TIPS-JIM Meeting
17 May 2007, 10am, Auditorium
1.
INS Division News
Jerry Kriss
2.
WFC3 Ambient Calibration Results
Howard Bushouse
3.
Dither and Drizzling with WFPC2
Max Mutchler
4.
WFPC2 Closeout Plan
John Biretta
5.
Towards Creation of a JWST Astrometric Reference
Roeland van der Marel
Field: Calibration of HST/ACS Absolute Scale and Rotation
Next TIPS Meeting will be held on 21 June 2007.
TIPS-JIM Meeting
17 May 2007, 10am, Auditorium
1.
INS Division News
Jerry Kriss
2.
WFC3 Ambient Calibration Results
Howard Bushouse
3.
WFPC3 Drizzling Cookbook
Max Mutchler
4.
WFPC2 Closeout Plan
John Biretta
5.
Towards Creation of a JWST Astrometric Reference
Roeland van der Marel
Field: Calibration of HST/ACS Absolute Scale and Rotation
Next TIPS Meeting will be held on 21 June 2007.
WFC3
Ambient Calibration #2 Results
H. Bushouse
TIPS May 17, 2007
3
Ambient Cal #2 Overview
• WFC3 ambient calibration #2 ran from April 13-19, 2007
– WFC3 in the GSFC SSDIF clean room
– Latched into Radial Instrument Alignment Fixture (RIAF) and
“CASTLE” optical stimulus
– UVIS channel operations only (IR can’t be cooled sufficiently in
ambient)
– UVIS-2 detector with CCD’s at -54 C (vs. -83 C flight temp)
• Goals:
–
–
–
–
Verify re-integrated instrument operations
Verify successful lien closures
First look at UVIS-2 in (nearly) flight-like conditions
Verify operations of ground support equipment to be used in thermalvac #2
– Train and verify operations of support personnel
TIPS May 17, 2007
4
Instrument Preparations for
Ambient Cal #2
WFC3 closeout just prior to top cover installation
WFC3 top cover installed
WFC3 lift from Low Level Positioner (LLP)
WFC3 inserted into Radial Instrument
Alignment Fixture (RIAF)
TIPS May 17, 2007
5
Accomplishments
• ~30 SMSs, ~110 hours, 1525 images
–
–
–
–
–
–
–
–
–
–
–
–
Optical stimulus verification
UVIS-2 detector alignment check
System throughput with UVIS-2
Filter ghost check (lien related)
CCD electronic crosstalk check (lien related)
UVIS grism calibration: throughput, dispersion, and flat fields
Internal Calibration Subsystem check (lien related)
UVIS-2 bias, dark, readnoise, gain measurements
UV flats signal level check
Encircled energy check
CCD charge injection test
First test of CCD Extended Pixel Edge Response (EPER) mode
• Excellent job by I&T, Ops, CASTLE & Sci Cal teams
TIPS May 17, 2007
6
Thanks are due …
• IS’s
– S. Baggett, T. Brown, H. Bushouse, G. Hartig, A. Martel,
L. Petro, M. Robberto
• DA’s
– E. Barker, M. Cracraft, B. Hilbert, S. Holfeltz, D.
Karakla, J. Kim, K. Lindsay, D. Long, R. Lucas, J. Mack,
H. McLaughlin, C. Pavlovsky, B. Shaw, E. Smith, M.
Sosey
TIPS May 17, 2007
7
Instrument Science Reports
•
•
•
•
•
•
•
•
ISR 2007-15: WFC3 Ambient-2 Testing: UVIS Readnoise
S. Baggett 11 May 2007
ISR 2007-14: WFC3 Ambient-2 Testing: Calibration Subsystem Performance
S. Baggett 7 May 2007
ISR 2007-13: UVIS CCD EPER CTE measurements
M. Robberto 30 Apr 2007
ISR 2007-11: WFC3 Ambient-2 Testing: UVIS Gain Results
S. Baggett 27 Apr 2007
ISR 2007-10: WFC3 Ambient Testing: UVIS Dark Current Rate
B. Hilbert 26 Apr 2007
ISR 2007-09: UVIS Channel Filter Ghosts after Filter Replacement
T. Brown 26 Apr 2007
ISR 2007-08: Searching for Scattered Light on the WFC3 UVIS-2 Detector
T. Brown 24 Apr 2007
ISR 2007-07: WFC3 System Throughput on the UVIS Build 2 Detector
T. Brown 19 Apr 2007
TIPS May 17, 2007
8
System Throughput with UVIS-2
From STScI
Instrument
Science Report
WFC3-2007-07
(Tom Brown)
•
•
•
•
UVIS-2 QE better than predicted
Response of both CCDs comparable to UVIS-1 chip 1
UVIS-2 curves subject to small revision at proper operating temp
Optics throughput appears to have held up well since 2004 TV#1
TIPS May 17, 2007
9
UVIS Detector Throughput
Comparison
• UVIS-1 wins in blue; UVIS-2 wins in red
• F225W only important filter for which response differs by >10%
TIPS May 17, 2007
10
Excellent Read Noise w/ UVIS-2
• Like UVIS-1, UVIS-2 demonstrates “goal” level read noise
of 3 e- rms, vs. spec of 4; very important in UV
Gain = 1 e-/DN
UVIS-2 (ambient)
UVIS-1 (ambient)
Amp A
2.95
3.02
Amp B
2.94
2.97
Amp C
2.81
2.86
Amp D
2.90
2.99
Amp A
3.35
3.21
Amp B
3.34
3.25
Amp C
3.26
3.23
Amp D
3.53
3.28
Gain = 1.5 e-/DN
S. Baggett
TIPS May 17, 2007
11
UVIS Crosstalk Satisfactorily Resolved
• Extended source crosstalk (which could result from very
low level signals) is now undetectable (<0.1 e-)
– Combination of hardware change and timing pattern change
– New timing patterns show slightly improved read noise as well
(had been concerned they might have higher noise)
• No crosstalk in 2-amp readouts (i.e. from CCD to CCD)
• In 4-amp readout, small level of crosstalk remains from
saturated sources only
– New timing patterns slightly improve that level as well
– What remains is not a significant issue
preliminary analysis by S. Baggett
TIPS May 17, 2007
12
UVIS Crosstalk Satisfactorily Resolved (2)
Performance w/Hardware Rev &
New CCD Timing Patterns
Original Problem
window-CCD ghost
filter-CCD ghost
crosstal
k
source
stimulus artifacts
TIPS May 17, 2007
13
Internal Cal Subsystem Illumination
Improved
• Severe glints reduced; see F390M flats below
• Count rate specs achieved
• As shown previously w/UVIS-1, Deuterium flats much improved in
uniformity (2× vs. 5-10×)
F390M (inverse) flat before
F390M flat now
TIPS May 17, 2007
14
UVIS Grism Throughput Measured
UVIS grism
is WF/PC-1
spare; very
little
surviving
data
Data
provided to
SOC for ERS
planning
H. Bushouse
TIPS May 17, 2007
15
CCD Charge Injection Working Properly
Mean charge injection
signal level
~16,000 e-/pix
Noise in a single
column ~15 e- rms
Much greater CTE
benefit than from a
lamp pre-flash of
equivalent noise level
TIPS May 17, 2007
16
Improved Filter Ghost Performance
Confirmed
• Ambient cal measurements confirm the improved ghost performance of
the filters replaced in the SOFA
• Biggest success stories: F225W (<0.4% vs. 15%), F606W (elimination
of point-like ghosts), F280N (0.6% vs. 10-50% in ghost and horrific
scattered light flares)
Old
F225W
New
F225W
TIPS May 17, 2007
17
UVIS-2 Detector Alignment
• UVIS-2 aligned at Ball on 30 Jan ’07
– used new, direct, “through the window” alignment transfer from
UVIS-1 to UVIS-2
• UVIS-2 within tolerance in 4 degrees of freedom, out in 2
• Additional adjustment of tip/tilt is desirable, if misalignment is
confirmed in upcoming TV#2 testing
TIPS May 17, 2007
18
UVIS-2 Misalignment Consequences
• At best focus, the performance degradation due to the current
level of tip/tilt misalignment is negligible, however …
• OTA breathing exacerbates the misalignment, causing a small
loss of performance over field, especially at short wavelengths
– Slight EE loss in small apertures
– PSF change (due to field dependent astigmatism inherent in optical
design)
TIPS May 17, 2007
19
What’s Next?
• IR-1 detector package installation
– Received at GSFC yesterday (5/16); installation today
• System Level Thermal-Vac #2
– WFC3, with UVIS-2 and IR-1, into SES chamber ~5/29
– Ambient system functionals and alignment check ~6/1-6/5
– Vacuum testing for following ~75 days
• 24/7 support from STScI IS’s, DA’s, and Ops
– Proto-flight qualification of instrument
•
•
•
•
Thermal cycling
Performance of all thermal systems
Full science calibration of UVIS and IR channels
CEI specifications verification
TIPS May 17, 2007
20
IR FPA QEs
100
Quantum Efficiency (%)
90
80
70
IR3
60
50
IR1
40
IR2
30
20
10
IR Channel Wavelength Range
0
200
400
600
800
1000
1200
1400
1600
1800
Wavelength (nm)
FPA 64
FPA 129
TIPS May 17, 2007
FPA 150
FPA 160
21
Backup slides
TIPS May 17, 2007
22
UVIS-2 Misalignment EE Penalty
OTA SM
despace:
+3µ
Nom
-3µ
Detector
alignment:
Optimal
Optimal
As-is
As-is
TIPS May 17, 2007
23
PSF Change with OTA Breathing
UVIS-2 CASTLE 633nm UV-11
-3µ
0µ
TIPS May 17, 2007
+3µ
24
FPA 160 Dark Current
% of Pixels Above Dark Rate
100
90
80
70
60
50
40
30
20
10
0
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
-
Dark Current (e /sec/pix)
FPA 64
FPA 129
TIPS May 17, 2007
FPA 150
FPA 160
25
1
FPA 160 Persistence
TIPS May 17, 2007
26
FPA 160 Read Noise
CDS Noise (e- rms)
FPA 64 (IR2)
24
FPA 129 (IR1)
22
FPA 150 (IR3)
24
FPA 160
25
FPA 165
24
TIPS May 17, 2007
27
FPA 165 QE
TIPS May 17, 2007
28
SMGT preparations
•
Revised SMGT Part 2 SMS
–
–
–
–
•
Added UVIS Anneal exposures
Revised management of tungsten & D2 lamps
Corrected UVIS quad filter commanding
Duration of SMS is 20.5 hours
Delivered SMS 3/30/2007 for test
– SMS ran successfully in VSTIF 4/23/2007
– Science data ftp’ed to STScI for OPUS processing
•
Revised SOGS Support Schedules for SM4 Functional Test
– Science data from Early VEST test ftp’ed to STScI for OPUS processing
•
Prepared OPUS for processing of VSTIF and Early VEST data
– Anomalies identified from February VSTIF run corrected
– Software testing and delivery complete by 5/2/2007
TIPS May 17, 2007
29
SMGT Part 2 SMS Content
TIPS May 17, 2007
30
Preparation of
SMGT Part 2 SMS
Anomaly
Subsystem
Assignee
Status
Update UVIS & IR filters (F588N⇒F200LP &
F098W⇒F140W)
Errors in SIAF aperture specifications
APT, IM
ESS
Closed
TRANS
OBS/TEL
Closed
Incorrect reporting: errors for NICMOS; CRSPLIT exp.
ANNEAL not used
Detector temperature set-points raised for
ambient
Mosaic dithers generate pointing warnings
Tungsten lamp on during readouts
Patch SMS for CS 3.0 D limits
Error inhibiting 6-stage TEC for ambient tests
APT
OED
Closed
N/A
IM
INS/WFC3
OED
Closed
Closed
APT
TRANS
IM
IM
OED
INS/WFC3
OED
OED
Closed
Closed
Closed
Closed
TIPS May 17, 2007
31
SMGT VSTIF Results
Anomaly
Subsystem
Assignee
Status
UVIS full-frame exposures fail in Generic Conversion
OPUS/GC
DPT
Closed
Errors in IR dark reference file keyword values
CDBS
INS/WFC3 Closed
Incorrect IR dark reference file selection for subarrays
CDBS
INS/WFC3 Closed
IR subarray format not listed in science image headers
KWDB
DPT
Closed
Incorrect WFC3 SIAF values
SIAF
OBS/TEL Closed
Incorrect CCD amp selection for UVIS Quad filters
Commanding
SCSB
Closed
Inadequate representation of UVIS Quad filters in use
OPUS/GC INS/WFC3 Open
Generic Conversion still using old IR readout times
OPUS/GC
DPT
Closed
Incorrect PRIMESI keyword values
OPUS/GC
DPT
Closed
Incorrect PHOTMODE keyword values
CALWF3
INS/WFC3 Closed
CALWF3 IR dark frame selection enhancement
CALWF3
INS/WFC3 Closed
Updated IR dark calibration reference files needed
CDBS
INS/WFC3 Closed
TIPS May 17, 2007
32
TIPS-JIM Meeting
17 May 2007, 10am, Auditorium
1.
INS Division News
Jerry Kriss
2.
WFC3 Ambient Calibration Results
Howard Bushouse
3.
WFPC3 Drizzling Cookbook
Max Mutchler
4.
WFPC2 Closeout Plan
John Biretta
5.
Towards Creation of a JWST Astrometric Reference
Roeland van der Marel
Field: Calibration of HST/ACS Absolute Scale and Rotation
Next TIPS Meeting will be held on 21 June 2007.
Dithering and Drizzling with WFPC2
Max Mutchler
TIPS Meeting
17 May 2007
NGC 2440
Overview
• Recently expanded online suite of WFPC2
dither and mosaic pointing patterns
• The Dither Handbook (2002): drizzle, with
many WFPC2 examples
• New online drizzling “cookbook”: PyDrizzle
and MultiDrizzle, with WFPC2 examples
http://www.stsci.edu/hst/wfpc2/analysis/drizzle.html
Expanded suite of suggested
pointing patterns for WFPC2
http://www.stsci.edu/hst/wfpc2/analysis/wfpc2_patterns.html
Small-scale dithers
Large-scale mosaics
The online
cookbooks
Drizzling cookbook format:
keep it simple and pragmatic
• Set of cookbooks for various pointing strategies and target
placements (PC or WF chip/s)
• Which archive files to retrieve (c0h, c1h)
• Setting up a uref directory with distortion correction files
(IDCTAB and OFFTAB)
• Some tangential issues: image registration; WF4 bias
correction…
• PyDrizzle and MultiDrizzle parameters (reasonable first
pass)
• Inspecting output, iterating, optimizing: what to look for,
which parameters to experiment with
• Contact the Help Desk with questions
Some recent well-documented
examples of WFPC2 drizzling:
http://archive.stsci.edu/prepds/heritage/
Jupiter
NGC 2440
Whirlpool Galaxy M51
Ring Nebula M57
WFPC2 mosaic examples
(coming soon…)
NGC 2440 at 0.10 arcsec/pixel (detector scale)
http://heritage.stsci.edu/2007/09/supplemental.html
NGC 2440 at 0.06 arcsec/pixel (sub-sampling scale)
http://heritage.stsci.edu/2007/09/supplemental.html
TIPS-JIM Meeting
17 May 2007, 10am, Auditorium
1.
INS Division News
Jerry Kriss
2.
WFC3 Ambient Calibration Results
Howard Bushouse
3.
WFPC3 Drizzling Cookbook
Max Mutchler
4.
WFPC2 Closeout Plan
John Biretta
5.
Towards Creation of a JWST Astrometric Reference
Roeland van der Marel
Field: Calibration of HST/ACS Absolute Scale and Rotation
Next TIPS Meeting will be held on 21 June 2007.
WFPC2 Closeout Plan
John Biretta
17 May 2007
46
WFPC2 Closeout Plan
• WFPC2
–
–
–
–
15 yrs on-board HST
30% of HST science exposures
Important part of HST legacy
De-orbit in T-16 months…..
• Closeout Plan for remaining work…
–
–
–
–
–
–
Final on-orbit calibrations
Calibration projects / enhancements
Archive enhancements
Final documentation
Cycle 16 GO support
Priorities, staffing, etc.
47
Closeout Plan “draft” on WFPC2 internal page:
www.stsci.edu/hst/wfpc2/internal
48
WFPC2 Closeout Plan
• Solicit comments & suggestions…
–
–
–
–
–
Missing on-orbit calibrations?
Areas needing better calibration?
Projects to improve calibration?
Different priorities or goals?
Other concerns?
• Feedback especially useful in next month as
we finalize plans and decide priorities
www.stsci.edu/hst/wfpc2/internal
49
TIPS-JIM Meeting
17 May 2007, 10am, Auditorium
1.
INS Division News
Jerry Kriss
2.
WFC3 Ambient Calibration Results
Howard Bushouse
3.
WFPC3 Drizzling Cookbook
Max Mutchler
4.
WFPC2 Closeout Plan
John Biretta
5.
Towards Creation of a JWST Astrometric Reference
Roeland van der Marel
Field: Calibration of HST/ACS Absolute Scale and Rotation
Next TIPS Meeting will be held on 21 June 2007.
Towards Creation of a JWST
Astrometric Reference Field:
Calibration of HST/ACS
Absolute Scale and Rotation
Roeland
van der Marel
Jay Anderson, Colin Cox, Vera Kozhurina-Platais, Matt Lallo, Ed Nelan
Astrometric Calibration

2 Translations (x, y)

JWST: Guide stars + Target acquisitions

Scale
Rotation
2 Skew terms (Δscale and Δrotation)

Higher-order distortions



6 linear
parameters
JWST: Observations of Astrometric Reference Field
JWST Astrometric Reference Field

Self-calibration of astrometry using JWST
observations not feasible



Requires observations at multiple ORIENTs (interval of
months)
Observatory characteristics might change between
such observations (WFS&C every 2 weeks)
Alternative: observe astrometric reference field



In JWST Continuous Viewing Zone
Adequate stellar density
Low proper motions
Large
Magellanic
Cloud (LMC)
JWST Astrometric Requirements

Mission Requirement (MR-120)


After calibration, the field distortion uncertainty … shall not
exceed 5 mas, 1-sigma per axis
Motivation: need to prepare NIRSpec observations
based on NIRCam images

Accurate higher-order distortion correction
 LMC field observed with HST/ACS mid 2006 (Diaz-Miller et al.)


Calibration to same relative scale
Desire: also accurate absolute scale + rotation


Use of coordinates from other observatories
Accurate calibration of focal plane orientation of
instruments (w.r.t. star trackers)
 Calibrate absolute scale and rotation of HST/ACS (this talk)
HST/ACS Astrometric Calibration

2 Translations





Not relevant here
Scale
Desired accuracy ~ 5 x 10-5
(corresponds to 5 mas
Rotation
over 1-2 arcmin FOV)
2 Skew terms
Higher-order distortions


Previously calibrated by Anderson
No known time-dependence
Calibration of HST/ACS
scale and rotation

Observations of a field with good astrometry
 M35 (HST/FGS calibration field)




Good relative astrometry (< 1 mas)
Good proper motions (< 0.2 mas/yr)
Poor absolute astrometry
Approach


Build M35 catalog with good absolute astrometry
Observe M35 stars in this catalog with HST/ACS
Building an M35 Catalog



Start with M35 FGS catalog in V2-V3 HST focal
plane (92 stars with proper motions from FGS
Science Team)
Cross-identify these stars with USNO UCAC2 on
ICRS
Match stars using linear transformations



RMS 21 mas per coordinate
Fractional scale uncertainty 0.6 x 10-5
Rotation uncertainty 0.6 x 10-5
HST/ACS observations of M35







10 stars
V magnitude = 8 - 13
WFC , F658N
4 dither positions
2 sec exposures
Dec 2006
Measure positions and correct for higher-order
distortions using Anderson software

(x,y) on Distortion-Corrected Frame (DCF)
Scale and Rotation of DCF

Match stars using linear transformations with FGS/
UCAC2 Catalog




RMS < 2 mas per coordinate
Fractional scale uncertainty 0.6 x 10-5
Rotation uncertainty 0.6 x 10-5
Some subtle corrections required


Differential velocity aberration affects scale
Sky looks distorted when projected on a plane


Orientation at ACS/WFC is not the same as at the V1 axis
Final results


s = 0.0497248 arcsec/pixel
b = 177.7612 degrees
Time Variation of HST/ACS
Linear Distortion Terms
rotation
scale

5 years of repeated
47 Tuc imaging
(Anderson 2007)



Scale quite stable
Rotation shows ~0.003
deg non-repeatability
Skew varies linearly with
time

M35
Confirmed by M35 data
Δrotation
Δscale
Checks Performed to Assess
Systematic Errors






Consistency between UCAC2 to GSC2
Residual skew terms between catalogs
Influence of CTE on ACS results
Consistency between different ACS filters
Consistency with past calibrations and Multidrizzle
output
Consistency with results implied by analysis of
telescope slews (POSTARGs)
Final Result

Formalism to correct any ACS/WFC dataset
to absolute coordinates (modulo translations)
with [accuracy in units of 10-5]




Known Scale to 1.1 (random) and 0.6 (syst)
Known Rotation to 4.8 (random) and 3.9 (syst)
No residual skew to 0.3 (random) and 1.3 (syst)
Should be sufficient for JWST purposes
TIPS-JIM Meeting
17 May 2007, 10am, Auditorium
1.
INS Division News
Jerry Kriss
2.
WFC3 Ambient Calibration Results
Howard Bushouse
3.
WFPC3 Drizzling Cookbook
Max Mutchler
4.
WFPC2 Closeout Plan
John Biretta
5.
Towards Creation of a JWST Astrometric Reference
Roeland van der Marel
Field: Calibration of HST/ACS Absolute Scale and Rotation
Next TIPS Meeting will be held on 21 June 2007.