TIPS/JIM
February 21, 2013
Agenda:
HST Update (Ken Sembach) INS Division News (Jerry Kriss)!
Introduction to Mid-Infrared Instrument Team (Karl Gordon)!
How Post-Flashing Can Help CTE in Some UVIS Images (Jay
Anderson)
JWST SODRM 2012 Effort (Karl Gordon)
Next TIPS/JIM: March 21, 2013
1
Mid-InfraRed Instrument
Team
Mid-Infrared Instrument (MIRI)
MIRI @ GSFC
Karl D. Gordon
Space Telescope
Science Institute
STScI
TIPS/JIM
21 Feb 2013
MIRI Observing Capabilities
(only JWST instrument observing from 5-28 µm)
Imaging
MIRI Field-of-View
Coronography
Phase
Lyot
Integral Field
Spectroscopy
Low-Resolution
Slit Spectroscopy
Imaging
FOV: 79” x 113”
● diffraction limited @7 µm
● 9 broad filters from 5.6 to 25.5 µm
●
Imaging: Filter Selection
FWHM 0.2” – 1”
F560W - F2550W
4
Coronography
●
3 4QPM (no central spot)
–
●
10.65, 11.4, & 15.5 µm
1 Lyot (central spot)
–
23 µm
LRS – Low
Resolution
Spectroscopy
●
●
●
R ~ 100
–
5-10 (14) µm
–
Double prism
–
0.6”x5.5” aperture
–
Filter to remove short
wavelength overlap
Slit
Slitless
–
No slit
–
Non-dithered exoplanet
observations
–
No filter
MRS - Medium Resolution Spectroscopy
●
R ~ 3000, 4 nested IFUs
●
2 detectors
●
3 grating settings to get full 5-28.2 µm spectra
●
3.7” x 3.7” to 7.7” x 7.7” FOVs
MRS: Grating Selection
Select one sub-band at a time
(A-”short”,B-”medium”, or C-”long”) or ALL
●
FOV (“)
IFU1A
IFU1B
IFU2A
slice width # slices sub-band
3.7x3.7
4.5x4.7
6.1x6.2
0.18
0.28
0.39
21
17
16
 range ( m)
short
4.87-5.82
medium
5.62-6.73
long
6.49-7.76
short
7.45-8.90
medium
8.61-10.28
long
9.94-11.87
short
11.47-13.67
medium
13.25-15.80
long
15.30-18.24
MRS Overview
~9”
Each channel’s field of view is
sliced, dispersed and detected.
Channel 1
(4.9 - 7.7 µm)
Channel 2
(7.4 - 11.8 µm)
Channel 3
(11.4 - 18.2 µm)
Channel 4
(17.5 - 28.8 µm)
Wavelength/Velocity
Focal Planes
Mike Ressler (JPL)
Detectors
Si:As
Focal Plane
Electronics
MIRI CryoCooler = Cooling to ~6K
Part of Telescope
STScI MIRI Team
Rachel Anderson
Christine Chen
Misty Cracraft
Karl Gordon
PPS
Calibration
Calibration
Lead
Dean Hines
Operations
Charles Lajoie Klaus Pontoppidan
Operations
PPS
Thomas Wheeler
Engineering
Global MIRI Team
MIRI Principle Investigators
Gillian Wright
Instrument PI
U. of Edinburgh
George Rieke
Science PI
U. of Arizona
“MIRI Day” (May 9, 2012)
Handover of MIRI to NASA
Status & Current Efforts
●
●
Instrument delivered (2012)
–
Extensive testing of flight module
–
Continued testing of flight-like detectors at JPL
Optimizing phase
–
●
●
●
Combined effort of global MIRI team (including STScI members)
Operations
–
Baseline algorithms delivered
–
Optimizing based on studies (inc. SODRM 2012)
Data reduction algorithms
–
Baseline algorithms from instrument team (Spring 2013)
–
Next 2-3 years, combined effort to improve algorithms
Front End (PPS/ETC)
–
Streamlining and improving user experience
TIPS/JIM
February 21, 2013
Agenda:
HST Update (Ken Sembach) INS Division News (Jerry Kriss)!
Introduction to Mid-Infrared Instrument Team (Karl Gordon)!
Solar System Science with JWST (Dean Hines)
JWST SODRM 2012 Effort (Karl Gordon)
Next TIPS/JIM: March 21, 2013
1
Solar System Science
with JWST!
Dean C. Hines
Space Telescope Science Institute
JWST Imaging Modes!
Mode
Imaging
Aperture Mask
Interferometry
Coronography
4/4/13
Instrument
Wavelength
(microns)
Pixel Scale
(arcsec)
Full-Array*
Field of View
NIRCam*
0.6 – 2.3
0.032
2.2 x 2.2′
NIRCam*
2.4 – 5.0
0.065
2.2 x 2.2′
NIRISS
0.9 – 5.0
0.065
2.2 x 2.2′
MIRI*
5.0 – 28
0.11
1.23 x 1.88′
NIRISS
3.8 – 4.8
0.065
------
NIRCam
0.6 – 2.3
0.032
20 x 20′′
NIRCam
2.4 – 5.0
0.065
20 x 20′′
MIRI
10.65
0.11
24 x 24′′
MIRI
11.4
0.11
24 x 24′′
MIRI
15.5
0.11
24 x 24′′
MIRI
23
0.11
30 x 30′′
STScI
DCH - 2
NIRCam Imaging!
4/4/13
STScI
DCH - 3
MIRI Imaging!
1.23′
1.88′
4/4/13
STScI
DCH - 4
NIRISS: Non-Redundant Mask!
4/4/13
STScI
DCH - 5
NIRCam & MIRI Coronagraphs!
4/4/13
STScI
DCH - 6
JWST Spectroscopy Modes!
Mode
Slitless
Spectroscopy
Multi-Object
Spectroscopy
Single Slit
Spectroscopy
Integral Field
Spectroscopy
4/4/13
Instrument
Wavelength
(microns)
Resolving Power
(λ/Δλ)
Field of View
NIRISS
1.0 – 2.5
150 2.2′ x 2.2′
NIRISS
0.6 – 2.5
700
single object
NIRCam
2.4 – 5.0
2000
2.2′ x 2.2′
NIRSpec
0.6 – 5.0
100, 1000, 2700 3.4′ x 3.4′ with 250k
0.2 x 0.5′′ microshutters
100, 1000, 2700 slit widths
0.4′′ x 3.8′′
0.2′′ x 3.3′′
1.6′′ x 1.6′′
NIRSpec
0.6 – 5.0
MIRI
5.0 – ~14.0
~100 at 7.5 microns
0.6′′ x 5.5′′ slit
NIRSpec
0.6 – 5.0
100, 1000, 2700
3.0′′ x 3.0′′
MIRI
5.0 – 7.7
3500
3.0′′ x 3.9′′
MIRI
7.7 – 11.9
2800
3.5′′ x 4.4′′
MIRI
11.9 – 18.3
2700
5.2′′ x 6.2′′
MIRI
18.3 – 28.8
2200
6.7′′ x 7.7′′
STScI
DCH - 7
NIRISS Wide-Field Slitless Spectroscopy!
4/4/13
STScI
DCH - 8
NIRISS Single-Object Slitless Spectroscopy!
4/4/13
STScI
DCH - 9
NIRSpec Apertures!
4/4/13
STScI
DCH - 10
NIRSpec Micro-Shutter Array!
4/4/13
STScI
DCH - 11
NIRSpec Micro-Shutter Array!
4/4/13
STScI
DCH - 12
Example Solar System Observations!
•  Trans-Neptunian Objects – Icy Dwarf Planets & KBOs
•
•
•
•
4/4/13
–  Thermal imaging & Spectroscopy
–  NRM interferometry for astrometry of binaries
Asteroids & Comets
–  Thermal imaging & Spectroscopy
–  NRM interferometry for astrometry of binaries
Mars – Spectroscopy
–  Full disk, seasonal variations
Giant Planets
–  Isolated cloud decks of Jupiter & Saturn
–  Full disk observations of Uranus & Neptune
Icy Moons – Titan, Triton, Enceladus
STScI
DCH - 13
Bright Solar System Objects!
•  Mars: NIRSpec, NIRCam (Long Wavelength Channel)"
•  Jupiter: MIRI (MRS <10 µm and FND), NIRCam, NIRSpec"
•  Saturn: MIRI (MRS, imaging, FND), NIRCam, NIRSpec
•  Uranus: MIRI (spectra and imaging), NIRCam, NIRSpec
•  Neptune: MIRI (spectra and imaging), NIRCam, NIRSpec
Object
Angular
Diameter
(arcsec)
Diameter (km)
2 µm Spatial
Resolution (km)
IFU size (km)
3!!x3!!
Mars
7
6800
68
2900
Jupiter
37
140,000
265
11,350
Saturn
17
120,000
490
21,180
Uranus
3.5
51,000
1020
43,700
Neptune
2.2
50,000
1590
68,180
Pluto @ 35 AU
0.1
2400
1600
72,000
4/4/13
STScI
DCH - 14
Giant Planet Imaging with NIRCam!
4/4/13
STScI
DCH - 15
Saturn Rings!
4/4/13
STScI
DCH - 16
NIRSpec IFU: Uranus!
Uranus image from 12 July 2004,
solar elongation 133°
Ecliptic
Image from Keck Observatory
4/4/13
STScI
DCH - 17
Slit Observations of Neptune!
Neptune image from 27 July 2007,
solar elongation 163°
0.2 x 3.3 arcsec slit
Ecliptic
Image from Keck Observatory
4/4/13
STScI
DCH - 18
MIRI IFU of Uranus!
Uranus image from 12 July 2004,
solar elongation 133°
5-7.8 µm channel
3.7x3.7 arcsec
Ecliptic
Image from Keck Observatory
4/4/13
STScI
DCH - 19
MIRI IFU Comet Temple 1!
5-7.8 µm
channel
3.7x3.7 arcsec
HST Image (Feldman & Weaver)
4/4/13
STScI
DCH - 20
MSA of Comet Temple 1!
NIRSpec microshutter pseudo
long slit
shutters opened on diagonal
Each open shutter is 0.2x0.46
arcsec
HST Image of Comet
Holmes (2007)
4/4/13
STScI
DCH - 21
NIR Spectroscopy of Icy Moons!
4/4/13
STScI
DCH - 22
Light Curve for Pluto!
4/4/13
STScI
DCH - 23
Mission Requirements for Moving Targets!
•  Capability to observe moving targets with apparent rates up to
30mas/second
(Includes Mars and beyond, but not all possible comets)
•  Pointing stability of 50 mas (3σ) for rate of 3 mas/second
Minimum rate
(mas/sec)
Maximum rate
(mas/sec)
Time to move 2
arcmin at min
rate (hrs)
Time to move 2
arcmin at max
rate (hrs)
Mars
2.5
28.6
13.3
1.2
Ceres
1.0
18.4
33.3
1.8
Jupiter
0.07
4.5
476
7.4
Saturn
0.04
2.9
833
11.4
Uranus
0.02
1.4
1667
24
Neptune
0.004
1.0
8333
34
Pluto
0.16
1.0
208
34
Haumea
0.35
0.89
95
37
Eris
0.22
0.56
152
59
Object
4/4/13
STScI
DCH - 24
•
Schematic for Moving Target Observation!
MT offset command repositions Guide Star and initiates moving guide star tracking
–  MT ephemeris defines guide star position such that science target is in SI aperture
–  ACS iterates offset slew calculation and computes guide star position P3 at time T3
–  ACS returns T3 and P3 to ISIM Scripts; ISIM sets up FGS for track mode
–  ACS executes offset slew from P2 to P3 prior to T3
TE = End of Ephemeris
–  ACS waits until T3 and then starts MT tracking of guide star
Science exposure ends
6
Moving Target GS Track
Commanded Guide Star
position for ID/ACQ
Acquired
GS position
2
1
Science exposure starts
5
4
Executed offset slew from P2 to P3
Remove slew error
3
32x32 track box follows guide star
GS position P3 at time T3
not drawn to scale!
4/4/13
TS = Start of Ephemeris
DCH - 25
Recent Progress on Moving Target Capability!
•
•
•
•
•
•
•
•
•
Moving targets with apparent rates up to 30 mas/second
Includes Mars and beyond, but not all possible comets
Pointing stability of 0.050 arcsec (3σ) for rate of 0.003 arcsec/second
Defined the operational concept and the commands/telemetry
exchanged between observing scripts and spacecraft attitude control
for autonomous execution of moving target observations.
Preliminary Design Review for moving target capability will be in
December 2012
Will include first simulations of moving target pointing performance
using non-linear stability analysis with dynamics model for JWST
observatory
Moving target Critical Design Review will be in summer 2013
Moving target observations will be supported in first year of JWST
observing
Cycle 1 Call for Proposals in 2017
4/4/13
STScI
DCH - 26
Recent Progress on Moving Target Capability!
•
•
•
•
•
•
•
•
•
Moving targets with apparent rates up to 30 mas/second
Includes Mars and beyond, but not all possible comets
Pointing stability of 0.050 arcsec (3σ) for rate of 0.003 arcsec/second
Defined the operational concept and the commands/telemetry
exchanged between observing scripts and spacecraft attitude control
for autonomous execution of moving target observations.
Preliminary Design Review for moving target capability will be in
December 2012
Will include first simulations of moving target pointing performance
using non-linear stability analysis with dynamics model for JWST
observatory
Moving target Critical Design Review will be in summer 2013
Moving target observations will be supported in first year of JWST
observing
Cycle 1 Call for Proposals in 2017
4/4/13
STScI
DCH - 27
SODRM 2012 by Category!
Syste
m
Calibra
tion
Solar
Exoplanets
Distant
Galaxies &
Cosmology
Galactic
Nearby
Galaxies
4/4/13
STScI
DCH - 28
Distribution of Total Exposure Times
per target per instrument!
Cumulative Histrogram:"
Median exp. = 0.38 hours."
Mean exp. = 1.84 hours."
Solar System!
Exoplanets"
Galactic"
Nearby Galaxies, "
Distant Galaxies & Cosmology"
Calibration."
4/4/13
STScI
DCH - 29
Solar System Programs!
1.  Asteroids – NIRSpec & MIRI slit spectroscopy
2.  Bright Comets – NIRSpec & MIRI IFU, NIRCam imaging
3.  Ice Giants – NIRSpec & MIRI IFU, NIRCam, MIRI Imaging
4.  Icy Dwarf Planets – NIRSpec spectroscopy, MIRI 25µm imaging
5.  KBOs – NIRSpec slit spectroscopy, NIRCam & MIRI imaging
6.  Mars – NIRSpec & MIRI IFU spectroscopy
7.  Outer Planet Satellites – NIRSpec & MIRI slit spectroscopy
8.  Periodic Comets – NIRSpec & MIRI slit spectroscopy
4/4/13
STScI
DCH - 30
JWST & Solar System Science!
•  JWST is a powerful, general-purpose observatory with the
capabilities to address a wide range of scientific questions:
–  From measuring the first light in the universe
–  To the detailed study of our Solar System
•  JWST Operations is planning for Solar System Science
–  Moving target capabilities
–  Bright object modes
–  SODRM studies for exercising the system and
optimizing efficiency
•  The JWST Project encourages strong participation from
the Solar System Science Community
4/4/13
STScI
DCH - 31
Fin
4/4/13
STScI
DCH - 32
TIPS/JIM
February 21, 2013
Agenda:
HST Update (Ken Sembach) INS Division News (Jerry Kriss)!
Introduction to Mid-Infrared Instrument Team (Karl Gordon)!
Solar System Science with JWST (Dean Hines)
Recent Wavefront Control with Hubble (Matt Lallo)
Next TIPS/JIM: March 21, 2013
1
TIPS/JIM 21 Feb 2013
TEL Group
HST’s Recent Wavefront Control
M. Lallo & Colin Cox
(for Telescopes Group)
TIPS/JIM 21 Feb 2013
Hubble’s Optical Telescope Assembly (OTA)
TIPS/JIM 21 Feb 2013
TEL Group
• 2.4 meter f/24 Ritchey-Chrétien (RC) Cassegrain:
- ~20 arcmin FOV suited for imaging
- RC design produces no coma or 3rd order spherical aberrations across the field
- HST’s implementation was flawed, resulting in ~λ/2 spherical aberration
- Current Science Instruments correct the aberration internally
.
FGSs
Axial
Science
Instruments
+ _
Radial
SI
Secondary Mirror
Diameter = 0.31m
Radius of curv. = -1.36m
Multiple rings of
thermal sensors
used by focus
model
OTA METERING TRUSS
4.91m (PM to SM)
1.5m
FOCAL
SURFACE
System
Directions of Secondary
Mirror “piston” or “despace”
movements which alter
focus.
• f/# = 24
• Magnification = 10.43
• 1 micron Sec. Mirror despace = 6.1 nm
RMS wavefront error (focus aberration)
Primary Mirror
Diameter = 2.4m
Radius of curv. = 11.04m
33% central obscuration
Hubble’s Optical Telescope Assembly (OTA)
TIPS/JIM 21 Feb 2013
TEL Group
• Metering Truss
- Thermally passive graphite-epoxy truss/ring structure
- Locates the Primary & Secondary mirrors
- 48 tubular elements matched by measured CTE to minimize overall bending
- Truss constrains mirrors non-axial motions to undetectable levels over the
wide temperature ranges associated with LEO
• Primary & Secondary mirrors
- Actively heated. Controlled to ~ 1ºC
- Exhibit no measurable figure changes
- Primary: 24 actuators for low-level figure
control (not used)
- Secondary: 6 actuators in conventional 3
bipod arrangement
TIPS/JIM 21 Feb 2013
TEL Group
Optical Alignment & Wavefront Changes
• Point Spread Function (PSF) from OTA mainly exhibits focus changes over
time:
- Symmetric dimensional changes in the truss (lengthening/shortening)
- Stable mirror figures
- Any low levels of tip/tilt at the Secondary result in FOV shift and nonradially symmetric aberrations like coma or astigmatism at levels
below our practical abilities to detect.
ACS/HRC Focus Measurements & Lightshield Breathing Model
0.0
• Focus changes occur on a number of different
timescales:
1. HST 96 min orbit (temp.-driven)
2. Days (temp.-driven by attitude changes)
3. Long-term (physical shrinkage of the truss)
Focus (in microns @ Secondary Mirror)
-0.5
-1.0
-1.5
-2.0
-2.5
-3.0
-3.5
-4.0
-4.5
-5.0
17.00
17.25
17.50
17.75
18.00
18.25
18.50
18.75
19.00
Hours (Day 2005.142)
19.25
19.50
19.75
20.00
20.25
20.50
Focus Variations & Evolution
TIPS/JIM 21 Feb 2013
TEL Group
• Temperature-driven focus variations:
- do not trend long term
- have been modeled over the years with reasonable success (Cox &
Niemi 2011, DiNino et al. 2008, Hershey 1998, Bély 1993)
- Peak to peak focus variations typically ~ 6 µm Secondary mirror axial
motion (“despace”) but can be greater.
- are not actively corrected by moving the Secondary mirror
• Long term focus evolution from truss shrinkage:
- ~150 microns over HST life (total 0.003% of truss length)
- Fit by a double exponential
- Temperature-driven variations add +/–2.7 microns rms of “scatter”
- Modeling reduces this to +/–1.5 microns
- is corrected by moving the Secondary mirror in despace
NOTE: 1 micron of Secondary mirror despace induces 6.1 nanometers of RMS wavefront error
(focus) at the HST focal plane, so typical focus variations induce ~37 nm rms wavefront error)
Aberration Measurements - Phase Retrieval
TIPS/JIM 21 Feb 2013
TEL Group
• STScI has used parametric phase retrieval (Krist 1995) to characterize the
nearly in-focus, undersampled HST PSF quite accurately (~1nm rms wfe)
- fourier transform relates image plane (PSF) to pupil plane (wavefront
error)
- iteratively fits wavefront surface with an orthogonal basis function,
specifically the Zernike polynomial series (Mahajan 1991)
where αnZn is the normalized Zernike polynomials & c is the solvedfor coefficients representing rms wavefront error in microns.
For n = 4 to 8, αnZn are given below:
α4Z4=
α5Z5=
α6Z6=
α7Z7=
α8Z8=
3.89(r2-0.55445)
2.31(r2cos(2θ))
2.31(r2sin(2θ))
8.33(r3-0.673796r)cosθ
8.33(r3-0.673796r)sinθ
focus
0 deg astigmatism
45 deg astigmatism
X coma
Y coma
HST’s Wavefront Sensing & Control Scheme
TIPS/JIM 21 Feb 2013
TEL Group
• Sensing (monthly phase retrieval)
- Phase retrieval performed on dedicated regular observations (~1 orbit/
month) with WFC3 & ACS.
- Cameras used have varied over the mission
- SIs have been set to be confocal within the errors during their
commissioning
• Control (periodic Secondary mirror despace adjustments)
- fits of monthly focus determinations distinguish long-term shrinkage
from ± ~3 micron temperature-driven “noise” (± 1.5 micron after
model subtraction)
- Control made when data trends beyond a threshold (tolerance has
varied over the mission, as guided by SI complement and desorption
rate). In recent years, ± ~3 microns (± 18 nm rms defocus). Aiming to
control tighter in the future for WFC3
Mission Lifetime Focus Maintenance
TIPS/JIM 21 Feb 2013
TEL Group
TIPS/JIM 21 Feb 2013
TEL Group
Most recent focus adjustment
&OCUS 4REND 3INCE $EC -IRROR -OVE
in July 2009 (SMOV4) predicted -2.4 +/- 1.4
microns of defocus January 24, 2012 for WFC3
• A +3.6 micron despace of the Secondary
mirror was commanded on January 24th.
Expected to put the Secondary +1.2 microns
from best focus for WFC3 UVIS (1.5 microns
from best focus for ACS WFC).
• Phase retrieval analysis of the standard
monitoring observations on January 26th. After
temperature model corrections, mean focus of
WFC3 over 1 orbit was found to be equivalent
of –0.68 +/-1.5 microns at the secondary mirror.
ACS was found to be +0.14 +/- 1.5 microns.
Not inconsistent with our expected state.
$AYS SINCE (34 DEPLOYMENT
›M
›M
›M
›M
›M
! C C UMULA TE D DE FOC US IN 3 - MIC RONS
• Linear fit to the observed data since refocusing
-IRROR -OVEMENT
%XPONENT &IT
%XPONENT &IT #ONT
"REATHING CORRECTED OTHER 3)S
"REATHING CORRECTED 7&# 56)3
• Subsequent monitoring data will better establish
OTA state.
Wavefront Sensing & Control: JWST vs. HST
TIPS/JIM 21 Feb 2013
TEL Group
• JWST wavefront evolution not expected to be dominated by long-term trend
• We are expecting to actively correct temperature-driven optical alignment
changes during science operations
• Sensing cadence every 2 days
• Control activities cadence unknown, but probably on order weeks to months
• Phase Retrieval much more complex than HST
- Like HST, operational sensing is science-image based, with Fourier
transforms relating image plane to the pupil plane
- Resulting phase map images of wavefront error are combined with a
“target” phase map to solve for the “pose” change required for each of
the 18 primary mirror segments
•
(a)
/
-r - -
4
07 ---/---- -
(b)
Fig. 14. (a) Predicted TBT wavefront error after fine-phasing (84 nm double-pass); (b) calculated PSF in single-pass; (c) calc
Modeled
typical JWST wavefront map & PSF
Measured HST wavefront map & modeled PSF