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
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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.
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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!
An Unexpected Hysteresis Effect
Seen in Hawaii-2RG Detectors
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Background
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Distortion calibration important for JWST
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Coronagraphy, MSA, slits
Self-calibration will be difficult
ACS field observed in 2006
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In LMC, in JWST’s CVZ
5′×5′: big enough for all detectors
Good density of stars
Many well-measured stars
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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
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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