TIPS-JIM Meeting
16 March 2006, 10am, Auditorium
1.
A Novel near-UV/Visible Balloon Payload
Dr. Charles Joseph,
Rutgers University
2.
JWST/NIRSpec Status and PDR Results
Jeff Valenti
3.
Characterization of Faint Compression
Eddie Bergeron
Artifacts, Bias Residuals, Optical Glints and
Electronic Crosstalk Ghosts in Deep ACS Imaging
Next TIPS Meeting will be held on 18 May 2006.
Why A Long-Duration Balloon?
HAWK
Image Quality Comparison
Alt.
Aperture
r0 (m)
FWHM(")
θ0 (")
τ0 (sec)
4 km
CFHT 3.8m
0.18
0.7
3
0.0036
35 km
2.4 m
~250
0.048
~600
~5
35km
10 m
~250
0.012
~600
~5
Atmospheric Parameters Comparison
h (km)
P (mbars)
T (K)
ρ (gm m-3)
H2O Vapor (gm m-3)
4
680
253
937
0.68
35
4.7
222
7.4
0.00011
Data from Ford et al. 2000
Presented by
Chuck Joseph
26-March-06
Hierarchical Assembly through
Wide-field Kinematics
Novel HAWK Telescope Optical Design
System is fully steerable over 0.5° x 1.5° using only tip/tilt of a 10 cm flat mirror
0.5° x 1.5° field of regard
2.2 arcmin IFOV
Primary mirror
1.8 m diameter
f/2.7 (from MMT)
Pickoff mirror
30 x 64 cm flat
near intermediate focus
Secondary mirror
35 cm diameter
(Used slightly off axis)
Tertiary mirror
0.5 m x 1.1 m
off axis asphere
(long direction is out of the page)
Design by CoI Jim Burge
Steering mirror
10 cm flat
5° x 15° range of motion
at exit pupil
Focal plane
f/27 system
4.2 arcsec/mm plate scale
(2k x 2k x 16 µm CCD shown here)
Excellent performance
across the field
HAWK
Nominally designed so that rms
wavefront error RMSWE is limited
to 20 nm.
Low imaging distortion
(4% max at corners of field)
RMS Wave Front Error in Waves
0.050
0.000
0.000
0.75
-X Field
(degrees)
HAWK
Proposed
HAWK
LDB Mission
Hierarchical Assembly through
Wide-field Kinematics
---The Big Bang ---
A consistent picture of the
evolution of the Universe
from the Big Bang to the
present is emerging. Some
data, however, suggest
galaxies may not fit this
model!
(15 Billion Yrs Ago. z > 100)
The Unobserved Realm
To Be Explored by JWST
First Star Formation
First Galaxy Structures
From the Early Universe
(11 Billion Yrs Ago; z ~ 1.5)
Galaxies were less well organized
Galaxy Evolution
To be observed by HAWK
Merging Galaxies
Payload to be
designed & built
at Rutgers U.
Hierarchical Assembly through
Wide-field Kinematics
HDF
HDF Redshift Catalog
Distance (Mpc x 105)
HAWK
0.7
1.2
Mission Objectives:
Graphics Credit: Fanning Software Consulting
 Study all motions in a
10 Mpc3 Volume!
 Determine luminous +
dark matter content as a
function of internal
radius and redshift.
 Measure empirically
how galaxies evolve from
an early epoch. !
(Model independent.)
HAWK will pick up 100x more than HST!
Observing Galaxies as a Function of Z
Emission Map
z = 1.35
HAWK Balloon
Mission Objective:
Measure luminous and
dark matter in galaxies
Emission Map
z = 0.75
Emission Map
z = 0.35
e263g14
Rotation Curves
Velocity Map
z = 0.75
Velocity Map
z = 1.35
Velocity Map
z = 0.35
HAWK LDB Balloon -- Can’t do Imaging Spectroscopy
with Large Ground-based Telescopes with AO
FOV on a
10 m with AO
With AO
HAWK FOV
PSF Comparisons
Bottom: 10 m good seeing
Top: 10 m with AO
HDF North
Ground-IR have Bad
Thermal Backgrounds!
HAWK spatial resolution = 0.07″
Good Seeing
Without AO
KITE
Kinematical
Imaging
Trailblazer
Experiment
Near-UV EBCCD
Electron-Bombarded CCD
Weight: 4 kg
(2 kg Possible)
c/f MAMA: 10 kg
Swallow-tail Kite by D.A. Rintoul, USGS
25% QE – Solar Blind
(50% Possible) c/f MAMA 10%
c/f WFPC2 system efficiency 0.25%
5.6x of GALEX with 0.75 m telescope
TIPS-JIM Meeting
16 March 2006, 10am, Auditorium
1.
A Novel near-UV/Visible Balloon Payload
Dr. Charles Joseph,
Rutgers University
2.
JWST/NIRSpec Status and PDR Results
Jeff Valenti
3.
Characterization of Faint Compression
Eddie Bergeron
Artifacts, Bias Residuals, Optical Glints and
Electronic Crosstalk Ghosts in Deep ACS Imaging
Next TIPS Meeting will be held on 18 May 2006.
NIRSpec Status and PDR Results
Jeff Valenti & Mike Regan
2006 March 16
TIPS/JIM
Light Path
PDR Objectives



Assess compliance with requirements
Assess NIRSpec system specifications
Assess external interface definitions





Integrated Science Instrument Module
Microshutter Array
Detector Subsystem
Assess predicted NIRSpec performance
Assess cost, schedule, and risk estimates
PDR Format

Board



Technical Panels






Led by ESA with NASA participation
Co-chaired by NASA Independent Review Office
System
Structure, thermal, and mechanisms
Optics
Electrical and software
Product Assurance
Programmatic Panel
PDR Timeline




Dec 1 Documents delivered
Dec 2 Kick-off meeting held
… Panel meetings …
Jan 6 Panel chairs met
“Review Item Dispositions” submitted
Jan 31-Feb 2 Co-location
 ESA/Industry
 ESA/Instrument Science Team
Feb 9 Panel chairs reported to board
Feb 15 Board met




PDR Verdict

NIRSpec PASSED its PDR!
PDR Major Findings








Microshutter technology is a risk
Electrostatic discharge is a risk
Create stray light control plan
Include detector in EMC control plan
Cool light sources used in ground tests
Prevent contamination by water
Manage target acquisition interfaces
Test cold after observatory integration
No Schedule Change


JWST launch date slipped to June 2013
NIRSpec delivery date is unchanged




Necessary to control ESA costs
Requires timely definition of interfaces
Requires timely delivery of subsystems
NASA funding ISIM to support schedule
Microshutter Update

Technology demonstration tests








Lifetime test: <5% shutters fail after 105 cycles
Acoustic test: <1% shutters fail
Vibration test: <1% shutters fail
Radiation test: <1% shutters fail
Open/closed contrast: >2000
EMC/EMI test
Demonstrate ability to plug shutters in lab
Stiction issue


0.5% shutter stuck open after 105 cycles
Heating to 300 K causes shutter release
Rogue Path Update
Unbaffled telescope
Sky skirts FSM and
illuminates POM
NIRSpec wants 9 mm
increase in FSM mask
NIRCam coronagraph
blocked by >6 mm
Outer edge of
FSM mask
Inner edge of
NIRSpec mask
Q1 Q2
Orders
of
Magnitude
in
Scale
10×
Q3 Q4
10×
4×365×171
250K Shutters
10×
Plate Scale Changes
We must position
targets in shutters
Allocate 5 mas for
plate scale changes
Corresponds to 0.01%
change in focal length
Rephase primary as
often as once a week
TIPS-JIM Meeting
16 March 2006, 10am, Auditorium
1.
A Novel near-UV/Visible Balloon Payload
Dr. Charles Joseph,
Rutgers University
2.
JWST/NIRSpec Status and PDR Results
Jeff Valenti
3.
Characterization of Faint Compression
Eddie Bergeron
Artifacts, Bias Residuals, Optical Glints and
Electronic Crosstalk Ghosts in Deep ACS Imaging
Next TIPS Meeting will be held on 18 May 2006.
Horizontal Striping
Vertical Striping
Superdark has bias “hot column” residuals in it. These
don’t scale linearly with exposure time and print onto
science data.
Superbias images below with hot pixels removed, then smoothed to show structure
bias stripes removed
with bias stripes
Pipeline bi-weekly superdarks show similar bias striping
Other macro-scale structures in the dark are likely amplifier bias shape
differences between the 1000s dark exposure and the 0s bias subtracted from it.
The 1200s science exposures will have similar (but not exactly the same)
residuals.
Low/hi corners and
vertical/horizontal
gradients across the
quads are most likely
bias, not dark current
Glint
(internal optical reflection)
Optical glint, possibly from an off-chip source
crosses the field diagonally. Would like to
characterize its behaviour (motion and
intensity) so it can be subtracted from the data
before drizzling.
The glint in each chip was
measured at 3 points along its
length to get its slope and
amplitude
Fitting lines to the glint across both chips revealed that
its is pivoting about a point near the upper left edge of
chip2.
A model glint image was
build by shifting and
rotating all the images to
the same glint
orientation and filtering
sources. This model,
masked to minimum
extent then rotated,
shifted and scaled, was
then subtracted from
each input image before
drizzling.
Chip 2
Chip 1
Close-up of Chip 1 Glint
Residual “sky” Subtraction
Since many of the residual
bias/dark structures
discussed previously have
not been corrected by the
reference files, a catch-all
sigma-clipped average,
source-masked sky made
from all of the input images
is subtracted from each
image before drizzling.
Some glint residual is visible
here and that will
oversubtract from the data,
leaving a faint dark residual
in the final image.
This is an image of all the systematic noise
remaining after the pipeline calibration
Amplifier Ringing?
Moderately bright star (but unsaturated in 1200s) leaves a long
decaying, very faint trail in the serial read direction. The decay is
slow enough to wrap around to the next row. This is similar to
behaviours seen in WFPC2 and NICMOS, but much, much fainter.
Its likely this is
present for all
bright, sharp
sources, but
only visible
above the noise
with deep
imaging like
UDF
Correctable with a sum of exponentials in the serial read direction
Electronic Crosstalk Ghosts
Sources produce dark ghosts of themselves in the opposite quadrant
and even in the quads of the other WFC CCDs. This is some form of
electronic crosstalk (see ACS ISR 4-12, 4-13, Giavalisco 2004 for details).
Even in this GAIN=2 data, the ghosts are quite prominent. In the
drizzled z-band image, the ghosts are smeared by the dithering.
Due to the orientations of the readout directions of the 4 WFC
quadrants, the ghosts move in the opposite direction of the sources
in the serial readout direction (X), but they move together in the
parallel readout direction (Y).
Ghosts and their sources
Serial
Parallel
C
Serial
Parallel
A
Serial
The same logic
applies to all 4
quads.
D
Y
Parallel
If a source in
quad D moves in
+X,+Y, its ghost
in quad C moves
in -X,+Y.
Chip2
Parallel
ACS WFC
readout
orientations.
Sources and
ghosts follow the
arrows.
B
Serial
Chip1
X
Flip -X,Y then copy
Serial
Parallel
C
D
Y
A
Serial
Parallel
Parallel
Three
permutations -3
drizzles - gives
you all 12 ghost
quads. (3 ghosts
per 4 source
quads)
Serial
Parallel
Use a trick to
make drizzled
images of the
ghosts: Flip the
quads in
appropriate
directions, then
drizzle!
Example for l-r interchip permutation
B
Serial
Flip -X,Y then copy
X
Once you have high S/N images of ghosts you can either
subtract the image directly, or try to build a model of the ghost
behavior as a function of source - that’s the next step…
Side-by-Side Comparison
Original
(same stretch)
Cleaned
Still to do: E-ghosts, better glint subtraction, amp ringing correction
end transmission
TIPS-JIM Meeting
16 March 2006, 10am, Auditorium
1.
A Novel near-UV/Visible Balloon Payload
Dr. Charles Joseph,
Rutgers University
2.
JWST/NIRSpec Status and PDR Results
Jeff Valenti
3.
Characterization of Faint Compression
Eddie Bergeron
Artifacts, Bias Residuals, Optical Glints and
Electronic Crosstalk Ghosts in Deep ACS Imaging
Next TIPS Meeting will be held on 18 May 2006.