TIPS/JIM
February 21, 2008
Agenda:
INS Division News (Jerry Kriss)
An Unexpected Hysteresis Effect Seen in Hawaii-2RG Detectors (Jay
Anderson)
One-Gyro Science On-Orbit Test & Kalman Filter Sunpoint Safemode
Test (Merle Reinhart)
WFPC2 1-Gyro Test Results (Matt McMaster)
One-Gyro Operations FGS Observations (Ed Nelan)
Next TIPS/JIM: March 20, 2008
1
Instruments Division News
02/21/2008
•
•
•
•
•
•
Congratulations to our new DA Group Lead, Francesca Boffi, who officially took up
her new job on Monday, February 4.
Welcome to these new instrument scientists who just officially joined our staff this
week:
o André Martel, who started on Monday, joins the WFC3 team full time.
o David Golimowski also started Monday, and he joins the ACS+WFPC2
team full time. For the time being, André and David will remain in their
JHU offices.
o Susana Deustua joined the WFC3 team on Monday. Susana is in S420D.
We are continuing to add office space on the 4th floor.
o S412, Marc Postman’s office, was divided into two offices..
o S421 and S422A, currently housing Megan Sosey, Sherie Holfeltz, Ed
Smith, and Eddie Bergeron, will be rearranged into three, two-person,
standard-size offices.
o Ed and Eddie will be moving into the “L” of N407.
o Nor Pizkal will move into the “L” of S406.
o Megan and Sherie will move into Nor’s old office, N404.
HST news:
o New official launch date for SM4 is Aug. 28. Remember to get your
requests for launch invitations to Danny Golombek.
o Two weeks to go before the CP17 deadline!
o WFC3 thermal vac 3 is starting this week.
JWST news:
o The Operations Scripts Subsystem PDR on January 22-23 at STScI was
very successful.
o Proposal and Planning System SRR, this past week on February 19-20 at
STScI, was also quite successful.
o Lots of effort is going into the “rephasing” proposal, expected to be
completed by the end of March.
o Training is underway for the upcoming thermal vacuum test of the MIRI
“Verification Model”, which will take place this spring at Rutherford
Appleton Labs.
o JWST Mission PDR is coming up on March 31 to April 4, followed in a
few weeks by the Non-Advocate Review (NAR). This is the official
“gate” for having JWST officially approved.
An update on the INS Diversity, Culture and Respect Working Group:
o I presented the list of recommendations and our current implementation
status to the Directorate this past Monday.
o Kevin Lindsey will issue his comprehensive final report by the end of
February.
•
o We have been discussing the group’s recommendations more widely
throughout the division within individual teams and groups to develop a
consensus for implementation. Please continue to read and consider the
recommendations and offer feedback to Kevin or your managers.
The next INS pizza lunch is next week, February 28, in the Boardroom from 12:001:30. If you plan to attend, please give $5 to Debbie Brenner by 5 pm next
Wednesday. Thanks!
o Volunteers to coordinate future events would be welcome!
TIPS/JIM
February 21, 2008
Agenda:
INS Division News (Jerry Kriss)
An Unexpected Hysteresis Effect Seen in Hawaii-2RG Detectors (Jay
Anderson)
One-Gyro Science On-Orbit Test & Kalman Filter Sunpoint Safemode
Test (Merle Reinhart)
WFPC2 1-Gyro Test Results (Matt McMaster)
One-Gyro Operations FGS Observations (Ed Nelan)
Next TIPS/JIM: March 20, 2008
1
An Unexpected Hysteresis Effect
Seen in Hawaii-2RG Detectors
•
Background
–
Distortion calibration important for JWST
•
•
•
Coronagraphy, MSA, slits
Self-calibration will be difficult
ACS field observed in 2006
–
–
–
–
In LMC, in JWST’s CVZ
5′×5′: big enough for all detectors
Good density of stars
Many well-measured stars
•
–
More than 100,000 good to 1 mas
Good, but…
1) Not big enough for cross-calibration
2) No IR color information
Jay Anderson --- TIPS
Feb 21, 2008
17"
J1
Ground-based Observations
• HAWK-I: new IR camera
–
–
–
–
Being commissioned on VLT at Paranal
7.5′×7.5′ FOV
2×2 mosaic of 2048×2048 NIR detectors
“Active optics”
• Luigi Bedin (STScI) observed the JWST field
– For them: exquisite distortion solution
– For us: IR photometry & larger field
• We got an additional benefit…
Jay Anderson --- TIPS
Feb 21, 2008
J2
HAWK-I distortion:
Raw residuals
One chip
After global
correction:
Δx
Δx
Δx
Δx
Δx
Δx
Δx
Δx
Jay Anderson --- TIPS
Feb 21, 2008
J3
Periodic
residuals
Phase Diagram
Phase Diagram
•Same
throughout
detector
•Periodogram
•Square wave
removes
periodic
signature
Jay Anderson --- TIPS
Feb 21, 2008
J4
Why do we care?
• Rockwell Scientific
HAWAII-2RG
– Prototype for JWST!
• Very important to
understand the source
WFC FLAT FIELDS
– Geometric, like HST?
• WFPC2’s 34-row effect
• ACS/WFC’s 68-column
effect
– Check flat fields
HAWK-I
• No evidence
Jay Anderson --- TIPS
Feb 21, 2008
J5
Why do we care?
32 amplifiers →
AMP#0
AMP#1
AMP#2
AMP#3
AMP#4
• Rockwell Scientific
HAWAII 2RG
– Prototype for JWST!
• Very important to
understand the source
– Geometric? No!
– Readout artifact?
All CRs
• HAWK-I Readout
• CTE-like hysteresis
Even Amps
Odd Amps
– PSF asymmetry?
– Look at CRs…
• Likely cause
inter-pixel capacitance
– pixel dwell time
Jay Anderson --- TIPS
Feb 21, 2008
J6
Possible Implications
for JWST
• JWST will have four amplifiers
– four 512-pixel zones
– Not clear if effect comes before
or after the amplifiers… Really a problem?
• How to deal with hysteresis?
– Mild deconvolution? (will amplify noise)
– Leave in, but model
• Similar to the inter-pixel capacitance
• Effective PSF will treat it implicitly as Π(Δx,Δy)
• Need to study impact on:
– subarray mode, guider, spectra, dithering, noise model
• Early NIRCam/U.AZ tests
– encouraging!
Jay Anderson --- TIPS
Feb 21, 2008
J7
TIPS/JIM
February 21, 2008
Agenda:
INS Division News (Jerry Kriss)
An Unexpected Hysteresis Effect Seen in Hawaii-2RG Detectors (Jay
Anderson)
One-Gyro Science On-Orbit Test & Kalman Filter Sunpoint Safemode
Test (Merle Reinhart)
WFPC2 1-Gyro Test Results (Matt McMaster)
One-Gyro Operations FGS Observations (Ed Nelan)
Next TIPS/JIM: March 20, 2008
1
TIPS
Feb 21, 2008
One-Gyro Science On-Orbit Test
&
Kalman Filter Sunpoint Safemode Test
Merle Reinhart
1
TIPS
What is 1-Gyro Science Mode?
•
•
•
Feb 21, 2008
In this mode, only 1 gyro is available for rate sensing
Now have a gyro-less plane rather than just a gyro-less axis as 2gyro mode
Has three main sub-modes like 2-gyro mode
– M1G - Attitude errors can be as large as 9 degrees
» Sensors are:
• The Gyro
• Magnetic Sensing System
• Coarse Sun Sensor
» A Kalman Filter which is an attitude predictor-corrector is used to
combine all the sensors along with aerodynamic and gravity gradient
torque compensations to provide for a 3-axis stabilized control.
– T1G - Attitude errors can be as large as a few tens of arcseconds
» Sensors are:
• The Gyro
• Fixed Head Star Trackers
» Perform OnBoard Attitude Determinations to reduce the attitude errors
– F1G - Attitude errors typical at the catalog error of about 0.3 arcseconds
» Sensors are:
• The Gyro
• The Dominant FGS
2
TIPS
Why 1-Gyro Science Mode?
Feb 21, 2008
• SM4 is only 27 weeks away. Why are we still talking about 1Gyro mode?
•
Gyro run times (21-Feb-2008)
–
–
–
–
–
–
–
•
G1 49850 hours (5.69 yrs)
- operational, powered
G2 57411 hours (6.55 yrs)
- failed 31-Aug-2007, flex lead
G3 33197 hours (3.79 yrs)
- failed 29-Apr-2003, rotor restriction
G4 53505 hours (6.10 yrs)
- operational, turned off 28-Aug-2005
G5 16126 hours (1.84 yrs)
- failed 28-Apr-2001, rotor restriction
G6 16723 hours (1.91 yrs)
- operational, powered
Mean time to flex lead failures is 41800 (4.77 yrs) hours
All 6 gyros (3 rate sensing units - RSUs) are slated to be replaced
during SM4 in EVA2
3
TIPS
Feb 21, 2008
Gyro Lifetime Estimates
•
Chart below shows approximate gyro failure probabilities assuming a gyro failure in July
2007 (close to time of Gyro #2 failure)
1
0.9
SM4
0.8
Jul-2007
0.7
Availability
0.6
Feb-2011
Jan-2009
0.5
0.4
0.3
May-2008
0.2
0.1
0
Feb-2007
Feb-2008
Feb-2009
Feb-2010
Feb-2011
Feb-2012
Feb-2013
Feb-2014
Feb-2015
Tim e (calendar date)
1 or more operating gy ros
2 or more operating gy ros
3 gy ros (2 operating, 1 in-res erv e)
Predictions from Helen Wong (Aerospace Corp)
as communicated to Art Whipple (HSTP)
4
Feb-2016
Feb-2017
TIPS
The OGS On-Orbit Test
•
Visits from 4 proposals
–
–
–
–
•
•
•
11077 - WFPC2
11078 - Astrometry
11497 - Mars
11345 - PCS Tests
5
OGS Test was a full 2 days
KFSP Test was 18 hours
Total time 2d 21h
Feb 21, 2008
TIPS
OGS High Level Results
Feb 21, 2008
• Completed OGS on orbit testing
– Assessment indicates performance as expected
• 60/60 OBADs with nominal performance
– Max correction for 1st OBAD was 2.44 degrees and 2nd OBAD
was 38 arcsec
• 18/18 guide star acquisitions/reacquisitions were successful
– Astrometry, 2-GS with re-acq, 1-GS with re-acq, K13 variations,
Mars
6
TIPS
Feb 21, 2008
F1G OOT Performance
•
•
Jitter computed over entire guiding interval with merged data
Values shown are the 60 second root sum squared of the V2 and V3 standard
deviations of position path
Data Start
Time
FGSs In
Use
Dominant mV,
catalog
Max Jitter,
DVTHEP, mas
Mean Jitter,
DVTHEP, mas
Min Jitter,
DVTHEP, mas
Comments
29/17:03
2,3,3
13.124
7.0
5.8
5.0
Astrometry
29/18:39
2,3,3
13.523
9.7
6.6
5.8
Astrometry
29/20:15
2,3,2
13.837
9.2
7.4
6.6
Astrometry
29/21:51
1,2,2
13.693
8.6
7.0
6.4
WFPC2
29/23:34
2,3,3
13.477
9.9
6.8
6.0
WFPC2
30/01:11
2,3,3
13.477
8.9
6.8
6.0
WFPC2
30/02:46
2,3,3
13.477
7.2
6.4
5.8
Reacq
30/04:22
2,3,2
13.864
7.6
7.1
6.7
WFPC2
30/05:58
2,3,2
13.864
8.3
7.2
6.7
WFPC2
30/07:34
1,3,1
12.914
6.5
5.7
4.9
WFPC2
30/09:09
1,3,1
12.914
5.8
5.2
4.8
WFPC2
30/10:45
2,1,2
11.955
3.6
3.1
2.7
Mars
30/15:24
2,0,2
13.144
7.7
6.6
5.9
Ast/1FGS
30/16:54
2,0,2
13.144
5.7
5.3
5.0
Reacq/1FGS
31/02:38
2,3,3
13.970
7.7
7.0
6.5
Acq test
31/04:13
2,3,3
13.970
8.4
7.3
6.5
Acq test
31/05:49
2,3,3
13.970
7.5
7.1
6.6
Acq test
31:08:52
2,3,3
13.991
7.9
7.2
6.6
Astrometry
Note that the DVTHEP jitter during persistent disturbances from simulations is ~2-3 mas larger than science
7
instrument jitter for faint stars
TIPS
New Kalman Filter Sun-Point Safemode
• The Safe Mode Flow Down
Science Mode
Inertial Hold
Kalman
Filter
Sunpoint
Zero Gyro
Sunpoint
PSEA
Hardware
Sunpoint
8
Feb 21, 2008
TIPS
KFSP Performance
Feb 21, 2008
• Design Goals were for better performance than ZGSP
• KFSP performance met ALL expectations
– Entries into orbit day following captures during orbit night had
no discernable attitude errors
– Captures had minimal overshoots
– Slews to the sun-line appeared to be pure eigenvector maneuvers
– No noticeable rates about the sun-line after capture
• One of the major advantages of KFSP over ZGSP is that the
attitude is held even at night such that the aperture door is
not required to be closed
9
TIPS/JIM
February 21, 2008
Agenda:
INS Division News (Jerry Kriss)
An Unexpected Hysteresis Effect Seen in Hawaii-2RG Detectors (Jay
Anderson)
One-Gyro Science On-Orbit Test & Kalman Filter Sunpoint Safemode
Test (Merle Reinhart)
WFPC2 1-Gyro Test Results (Matt McMaster)
One-Gyro Operations FGS Observations (Ed Nelan)
Next TIPS/JIM: March 20, 2008
1
WFPC2 1-Gyro Test Results
Matt McMaster
Marco Sirianni
1
The Test
•
Program 11077 was initially designed for ACS/HRC using the TGM original
program test as a template.
•
11077 was converted to WFPC2/PC by Matt McMaster maintaining an
observational strategy very close to the original.
•
Attention was focused on the PC because the undersampling was less
severe than for the WFs WFPC2/PC 0.46 mas (ACS/HRC 0.26 mas)
•
The program consisted of multiple exposures of two rich star clusters: NGC
5904 and NGC 6341.
•
Two sets of observation were taken, one on Jan 29 in 2-gyro mode and the
other on Jan 31 in 1-gyro mode.
Target
RA (2000)
Dec (2000)
Guide Star
Brightness
Exptime
(Sec)
Number of
Images
NGC 5904
15 18 28.14
+02 07 9.80
V≈14
10,100,400
28
NGC 6341
17 17 7.05
+43 17 58.25
V≈13 and 14
10,100,400
140
2
The Analysis
• The software developed for the TGM test was modified to be
used with WFPC2 data.
• The FWHM of the PSF for stars with S/N > 10 was calculated
by fitting a gaussian profile to the stellar light profile
– Resulted in tens to hundreds of measurement per image
depending on exposure time and richness of the cluster
• All of the measurements in each image were averaged to
produce a mean PSF for the observation
2-Gyro
1-Gyro
3
Results
PSF FWHM distribution
(unit: PC pixel -all data included)
2- Gyro
Mean
Min
Max
: 1.67 pix ± 0.16
: 1.13
: 1.99
Mean
Min
Max
: 1.65 pix ± 0.14
: 1.09
: 1.89
1- Gyro
The average PSF FWHM is remarkably similar indicating no obvious
degradation in performance in 1-Gyro mode
4
Results – (cont.)
As done for the TGM test, the dependence of the FWHM
on exposure time, guide star brightness, and position on
the sky was analyzed:
Guide Star Brightness (Mag)
V=12.91
V=13.86
There is no difference
between images taken
with a V=13 and V=14
guide star
There are small
differences in the PSF
width due to the
exposure time duration.
10 sec
1 - gyro
2 - gyro
FWHM
1.63
1.65
σ
100 sec
1 - gyro
2 - gyro
FWHM
1.71
1.70
σ
400 sec
1 - gyro
2 - gyro
FWHM
1.82
1.85
σ
Average
1 - gyro
2 - gyro
FWHM
1.68
1.70
σ
5
0.01
0.01
σ
FWHM
1.62 0.01
1.67 0.01
0.01
0.01
σ
FWHM
1.69 0.01
1.70 0.01
0.02
0.04
σ
FWHM
1.82 0.03
1.86 0.03
0.01
0.02
σ
FWHM
1.68 0.02
1.72 0.02
Data from NGC 6341 only
Results - (cont.)
2 – GYRO
Exptime
FWHM
10 sec
100 sec
400 sec
1.66 ± 0.03
1.70 ± 0.03
1.85 ± 0.04
1 – GYRO
Exptime
FWHM
10 sec
100 sec
400 sec
1.63 ± 0.02
1.70 ± 0.04
1.82 ± 0.05
Such differences were also noted during the original 2-Gyro on orbit
verification test with the ACS/HRC.
6
Results – (Cont.)
The average PSF width in NGC 5904 data is systematically
smaller than in NGC 6341, but there is no dependency on the
gyro guiding configuration.
Target
1 Gyro
2 Gyro
NGC 5904
1.41 ±0.04
1.46 ±0.07
NGC 6341
1.68 ±0.01
1.71 ±0.01
A similar result was found for the clusters observed in the
original 2-gyro on-orbit test with HRC
7
Conclusions
There is no evidence that
the quality of the science
data obtained in 1-gyro
mode is any worse than
in 2-gyro mode.
NGC 6341 /PC
1-Gyro mode
F555W -100 sec
8
TIPS/JIM
February 21, 2008
Agenda:
INS Division News (Jerry Kriss)
An Unexpected Hysteresis Effect Seen in Hawaii-2RG Detectors (Jay
Anderson)
One-Gyro Science On-Orbit Test & Kalman Filter Sunpoint Safemode
Test (Merle Reinhart)
WFPC2 1-Gyro Test Results (Matt McMaster)
One-Gyro Operations FGS Observations (Ed Nelan)
Next TIPS/JIM: March 20, 2008
1
One-Gyro Operations
FGS Observations
Tips
Feb 21, 2008
Ed Nelan
One Gyro Science - FGS
• One-Gyro test included 5 orbits of FGS “astrometry”
• FGS2r & FGS3 guided
• FGS1r observed a bright star in POS mode for the
duration of the orbit.
– provides an independent check of PCS performance.
• One of the orbits used FGS2r in “single guide star”
mode (no roll star).
– This orbit used two targets in FGS1r to detect roll
changes.
• Merle Reinhart scripted the phase2 proposal (11078).
One Gyro Science - FGS:
guide stars
visit
Dom GS
mag
Sub GS
mag
01
NABC000295F3
13.0 NABC000109F2
02
NABC000350F3
13.7 NABC000137F2 14.19
03
NABC000112F2
14.0 NABC000350F3
13.7
04
NABC000146F2
13.3
none
-----
06
NABC000038F3
14.2
N7IF000091F2
12.9
13.9
Visit 01
V=13.9
V=13.0
Upgren69
V=9.6
Visit 02
V=14.2
Upgren69
V=9.6
V=13.7
Visit 03
V=14.0
Upgren69
V=9.6
V=13.7
Visit 04
star1
V=9.6
Star2
V=13.1
guide star
V=13.3
Visit 6
V=14.2
star1
V=9.6
V=12.9
One Gyro Science:
observed jitter in FGS1r
visit
01
Dom
GS
F3
02
mag
mag
13.0
Sub
GS
F2
F3
13.7
F2
14.2
3.2
3.9
03
F2
14.0
F3
13.7
2.8
4.2
04
F2
13.3
none
-----
2.3
3.3
06
F3
14.2
F2
12.9
3.1
3.4
13.9
X*
Y*
(mas) (mas)
2.6
4.7
* This is the standard deviation of the FGS1r centroids
One Gyro Mode:
astrometry summary
• FGS1r observations under 1-gyro mode suggests that PCS
performance is not degraded relative to 2-gyro (or 3-gyro)
operations.
• Visit 04 (single guider) did not exhibit any roll changes greater
than what is observed under single guider in 2-gyro & 3-gyro
operations.
– Single FGS guiding appears to be “fine” in 1-gyro operations.
• There appears to be no reason to avoid using faint guide stars
(V~14) in 1-gyro operations.