TIPS-JIM Meeting
19 February 2004, 10am, Auditorium
1.
A Simulation-Based Correction for
STIS CTI
Paul Bristow, ECF
2.
New Challenges to Scheduling JWST
Peter Stockman
3.
JWST Science Working Group Activities
Massimo Stiavelli
4.
Cycle 13 Proposal Statistics
Brett Blacker
Next TIPS Meeting will be held on 18 March 2004.
www.stecf.org/poa
The CE-STIS CTI Preprocessor- BETA
Paul Bristow TIPS Feb’04
The STIS Calibration
Enhancement Project
According to an ESA/NASA MoU
A comprehensive empirical calibration pipeline
already exists for STIS. We aim to improve
those components which benefit from physically
motivated corrections.
Current work includes:
Wavelength
Calibration
Calibration lamp line list - new lab measurements at NIST
Optical Model
Optimal
Spectral Extraction
Detector Model
Pre-processor: Overview
Readout model:
Concept
Implementation
Validation
Pre-processor script
Handling
reference files
BETA version ready for testing
In
order to progress beyond BETA, needs criticism
Readout model: Motivation
A physical solution, CTI effects understood in
terms of the CCD operation and environment
A correction that applies to the entire 2D array:
Equally
valid for imaging and spectroscopy
Also applicable to extended objects
Portable to other space based detectors
(WFPC2, ACS, WFC3?, Kepler instruments etc.)
Extendable to model further aspects of CCD
readout
Readout Model: Concept
Forward Simulation:
Start
with
2D Charge distribution on chip
Distribution of bulk traps
Shift
the charge under each electrode as during
readout
Calculate capture and emission of charge in each
shift
Take into Account:
Status
of bulk traps
Dark current
Trap capture and emission timescales
Chip clocking frequency, architecture, gain etc.
Currently only deals with parallel CTI
Correction:
Raw
data
=
>> SIMULATION
Simulation
output
=
-
Raw
data
Difference
image
Raw
data
Difference
image
Corrected
image
Further iterations (usually not necessary):
Corrected
image
>> SIMULATION
Readout direction
Cleaning CTE Trails
Raw Data
Quantitative Validation
Matches photometric and spectroscopic empirical
corrections (Goudfrooij & Kimble 2002, Bohlin & Goudfrooij 2003)
well with physically realistic parameters
Charge restored reliably to central isophotes of point
sources => whole image array is corrected reliably.
2 CE-STIS ISRs describing these results
Many parameters still not well confined - there is a lot of
parameter space to search!
Still some outstanding issues regarding the more
precise chip details.
The CTI Pre-Processor Pipeline
Originally developed to automate testing and
comparison to empirical models
Automated application of CTI correction,
CALSTIS pipeline and evaluation of corrected
data
Designed so that the CTI correction is a stand
alone processing step executed before CALSTIS
and completely independent of CALSTIS
CALSTIS is run as for normal raw dataset
CTI Pre-processor Tasks:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Extracts relevant header details
Corrects dark and bias reference files
Updates dark and bias file keywords in header
Prepares raw data for readout simulation
Simulation goes forward (adds CTI effects)
Simulates read out of all sub-exposures in raw data
Compares output to input, difference subtracted directly from raw
science extension [1,4,7…]
Runs CALSTIS on corrected raw and original raw data
Automatically extracts sources/spectra from CTI corrected and
uncorrected calibrated data
Uses empirical corrections as a comparison for extracted
sources/spectra.
Darks also require CTI
correction
Readout simulation
reproduces some of the
signature which is present in
the standard bias files =>
bias files must be updated
The pre-processor:
obtains required reference files
corrects them
updates the raw header
New ISR discussing this
Dark reference image before
and after CTI correction
Readout direction
Dark and Bias Reference Files
Dark and Bias Reference Files
Modify dark
Modify bias
Correct CTI and calibrate
Calibrated
Data
Readout direction
Calibrated
Data
Readout direction
Summary
Modeling concept works
Pipeline implementation developed as preprocessor to CALSTIS
Available
for testing internally (ST-ECF/STScI)
Still very much under development
Potential to be exported to WFPC2, ACS
ISRs available from:
www.stecf.org/poa
Software directly from me:
bristowp@eso.org
Criticism very welcome, without it this won’t get
beyond BETA!
Scheduling Challenges for JWST
JIM Feb. 19, 2004
Peter Stockman
Major planning constraints
Sun avoidance: well known Field of Regard
2. Earth-Moon scattered light: Will constrain some
orientations (still not completely understood)
3. Orbit maintenance (11 days between angular momentum
dumps for FDF): would constrain roll choice/orientation
for long observations
4. Fuel conservation (22 days between angular momentum
dumps): would constrain the roll constraints of all
observations and potentially the mix of observations in a
22 day period.
Red = New and Exciting
1.
2/19/04
JIM
Simple model based upon 2001 TRW
sunshield design by Dennis Skelton
1.) Sun Avoidance
•
The sunshade
provides:
•
•
-5° to 45° pitch from
the ecliptic poles
~± 5° of operational
roll
•
•
2/19/04
Sunshield shadows
Primary & Secondary
Mirrors
Required for 10 day
fixed-roll NIRSpec
observations.
Primary shadows
Secondary Mirror
Stayout Zone
5° safety band in both
pitch and roll
JIM
56°
2.) Simple L2, Earth, Moon Geometry
in X-Y plane shows how Earth and Moon
light can strike OTE
Sun
projection
±10° roll shadow band, ±5°in MRD
•
Earth
Moon
37°
27°
•
L2
JWST
2/19/04
JIM
The Earth and/or
Moon can illuminate
the optical surfaces,
particularly at L2
orbit (Y and Z)
extremes
Could be improved by
tighter L2 orbit or
larger sunshade.
Earthshine typical example
OTE components
overhanging
sunshield coverage
will be illuminated by
Earth crescent
•Northern hemisphere
•Pitch = 0
•Sunshield Roll = 0
•Yaw = 45
2/19/04
JIM
Scattered Earthshine can exceed the
zodiacal background at λ> 3 µm.
Earthshine NGST OTA Heated by Sunshield
Sunshield T=90K, ε=0.05; 20% Bandpass
Zodi
Worst case
assumes:
• 100% of 1 mirror
(SM or PM)
• 1% dust
• Nominal BRDF
1.E+05
1.E+04
1.E+03
Earthshine
Zodiacal
Light
1.E+02
1.E+01
Detector
1.E+00
1.E-01
Dust Scattered
Sunshield Thermal
1.E-02
Mirror
Thermal
Moonlight is less
important (1-3%
Zodi)
1.E-03
Moonlight
1.E-04
1.E-05
0
5
10
15
20
25
30
Wavelength [ µm]
From Larry Petro
2/19/04
JIM
Beckman analyzed one DRM for
Earth/Moon Impacts
•
For analysis, he used:
•
•
•
Skelton’s stay out zones from 2001 TRW Phase 1 design
15 yr ephemeris and DRM v3.6b
Periods exist when either the Earthlight or
Moonlight would strike the primary or secondary
mirror
15 yr JWST orbit
seen from the Sun
2/19/04
JIM
Results
•
•
70% of observations were “dark”
Earth and Moon each affected 25% of observations:
•
•
•
2/19/04
Earth intruded as much as 22° into keep-out zone
Moon intruded as much as 30° into keep-out zone
Very little correlation
with time, but both Moon
and Earth most easily
seen at X-Y-Z extremes
of the orbit.
JIM
Earth seen in L2 XY plane
Earth
1.5Mkm
The new sunshield (June 2003) is 43%
smaller than previous design to reduce
angular momentum buildup and mass
Design in proposal
New design
•67% area (based on inner layer)
•57% area (based on outer layer)
The smaller sunshade will increase the impact of
scattered light from the Earth and Moon.
2/19/04
JIM
A rough idea of the constraint
and how it changes per year
Pattern repeats
• 90 L2/2
•180 L2
Increased
scattered
light
regions
NEP FOR in JWST frame
NEP
•~1 year
Can create
shorter
observing
seasons and
impact 180 day
repeats
2/19/04
Z
JWST
L2
JIM
JWST
3 weeks
Y
Later
L2
3.& 4.) Angular Momentum and
Orbit Maintenance:
•
•
•
To determine orbit, FDF is allowing at most 2
momentum dumps per 22 day period (e-folding
time for orbit errors).
Limited propellant mass for orbit maintenance and
momentum dumps has led to concept of 1
dump/22 days (24 hrs before orbit burn)
Flexibility for scheduling depends on wheel
momentum storage capability
•
•
2/19/04
6 wheels = 40 n-m-s
4 wheels = 22 n-m-s
JIM
Schematic Maneuver Sequence
Possible
Additional
Momentum
Unload
21-day
Tracking
Arc
Momentum
Unloads
(~ 1 day prior
to SK maneuver)
2/19/04
JIM
Station-Keeping
Maneuvers
(8 per rev,
~ 22 days apart)
Momentum accumulation is dominated
by roll offsets in current design
1/5th of 22 day
total accumulated
in one day!
dJ/dt
Pitch
2/19/04
Roll
JIM
Comparison of momentum accumulation for
both new sunshields designs
Current design
(negative dihedral)
Positive dihedral
alternative
2/19/04
JIM
Note
significant
angular
momentum
due to pitch
alone
Possible ways to manage angular
momentum in the scheduling system
•
•
Baseline today: Monitor: Check long range plan to see if
there is a potential for exceeding the momentum between
22 day dumps. Feasible if problems are rare
Restrict average momentum buildup per observation to less
than 2 n-m-s average during development of LRP.
•
•
•
•
Actively Manage momentum by balancing angular
momentum build-up over each 22 day period (and
potentially beyond) in the LRP.
•
2/19/04
Constrain roll orientation and start-dates
Significantly decreases scheduling flexibility.
Failed observations will necessitate replan since all observations
would be shifted
Increases science return, but may create a a very brittle schedule.
JIM
Monitor Study:
DRM shows 30-40% of dump intervals less
than 22 days
Cumulative Distribution of Dump Intervals
40 Nms Limit, JMS v1.0_wmk135
100%
of Dump Intervals
Cumulative Fraction
.
.
90%
80%
70%
60%
50%
10 Day Visit Limit
40%
1 Day Visit Limit
30%
20%
10%
0%
0
20
40
60
80
100
120
140
Time Since Previous Dump [Days]
Monitor method will not work. Fails in 30-40% of
cases even with all reaction wheels working.
2/19/04
JIM
160
Restricting to an average momentum :
10 day observations need special planning to
avoid excessive momentum build-up
Available Start Time per Year with Early Visit Start for 10 Day Visit and
Mean Momentum Limit of 40 Nms / 22 day
0°
Ecliptic Latitude
30°
15°
45°
60°
75° 90°
360
0.0 Day
Availability per Year [Days]
At high ecliptic latitudes, the
visits must be centered within
one day: either fixed start times
or intervention needed if
started early by failure of
previous observation
0.5 Day
300
1.0 Day
1.5 Day
240
2.0 Day
180
120
60
0
0%
10%
20%
30%
40%
50%
60%
Cumulative Fractional Sky Area
2/19/04
JIM
70%
80%
90%
100%
Restricting to an average momentum :
One day visits are also constrained
Available Start Time per Year with Early Visit Start for 1 Day Visit and
Mean Momentum Limit of 40 Nms / 22 day
0°
Ecliptic Latitude
30°
15°
45°
60°
75° 90°
360
0.0 Day
0.5 Day
Availability per Year [Days]
300
Note drop in available
Start-time at high
ecliptic latitudes even
for a 1-day early visit
1.0 Day
1.5 Day
2.0 Day
240
180
120
60
0
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Cumulative Fractional Sky Area
2/19/04
Restricting average momentum method will be very
constraining…worth going to total momentum
JIM
management
Restricting average momentum : Loss of
reaction wheel leads to drastic constraints
Available Start Time per Year with Early Visit Start for 1 Day Visit and
Mean Momentum Limit of 24 Nms / 22 day
0°
Ecliptic Latitude
30°
15°
45°
60°
75° 90°
360
0.0 Day
0.5 Day
Availability per Year [Days]
300
1.0 Day
1.5 Day
2.0 Day
240
Note loss of all flexibility
above 45° even for 1 day
observations.
180
120
60
0
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Cumulative Fractional Sky Area
Restricting average momentum method is not viable.
Must go to total momentum
management or change
2/19/04
JIM
vehicle
A typical 22 day managed schedule
Possible 22 day rules
• Only one 8-10 day obs
• Only one 4-7 day obs
• Fill in with 1 day obs
2/19/04
JIM
Summary
•
Overall scheduling of JWST has become more complicated
and may significantly impact JWST science:
•
•
•
•
•
•
2/19/04
Long observations are almost time critical
Full roll (± 5°) is not routinely available
Even observations with varying roll but in the same part of the sky
will be limited to ≤ 10 day stretches.
Thermal radiation from the Earth can produce significant scattered
light and preferred observing seasons (potentially impacting NGP
& SGP depending on launch date)
Angular momentum issue could be mitigated with positive
dihedral design, increased momentum wheel capability or
added fuel (~ 70 kg).
Scattered light issue needs to be confirmed by Ball, STScI,
and GSFC (Beckman/Skelton). Larger sunshield makes
angular momentum problem worse.
JIM
Report on JWST Science Working Group
Tucson, 10-11 Feb 2004
1
Major news
No intention of accelerating the schedule. A list of items
suitable for risk reduction is being prepared by the JWST
project and were briefly discussed by the SWG.
Instruments ok.
2
JWST Field of View Layout
3
Major news
No intention of accelerating the schedule. A list of items
suitable for risk reduction is being prepared by the JWST
project.
Instruments ok.
4
Major news
No intention of accelerating the schedule. A list of items
suitable for risk reduction is being prepared by the JWST
project.
Instruments ok.
NIRCam : PIL is #1 risk reduction item. Tip-tilt focus mechanism.
5
NIRCam
OTE
Pupil
Imaging
Lens would
go here.
Pick-off mirror and
Tip-tilt-focus mech.
One half of NIRCam
6
Major news
No intention of accelerating the schedule. A list of items
suitable for risk reduction is being prepared by the JWST
project.
Instruments ok.
NIRCam : PIL is #1 risk reduction item. Tip-tilt focus mechanism.
NIRSpec: issue of pupil shear, potential loss of sensitivity in
NIRSpec 14-15% for 5% shear. Swiss company has produced
cryogenic mechanical slit selector (backup to MEMS)
SWG will carry out trade study for 1/10/100 slits by June 04
MIRI: shear also an issue for coronagraph. Extra background at
>20µm.
FGS-TF: the SWG voted for uninterrupted wavelength coverage
up to 5 µm.
Survey Fields
7
Backgrounds – South galactic cap
Red = galactic dust, green
= ecliptic declination, blue
= selected fields (low dust,
no bright stars, galaxies,
radiosources)
8
Backgrounds – South galactic cap
Red = galactic dust, green
= ecliptic declination, blue
= existing fields (symbol
size proportional to quality)
9
Major news – cont’d
Discussion on need for some form of science parallels
Long discussion about HST-JWST Legacy
JWST science may require visible imaging data
How do we make sure those data are there when
needed?
Full range of opinions (from do nothing to ask for a
fraction of HST time to be set aside).
Too early for promising a JWST Quick look survey
Agreement on doing nothing but informing the user
community about what JWST can and cannot do and
where in the sky
Write a JWST Mini-handbook (?)
10
TIPS
Cycle 13 Phase I Status
Brett Blacker
Science Policies Division
February 19, 2004
Phase I Schedule for Cycle 13
•
•
•
•
•
•
•
•
•
•
•
Oct 7
Dec 3
Jan 23
Feb 9
Mar 16/17
Mar 22-24
Mar 25-27
Apr 1
Apr 2
Apr 13
Apr 30
Thursday, February 19, 2004
CP Release
APT Release
Phase I Deadline
Ship CDs to Panelists
Prelim grades and comments
Panels meet
TAC meets
Director’s Review
Notifications
Send Approved Comments
Send Rejected Comments
Brett S. Blacker: TIPS
2
Help Desk Calls
• APT Platform
– 21 Submission questions (34 last year)
– 8 Installation questions (30 last year)
– 63 Writing Proposal (110 last year)
• 4 PDF Conversion Problems (32 last year)
• SPD Platform (about the same as last year)
–
–
–
–
6 Documentation
17 Policies
10 Templates
12 Scheduling/OSF Format
Thursday, February 19, 2004
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Cycle 13 User Submissions
System
Linux
42
Change from
Cycle 12
+ 2.1%
SunOS
27
- 6.8%
Windows
15
+ 1.2%
Mac OS X
13
+ 5.6%
Thursday, February 19, 2004
% Received
Brett S. Blacker: TIPS
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APT Phase I Feedback
•
Have received unsolicited Positive feedback on APT Phase 1 tool
–
–
–
–
–
–
•
I just sent off my complete proposal draft to my CoIs. This was my first exposure to this system, and I had
no personal instruction in its use. I found it clear, effective, and convenient to use, and I experienced zero
problems at any stage. My compliments!
My personnel experiences with APT were also all positive and I received the automated and your email
confirmations in a timely fashion for all of the proposals I was involved in. Seemed smooth as silk this
year, from my end!
Please find hereafter my first proposal. Thanks for simplifying our life with this electronic submission
system. I really appreciate to prepare this proposal through this system.
That's it, except my compliments to the APT design and development team. Proposal submission has
sure come a long way since Cycle Zero!
I just submitted a SIRTF (aka SST) proposal using their SPOT software, the counter-part to APT. I thought
you would be interested to know that SPOT is very user-unfriendly and un-intuitive, much much more
than APT ever was. For example, I couldn't figure out a way to look at the proposal as a whole to see if it
was picking up the right pieces. Anyway, I also just finished using APT to submit several HST proposals,
and it really is very nice.
Last year you were the recipient of a long complaining email bemoaning the whole APT/proposalsubmittal process. In fairness, and out of a desire to present a balanced view, I would like to report that
everything went very well atmy end this year. It was like night and day. No problems at all. Last year the
APT windows did not open properly on my machine, but this year it was fine.I want to thank our local
staff, who solved the PDF-not-printing-properly problem by installing the latest version of Acroread.
However, I would infer that you must have made some changes at your end, too.
Email survey to all PIs and CoIs also went out
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Submission Statistics
• 949 Proposals Received in Cycle 13 (1046 in
Cycle 12)
– 739 (819) GO for 17,257 (19,674) orbits
• 11 (10) Treasury for 1415 (2202) orbits
• 30 (31) Large for 4292 (3672) orbits
• Future Cycle orbits requested
– 1714 (1860) for Cycle 14
– 212 for (855) Cycle 15
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Stats continued
• 82 Snapshot props for 5364 targets
• 128 Archival Research proposals
– 89 Regular
– 33 Theory
– 6 AR Legacy
• 2 Calibration Outsourcing Props for 2 prime
and 20 Pure parallel orbits
Thursday, February 19, 2004
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ESA/STScI Stats
• 170 Proposals submitted from ESA PIs
– 155 GO for 2895 orbits
– 12 Snaps for 989 orbits
– 2 ARs
• 89 Proposal submitted from STScI PIs
– 63 GO for 1904 orbits
– 11 Snaps for 686 targets
– 15 Ars (4 Theory & 9 Regular)
Thursday, February 19, 2004
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Joint Coordination Proposals
• Chandra Submissions
– We can allocate 400 ksecs of which only 80 ksecs
can be time-constrained
– 20 proposals requesting 377 HST orbits and 1181
ksecs
• NOAO Submissions
– We can allocate 15-20 nights on most telescopes
– 15 props requesting 485 HST orbits and 54 NOAO
nights
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Science Category Breakdown
Category
# Submitted
% Submitted (Cy12, 11)
AGN/Quasars
113
11.9 (13.3, 11.8)
Cool Stars
70
7.4 (11, 9.2)
Cosmology
80
8.5 (6.9, 8.6)
Galaxies
187
19.7 (18.1, 18.6)
Hot Stars
127
13.4 (12, 12.3)
ISM
114
12.0 (13, 11.8)
Quasar Absorption Lines
46
4.8
Solar System
58
6.1 (5.4, 5.6)
Star Formation
44
4.6 (6.1, 6.9)
Stellar Populations
110
11.6 (10.2, 11.2)
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(4, 3.9)
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Science Category Breakdown
Category
Orbits
% Submitted (Cy12, 11)
AGN/Quasars
1686
9.8 (10.9, 10.8)
Cool Stars
850
4.9 (6.7, 6.8)
Cosmology
2914
16.9 (22, 19.7)
Galaxies
3879
22.5 (16.4, 24)
Hot Stars
1575
9.1 (7.9, 6.9)
ISM
1437
8.3 (8.7, 7)
Quasar Absorption Lines
1145
6.6 (3.7, 3.6)
Solar System
416
2.4 (3.1, 2.5)
Star Formation
761
4.4 (6.5, 6.1)
Stellar Populations
2579
15 (14.2, 12.5)
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