20, 2005
Begin ETU I&T
Sep 22, 2006
Begin FM I&T
Launch
2011
Commissioning
completed
6 months after launch
PDR is Preliminary Design Review
CDR is Critical Design Review
GSW-01 defines reduction algorithms
GSW-02 defines reference files and their format
ETU is the Engineering Test Unit for NIRCam
FM is the Flight Model for NIRCam
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Optical Layout
From OTE
3
9
10
11
12
4
5
6
2
1
7
14
1
Pick-Off Mirror Assembly
2
Coronagraph
3
First Fold Mirror
4
Collimator Lens Group
5
Dichroic Beamsplitter
6
Long Wave Filter Wheel Assembly
7
Long Wave Camera Lens Group
8
Long Wave Focal Plane Housing
9
Short Wave Filter Wheel Assembly
13 10
8
15
Short Wave Camera Lens Group
11
Short Wave Fold Mirror
12
Pupil Imaging Lens
13
Short Wave Focal Plane Housing
14
ICE Interface Panel
15
FPE Interface Panel
Light source
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Flat Field Sources are in Pupil Wheel
Pupil Wheel
Pinhole Integrating
Cavity Assembly
Thermal
Radiant Source
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Flat Field Sources Design Concept
Optical Integrating Cavity located on Pupil Wheel
Radiant Source – Fixed to Bench
Pinhole Aperture
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Pinhole Integrating Cavity
Pinhole aperture (1 shown)
Exiting light paths
Incident light
from radiant source
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NIRCam Optics & Mounts PDR, September 8, 2004
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Lyot Coronagraph Occulting Masks &
Pinhole Sources
Occulting Mask
Substrate
LED Source
Calibration pinhole
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NIRCam Optics & Mounts PDR, September 8, 2004
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Three Viewpoints
to Calibration Plan
1. JWST+NIRCam Requirements
2. Software Pipeline (IDTL, Calnica, …)
3. Prior Calibration Experience (NICMOS, WFC3, …)
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Requirements Trace to
Calibration Plan
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Requirements: detector
3.7.3.10 Pixel Operability
3.7.3.11 SCA noise
3.7.3.12 Read noise
Electrical crosstalk
3.7.3.13 between pixels
3.7.3.14 Radiometric Stability
Latent or Residual
3.7.3.15 Images
3.7.3.16 Radiation immunity
9/16/2004
While simultaneously meeting all requirements,
the SCA operability shall be > 98%
The total noise per pixel shall be < 9 e- (rms) in an
integration period of 1000secs. This will be
measured with two groups of 8 samples or
Frames,
The read noise for a single read shall be < 15 e(rms)
The electrical crosstalk between pixels shall be <
5%
The radiometric stability over 1000seconds shall be
< 1%
Latent or residual images when measured at the
same integration time as was use for the near
saturation image shall be <0.1% after the 2nd read
following an exposure of > 80% of full well
No more than 4% of the pixels will be degraded
from their original performance after 5.5 years at
L2 within NIRCam. This may be verified with
analysis and agreed upon assumptions of TID at
L2.
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Requirements: coronagraphy
2.3 Coronagraphy
2.3.1 General
Characteristics
Little
or no influence
BTG2004
3.3.1.2.1
NSRD
page 2
3.3.2.2.1 Coronagraph Capability
2.4.3 Coronagraphic Science
We assume that the coronagraph will be allowed to
have little or no influence on the design or
operation of the telescope and minimal impact on
design of NIRCAM.
NIRCam shall provide a coronagraph capability in
all four of the imaging channels. This will be
enabled by the placement of coronagraph image
masks at the edge of the telescope focal surface
and selection of a coronagraph wedge in each of
the filter wh
NIRCam should be able to detect objects
as small as 1 MJ located outside 10-20 AU of the
star. For stars 5 Gyr old, Jupiter-mass objects
are detectable to ~5 pc.
10 AU at 5 pc is 2 arcsec
5 AU at 10 pc is 0.5 arcsec
MSRD
3.3.1.2.2
3.3.1.2.3
BTG2004
6.5 Coronagraphic Science
ND Filters on
3.3.2.2.2 Coronagraphic Slide
Coronagraphic mask
3.3.2.2.3 stability
Fig 15 Target Acquisition
On-board centroiding
3.8.1.2
Spacecraft Coarse Roll
Control
OBS-1621
Table 6-2 states that AB mag = 18, the bound
planet brightness is based on a 2-Jupiter mass
planet 5 AU from an M star 10 parsecs from Earth.
Neutral Density filters of density n = 3 (TBR) and
> 2arcseconds (TBR) diameter shall be utilized to
allow for centroiding bright sources.
Once NIRCam has reached it operating
temperature, the coronagraphic occulting mask
slide shall remain within 0.005 (TBR) arcseconds
of its nominal position relative to the pixels on the
FPAs over a timescale of 1 month (TBR).
to 0.010 (TBR) arcseconds 1-sigma each axis
To support coronagraphy, ISIM C&DH shall be
capable of positioning a point source on a
coronagraphic spot with an accuracy of 0.005 arcseconds (TBR).
During a science target observation, the Spacecraft
coarse roll control shall be less than or equal to 6.5
arcseconds RMS.
Software Pipeline Trace to
Calibration Plan
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CalNIRCamA
Flowchart
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HST Heritage Trace to
Calibration Plan
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Trail Blazers
NICMOS
WFC3
NIRCam
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NICMOS Calibration Goals
NIRCam will have
similar goals, except
no polarization and
no grism,
except WFS grism
in the Dispersed
Hartmann Sensor,
which is only used
in commissioning.
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NIRCam Calibration Plan
duration in
NICMOS SMOV
NICMOS # NICMOS Name
1
2
3
4
SMR-2021/Rev A
MacKenty, J. 1997.01.31
to HOLD Mode
Internal parallel operation
memory load and dump
field offset mechanism
5 filter wheel mechanism
6 Electronic noise; SAA contour
7 Dewar heaters Setpoint
adjustment
8 Transfer function
9 Target Acquisition
10 NICMOS to FGS Astrometric
Calibration - aperture locations
11 Plate Scale and Astrometric
Calibration
12 Coarse Optical Alignment
13 Fine Optical Alignment
14 Point Spread Function
Characterization
15 Persistence
16 IntFlat Transfer and Stability
17 HST thermal background
18 Absolute photometry
19 Differential Photometry
20 Detector noise and Dark
characterization
Commissioning
Maintenance
CFT
0:02
3:00
1:30
10:00
CPT
A*
M
B,L
G
V1
ISIM Plum
A*
A*
E
B,C,G
F
H
H
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.
.
E,R
.
.
.
G
M
n
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J
L
Y
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K
Y
A,B
n
B,C
B,I
Y
B
J
Y
N
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C,O,R
C,S
C,S
.
Y
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A,H,R ?
I
P,Q
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Y
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.
I
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24:00:00
0:05
0:40
5:00
5:00
1:30
J
11:00
J
16:00 E,F,H
,I
11:00
3:30
9:30
16:00
6:30
18:00
8:00
21 Coronagraphic Performance
verification
22 Limb avoidance Determination
23 Thermal Check on COSTAR
9:00
15:00
deploy
Grism Validation
Focus Monitor
Scattered Light Determination
SI Parallel Operations
10:00
16:30
1:30
9:00
4:30
24
25
26
SI-1
Ground test
Cycle 7
(hh:mm)
C
B
D
A
B
E
E
A
I
B
C
J
F
G
H,I
K
D
H
C,D
NIRCam Calibration Plan
Outline
Cold Functional Test (CFT) @ LMATC
Comprehensive Performance Test (CPT) @ LMATC
+V1 Down Test @ GSFC
ISIM Test @ GSFC
JWST Test @ Plum Brook or equivalent
On Orbit Commissioning @ L2
Maintenance Calibration @ L2
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Cold Functional Test
A.
B.
C.
D.
E.
F.
G.
H.
I.
J.
BiasDark & Readnoise
Flats: lamp visible thru all filters
Coronagraphic emitters
PIL (Pupil Imaging Lens) – repeatability of PIL, PW
WFE using NOTES (NIRCam OTE Simulator)
WFE using Coronagraphic emitters
DHS rotation
FAM (Focus Adjust Mechanism, “pickoff mirror”)
Confocality of LW and SW FPAs
Alignment of LW and SW FPAs
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Comprehensive Performance Test
(1 of 2)
A. Repeat CFT
B. Explore behavior by varying
1. integration time
2. Source brightness
3. Sampling
4. Co-adding
C. Subarrays
D. FAM calibration using NOTES
E. Linearity, Saturation, Latency
F. Thermal tests (SCAs and mechanisms)
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Comprehensive Performance Test
(2 of 2)
G.
H.
I.
J.
K.
L.
M.
Flight-like scripts using SITS
Ghosts, Glints, & Diffuse scattered light using NOTES
Dark position is indeed dark
Coronagraphic slide survey (mapping)
DHS dispersion using NIRCam’s R=100 filters
Data rate & volume stress test
Fault protection test
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+V1 Down Test
A. WFE using NOTES
B. Alignment of cubes (warm vs cold)
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ISIM Test @ GSFC
A.
B.
C.
D.
E.
F.
G.
H.
Repeat CFT
Readnoise thru flight (or flight-like) wiring
EMI/EMC with parallel ops’ with FGS (& other SIs)
Stray light with parallel ops’..
Fault protection
Subarrays
Data rate and volume stress test
Flight-like scripts using ICDH
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JWST Test @ Plumbrook
A.
B.
C.
D.
E.
F.
Repeat CFT
FAMs, confocality of modules
PIL: OTE pupil shear compensation using FAMs
WFS&C
Subarrays
Data rate & volume
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On-Orbit Commissioning (1 of 2)
A.
B.
C.
D.
E.
F.
G.
H.
I.
J.
K.
Alignment
Pupil Shear
Radiometric Calibration
Dark current and read noise checks
Internal throughput checks
Flat field measurements
FPA tune-up – biases, offset voltages, etc.
Observing mode checkouts
Focus confirmation on stellar sources
Point spread function characterization
Distortion mapping – confirming plate scales and distortions
across the field of view
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On-Orbit Commissioning (2 of 2)
L. Focal plane survey – locations of the NIRCam fields of view
relative to FGS
M. Coronagraphic mode checkout – verifying emitters, ND spots,
offsets to the coronagraphic masks, algorithms for
centroiding, coronagraphic contrast
N. Latent image verification
O. Sensitivity/confusion limit checks
P. Off-axis glint checks
Q. Scattered light checks
R. Routine calibration activities
S. Checkout of candidate calibration sources
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On-orbit Maintenance
Programs for NIRcam, to date.
SODRM #
421
NIRCam Flat Field Monitoring
422
423
NIRCam Dark Monitoring
NIRCam Photometric Monitoring
424
NIRCam Short term Astrometric
Monitoring
NIRCam Long Term PSF
Monitoring
425
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Title
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SODRM Program 423
Program No.: 423
As-of date: 2/23/04
Program title: NIRCam Photometric Monitoring
Synopsis: The goal of this proposal is to monitor the stability of NIRCam’s
photometric calibration. The observations will be carried out twice a year. It
is assumed that the photometric standard stars (or even better two secondary
calibrator fields) will have been observed during the commissioning.
Sample and sky coverage: Two standard stars suitably positioned.
Instruments and observing configurations: 60s in each filter.
Scheduling requirements or constraints: These are primary external
observations.
Visit scenarios: 2000s visit plus overheads
Total program time needed (days): 1
Program written by: Massimo Stiavelli and Peter McCullough
Date first written: 2/23/2004
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NIRCam Photometric Calibration
Clusters are chosen based upon suitability to solar-analog method
of calibration (Campins, Rieke, Lebofsky 1985):
–Solar
–Color, B-V0 = 0.6 to 0.7
–Age < 8 Gyr (so solar-temperature dwarfs still exist)
–Metallicity, Fe/H ~ 0
–Low extinction, E(B-V) < 0.2
–Rich and compact, in order to permit robust selection from
multiple candidates in NIRCam FOV
–Distance modulus, m-M > 11.7, d > 2200 pc presumes
– Sun’s Mv = 4.8; V-K = 1.5
– K=15 stars don’t saturate in quickest MULTIACCUM (TBR)
– Subarray use is TBD
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Stauffer, NIRCam Sci Team Meeting, May 2003
NIRCam cf. 2MASS
2MASS K-band image
(SNR=10 at K=15)
NGC 2420
NIRCam saturates at
K~15 unless subarray is
used.
= solar type star
= NIRCam FOV
(location is TBD)
Other open clusters that meet E(B-V), m-M, [Fe/H] criteria:
NGC 2506, 6791, 2266, 2243, Mel 66, Berk 39
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NIRCam Astrometric Calibration
We want to know how to do this: (x,y) (α,δ)
• HST observations of globular clusters are ideal
• A priori astrometry (easy way fewer NIRCam exposures)
• High density of stars within NIRCam FOV (2’x4’)
• 100,000 stars, not too bright (K > 15)
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NIRCam Calibration Summary
•
•
•
•
Requirements traced to plan
Heritage from NICMOS, WFC3, and ACS; IDTL
Basic calibration steps planned out
Calibration achievable on orbit
– Lamps are inside NIRCam, also dark slide
– Robust against changes to on-orbit environment
• Need to consider
–
–
–
–
WFS requirements
Cross-calibrations (to NIRSPEC, FGS, HST, Spitzer)
Saturation limit of NIRCam
Commissioning schedule for arbitrary launch date
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Backup Slides
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NIRCam Cheat Sheet
Cheat
Sheet
Pixel Formats and Scales
Arm
Short
Long
λ-range
0.6 - 2.3µm
2.4 - 5.0µm
Pixel Format
4080x4080*
2040x2040
Pixel Scale
0.032“
0.065"
Long and short arms view same area on sky through a dichroic. Redundant A&B modules view adjacent areas on sky (separated by ~25")
*Has ~6" gaps between SCAs.
Detector Performance Requirements
Total Read Noise
Single Read Noise
Dark Current
QE
Well depth
Min. exposure time
Pixel size
Detector Max Op T
≤ 9e- in 1,000 secs
~14 e≤ 0.01 e/sec
≥ 80%
~90,000 e10.6 sec (full frame)
10µsec x No. of pixels (sub-array)
18µm x 18µm
80K, short-λ,42K, long-λ
Flat field sources illuminate back half of NIRCam optical train only.
Coronagraphy uses focal plane masks moved into detector FOV using wedge mounted with pupil wheel mask.
Flux Conversion: 0.038 e-/sec/nJy for F200W
Sensitivity: F200W 10,000secs 10-σ = 10.4 nJy, F444W , 10,000secs 10-σ = 24.5 nJy
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Filters
Revised Filter Set for Each Imaging Module
(subject to further change)
Short - λ Arm
Long - λ Arm
Filter Wheel
Pupil Wheel
Filter Wheel
Pupil Wheel
F070W
Imaging pupil
F270W
Imaging pupil
F090W
Flat field source
F357W
Flat field source
F110W
Outward pinholes
F444W
Outward pinholes
F150W
Coronagraph pupil 1
F250M
Coronagraph pupil 1
F200W
Coronagraph pupil 2
F300M
Coronagraph pupil 2
F140M
WFS dispersive #1
F335M
F241N
F163M
WFS dispersive #2
F430M
F256N
F183M
WFS weak lens 1
F460M
F469N
F210M
WFS weak lens 2
F405N
TBD Filter
F164N
WFS weak lens 3
F480M
TBD Filter
F187N
F212N
F390M
TBD Filter
WFS Filter
F108N
F360M
TBD Filter
Filter Names: FXXXR XXX=Center λ in 100xµm R= (W for R=4, M for R~10, N for R=100)
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CalNIRCamB
Concepts
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Not included
in current
contract of
S&OC.
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Solar Analog Method
• Adopt V magnitude for Sun as V = -26.76 +/-0.02
(Hayes 1985; Campins et al 1985; Bessel et al 1998)
• Convolve filter/detector/telescope response curves for NIRCAM
with model (Kurucz) A0 star. Define colors of the A0 star to be
0.00.
• Above 2 steps yield fluxes for zero mag for all NIRCAM filters.
• Convolve filter/detector/telescope response curves for NIRCAM
with solar spectrum; yields predicted NIRCAM fluxes for solar
analogs (use Colina et al. 1996 solar spectrum)
• Obtain NIRCAM observations of solar analogs in open clusters
(e.g. NGC2420, NGC 6791)
• Do LS fit of predictions vs. observations for AV and distance. If
get good fit and small residuals, you are done. If not, attempt to
determine if problem is with assumptions or with stars.
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Stauffer, NIRCam Sci Team Meeting, May 2003
Problems for NIRCAM Usage of
Solar Analog Method
• NIRCAM saturation at K ~ 15 mag
• Traditional application of method relies on identifying (field)
stars with spectra (or Teff/log g) approx. identical to Sun,
using high resolution spectra and optical photometry.
• K > 15 limit precludes traditional selection method.
• Even with alternate selection technique, K > 15 limit very
likely means standards will have non-zero reddening, poorly
known distance and possibly poorly known metallicity
• Proposed solution = use Solar Analogs in Open Clusters
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Stauffer, NIRCam Sci Team Meeting, May 2003