NICMOS SMOV Update
October 07 2009
Agenda
1. Recent & Upcoming Activities
2. NICMOS SMOV Program Status
3. Recent Results and Analysis
- Dark Monitoring
- Focus Measurement
1
Recent Activity:
• 275:16:34 NCS Set-Point changed from 77K to 76K (Fri Oct 2)
• Daily dark monitoring (prog 11947)
• 11408:1 278:10:51 Focus measurements NIC1/NIC2/NIC3 (Mon Oct 5)
Planned activities:
— 11408:2 281:09:33 Update of nominal PAM settings visit 4 (Thu Oct 8)
— 11408:3 281:11:17 PAM Tilt Observation visit 5, 6, 7 (Thu Oct 8)
— 11408:4 285:14:42 Update of nominal PAM Tilt visit 8 (Mon Oct 12) if needed
— 11947 Dark Monitoring continue with daily darks
2
NICMOS SMOV Status
Activity
Prop ID
Title
PI
Visits
Done
Total Visits
Status
NIC03
11406
DC Transfer Test
Schneider
2
2
Completed
NIC04
11407
Filter Wheel Test
Wheeler
4
4
Completed
NIC05
11408
Focus/Tilt Test
Wiklind
3
8
In progress
NIC06
11409
FOM Functional
Dahlen
0
(1)
waiting
NIC07
11410
Aperture Location
Koekemoer
0
3
waiting
NIC08
11411
Optical Plate Scale
Wiklind
0
(3)
waiting
NIC09
11412
Geometric Stability
Wiklind
0
(2)
waiting
NIC10
11413
Mode-2 Coronagr. Target Acquisition
Schneider
0
(5)**
waiting
NIC11
11414
Optimum Coronagraphic Focus
Schneider
0
(2)
waiting
NIC12
11415
Coronagr. Performance Assessment
Schneider
0
(5)**
waiting
NIC13
11416
Thermal Characterization*
Barker
0
(100)
waiting
NIC14
11417
Detector Read Noise and Dark Current*
Dahlen
0
86
waiting
New
11947
Dark Monitoring (C17 Cal Program)
Dahlen
35
(59)
In progress
*) Will start after NIC06 (FOM Functional)
**) Number of orbits changed
Visits in parenthesis are under review for change or removal
3
Recent Results
• Dark Monitoring
— Darks have been obtained at three different NCS set-points: 75, 77 and 76K
— The NCS set-point was decreased to 76K on Fri Oct 2
— The increase in linear dark current compared to 72.4K is ~?% for NIC1 and
NIC2 and ~?% for NIC3
— All three cameras show an increase in the number of hot/warm pixels as well
as changes in the structure of the dark current variation
– Increased dark current levels increase the noise contribution for deep
observations in narrow band filters but have a marginal impact on short exposures
(read-noise limited) and broad band filters where the DQE gain offsets the increase
in dark current
– The main reason for lowering the set-point to 76K is a concern about the stability
of the NIC3 dark current structure
4
Recent Results
5
Recent Results
Distribution of dark current (total) for the
difference image (75 – 72.4, 76 – 72.4 &
75 – 72.4).
NIC1 and NIC2 shows mainly a shift to
higher e-/s, with a slight increase in the
high current tail.
NIC3 shows a marked increase in the
high current tail, indicating an increase in
the low S/N structure
6
Recent Results
NIC1
NIC2
NIC3
75K
15.8%
76K
24.2%
77K
29.4%
75K
15.8%
76K
25.6%
77K
31.2%
75K
15.8%
76K
36.7%
77K
45.8%
Quantifying the warm dark current tail:
Fraction of pixels above a dark current
level (total) corresponding to a distance
from the peak that is 1σ of the average
72.4K (pre-SM4) peak.
7
Recent Results
Linear Dark Current [e-/s]
NCS Set Point
Camera
72.5
Ratio
75K
Ratio
76K
Ratio
77K
Ratio
NIC1
0.09 ± 0.02
1.0
0.14 ± 0.02
1.6 ± 0.4
0.15 ± 0.02
1.7 ± 0.4
0.18 ± 0.02
2.0 ± 0.5
NIC2
0.08 ± 0.02
1.0
0.12 ± 0.02
1.6 ± 0.5
0.13 ± 0.01
1.8 ± 0.5
0.16 ± 0.02
2.1 ± 0.6
NIC3
0.13 ± 0.03
1.0
0.35 ± 0.03
2.7 ± 0.7
0.53 ± 0.03
4.1 ± 1.0
0.67 ± 0.03
5.2 ± 1.3
8
Recent Results
Focus
9
Recent Results
Focus
7 stars
19 stars
Correcting for Focus Field Variations
No breathing correction
10
Recent Results
Three different focus determinations:
GS
DT
TW
No FFV
#stars
No FFV
FFV corrections
#stars
NIC1
+2.52 ± 0.11
3
+2.40 ± 0.04
+2.43 ± 0.11
7
NIC2
+0.91 ± 0.28
4
+0.46 ± 0.04
+0.77 ± 0.10
19
NIC3
Out of focus
3
Out of focus
Out of focus
?
Pre-SM4 best focus positions:
Adopted best focus positions:
NIC1:
NIC2:
NIC3:
NIC1:
NIC2:
NIC3:
+1.9 mm
+0.2 mm
–9.5 mm
• SM move July 20 2009 of +2.97 microns
• Corresponds to +0.4mm in PAM space
• Focus shift consistent with SM move plus a
small change from pre-SM4
+2.4 ± 0.11 mm
+0.8 ± 0.11 mm
–9.5 mm
• The nominal PAM positions for NIC1 and
NIC2 will be updated to:
 NIC1: +2.3 mm
 NIC2: +0.7 mm
 NIC3: no change
 NIC1-2: +1.7 mm (from +1.2mm)
11
Recent Results
12
Recent Results
Glenn Schneider
13