Äîêóìåíò âçÿò èç êýøà ïîèñêîâîé ìàøèíû. Àäðåñ îðèãèíàëüíîãî äîêóìåíòà : http://www.stsci.edu/hst/wfpc2/documents/preshipoptic.pdf
Äàòà èçìåíåíèÿ: Thu Jun 17 17:48:03 2010
Äàòà èíäåêñèðîâàíèÿ: Fri Jun 25 22:31:09 2010
Êîäèðîâêà:

Ïîèñêîâûå ñëîâà: coma
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WFPC2 Optical Test Results

User's Committee Chris Burrows 28-May-1993 1

Pickoff Mirror works

W2
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Phase Retrieval Commanded Positions

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WFPC2 Optical Test Results

User's Committee Chris Burrows 28-May-1993 2

AF Ms Work

W4
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Phase Retrieval Commanded Positions

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WFPC2 Optical Test Results

User's Committee Chris Burrows 28-May-1993 3

Phase Retrieval Commanded Positions

Coma is Correctable
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WFPC2 Optical Test Results
PC1

User's Committee Chris Burrows 28-May-1993 4

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Phase Retrieval Commanded
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Nominal and Cold orbit data overplotted Each tickmark is 0.01 microns rms Zero volts is at center of hexagon formed by 44 V settings on single actuators and pairs "Flight" setting is near origin - zero coma

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WFPC2 Optical Test Results
Comparison of raytrace, Actuate program, and best fit gain factors.
Ray POMM % shearlstep POMM pixels/F/step POMM pixels/% AFM % shear/arcsec AFM pixels/F/arcsec AFM Pixels/%/F
0.269 0.216 0.802 0.022 0.0037 0.168

User's Committee Chris Burrows 28-May-1 993 5

Actuate Fit
0.279 0.200 0.717 0.023 0.0047 0.203 0.232 0.213 0.918 0.018 0.0037 0.207

Image motion follows the prediction closely. Phase retrieved coma has a gain factor about 20% less than expected.
This may be because of pupil function changes in the misaligned camera.


(Q) 1l'Sl1TUTE

WFPC2 Optical Test Results

User's Committee Chris Burrows 28-May-1993 6

Aberrations are small
WF2
X-Coma standard deviation V-Coma standard deviation Astigmatism 45 degree astigmatism Spherical aberration 5th order spherical Focus from 1260 from sharpness Overall wavefront error microns rms 0.003 0.007 -0.011 -0.016 -0.003 0.002
0.003

WF3
0.005 0.004 0.008 0.022 -0.008 0.001
-0.03

WF4
0.004 0.004 0.009 -0.008 -0.008 -0.001
-0.01

PC1
0.005 0.003 0.008 0.010 0.001 0.001
0.026

0.022 29.26

0.037 16.92

0.017 37.28

0.03 21.42

1/waves at 6328

Results do not include subtraction of Stimulus aberrations, and addition of OTA aberrations (breathing, collimation, mid frequency errors, trefoil) Wavefront error is dominated by focus offsets between cameras.


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WFPC2 Optical Test Results

User's Committee Chris Burrows 28-May-1993 7

Phase retrieval is consis tent
Orbit AlignLamp FocusAstig(mm) 45 Deg. matism Astig. 3rd Ord. 5th Order ment Spher. Spherical

Flight Nominal Flight Nominal Flight Nominal Cold -10,-10 L7 Cold -10,+10L7 Cold Flight L7 Cold +10,-10L7 Cold +10,+10
Mean

L7 L8 L9 -0.12 0.02 0.01 -0.15 L7

0.02 0.03 -0.01 -0.0179 -0.0288 -0.0098 -0.0011 0.01
-0.011

-0.0083 -0.0152 -0.0137 -0.0312 -0.0182 -0.0147 -0.0190 0.0101
-0.016

-0.0175 -0.0156 -0.0175 0.0006 -0.0025 -0.0051 -0.0013 0.0024
-0.003

-0.0055 -0.0060 -0.0047 0.0023 0.0025 0.0023 -0.0021 -0.0028
0.002

0.0020 0.0026 0.0028

-0.0001

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Very different (50%) illumination patterns solved for Focus may be most affected by illumination uncertainties

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WFPC2 Optical Test Results
Sharpness is unexpectedly low
Focus Camera Median 0.0537 1324 PC WF2 0.0599 1286 0.1115 1286 WF3 0.1005 WF4 1286 WF2 Simulations: Measured aberrations 0.1844 +Pinhole size = 10 microns 0.2601 +Pinhole size = 20 microns 0.2305 +Pinhole size =30 microns 0.2007 +40 mas rms jitter 0.1567 0.1688 +PSF at pixel (0,0) Min Max Mean

User's Committee Chris Burrows 28-May-1 993 8

0.0802 0.2086 0.1946 0.1872

0.0666 0.0666 0.1460 0.1458 0.1494 0.1478 0.1420 0.1415

0.3314 0.2729 0.2751 0.1829 0.3167 0.2618 0.1765 0.3043 0.2353 0.1656 0.2516 0.2023 0.1434 0.1711 0.1563 0.3447 0.2634 0.2622


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WFPC2 Optical Test Results

User's Committee Chris Burrows 28-May-1993 9

PO MM was stable throughout TV
xpom
Pre-Environmental test 10 10 11 11 10 10 10

ypom
30 30 26 2 2' 28 28

pomx
-0.02 -6.65 -1.11 -0.92

pomy
-0.04 -9.35 3.24 3.25 1.91 1.84 1.96

Post-Env before rezero Post-Env test V @14 before adiust V @14 after adjust Thermal vac hot orbit Thermal Vac Cold orbit

-0.21
-0.43 -0.62

Note commanded steps do not exactly cancel coma changes. For example xpom+pomx should be constant. Post Env before rezero is POMM motion during shake, and before reestablishing zero position. Other motions are along V2 direction

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WFPC2 Optical Test Results

User's Committee Chris Burrows 28-May-1 993 10

Global Image motion
Proba bly caused by stimulus instabilities (M4) All motions excect cost enviroqmental along V2
--mgx
0.13 3.92 1.25 -7.78 -1.45 1.13 -1.59

targy
-0.05 -1.60 -1.04 1.30 0.57 -1.75 4.08

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Pre-Environmental test

Post-Env before rezero Post-Env test TV @14 before adjust TV @14 after adjust Thermal vac hot orbit Thermal Vac Cold orbit
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(QJ M,i'SITIUfE

WFPC2 Optical Test Results
Camera to camera shifts in WF pixels between tests.
xpre xpost xtv xtvc ypre ypost ytv

User's Committee Chris Burrows 28-May-1993 11

ytvc

WF2 WF3 WF4

PCl

0.000 0.295 0.662 -0.799

0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.073 -0.092 -0.495 -0.219 -0.173 -0.371 0.722 0.525 0.300 -0.143 -0.374 -0.179 0.065 -0.486 -0.630 -0.218 0.445 0.589 0.674 0.441 -0.140

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Note large shifts between nominal (tv) and cold (tvc) or bits. No significant relative motion during shake test (between pre and post environmental tests) Global shift means cannot know if it occurs in target exposure for WF2 Is not associated with significant coma changes (>0.01 microns rms)

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(Q) M,NillfUTE

WFPC2 Optical Test Results

User's Committee Chris Burrows 28-May-1 993 12

Camera to camera pointing variations
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Seen both in target images and K-spots Occurs in WF2 K-s pots - Not j ust the AFM tem perature effect Tem perature change on bench of 1-2 degrees Makes astrometry between chips very hard Unlikely to affect single ex posures - images were stable at given orbital condition. Differential effect is about 0.5 pixels

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WFPC2 Optical Test Results

User's Committee Chris Burrows 28-May-1993 13

Conclus ions
Spherical aberration well corrected. Coma is correctable Some small astigmatism Significant focus differences between cameras Camera boresights stable at given bench temperature, but change relatively by about 0.5 pixels with 1-2 C tem perature change. Mechanisms appear to be stable between exposures at 0.3 pixel level Short term sta bility of mechanisms not tested because of stimulus vi brations.

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