MAESTRO Sun Scan Analysis

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MAESTRO Sun Scan Analysis
Florian Nichitiu May 14, 2004
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After on-orbit commissioning of the spacecraft
and instruments a series of on-orbit
science-oriented activities have been
undertaken. Sun Scanning (Open Loop)
21 Feb. 2004 High Sun Scanning (Closed
Loop) 14 17 Apr. 2004 The purpose of these
activities is to - extend and verify the
results obtained during pre-launch lab-tests -
to find the appropriate parameters for
operational measurements.
?MAESTRO field of
view characterization, UV and VIS slit position,
using Sun Scan measurements. ?On-orbi
t dispersion equations, absolute sensitivity
using High Sun measurements ?Closed
Loop offset sun-pointing parameters
using High Sun Scan measurements
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Sun Scan Sun tracker in Open Loop
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S/C motion during High Sun
Sun tracker on Closed Loop
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High Sun spectra
Sun tracker in Closed Loop
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Occultation
? High Sun
? Occultation
? Bg. (dark current)
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Sun Scanning (Open Loop)
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Sun Scanning (Open Loop) sun scan in azimuth
(elevation) with
elevation(azimuth) fixed
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Maximum of spectrum integral during Sun Scan
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Hestroffer Solar Limb Darkening. model (Atron.
Astrophys 333,338-342(1998))
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0.26 mrad
VIS
UV
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Solar Disk dimension
Solar Scan in elevation 21 Feb. 2004
as expected Solar disk radius 4.6 mrad
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Using time as parameter ? Sun centroid in Imag
coordinates
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Slit position on the NIR imager - Sun Scan
analysis - DFL final test
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Slit position on the NIR imager and Sun position
during CL
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Maestro spectra vs. Solar Spectra
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Difference between smoothing and Exp. spectra.
Dispersion eq. For calculating wavelength (nm)
from pixel number Wavelength-1.0261e-8p3-9.51
61e-6p20.32629p254.98 (From UofT Evaluation
Test)
There is a shift in Wavelength 3.43 nm
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Data from Solar Flux AtlasNSO/Kitt Peak
ftp//ftp.noao.edu/fts
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MAESTRO spectra Stability
UV spectra from Sun Scan 21 Feb 2004 UV spectra
from High Sun 14 Apr 2005
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New dispersion equation for wavelength ?? Pixel
(UV spectra) WL-1.0261e-8p3-9.5161e-6p20
.32629p251.55 P-747.507572.85456WL7.20263e-
4WL2-1.45118E-6WL31.88693E-9WL4
correction of UV spectra for each pixel From
counts to micro-watts per square centimeter per
nanometer Data at each 0.05 nm ? averaged for
0.3 nm ( as UV Maestro at 400 nm)
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L(UV)-1.0261e-8P3-9.5161e-6P20.32629P254.9
8 Correct LambdaL(UV)-3.43 nm P(UV)-748.064972.
85457L7.20675e-4L2-1.453e-6L31.88785e9L4
L(VIS)-2.1254e-8p3-8.6224e-6p20.52626p514.
23 Correct LambdaL(VIS)-6.08 nm P(Vis)-932.00736
1.7112L4.47888e-4L2-5.78258e-7L33.41003e-1
0L4
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MAESTRO VIS spectrometer absolute sensitivity
Units (counts/s)/(Wm-2nm-1)
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MAESTRO UV spectrometer absolute sensitivity
Units (counts/s)/(Wm-2nm-1)
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MAESTRO HIGH SUN scan

45 measurements with different sun tracker
pointing positions Using Closed Loop offsets in
azimuth and elevation (including the Standard CL
offsets to the center of the High Sun
CL_AZ1250 CL_EL450)
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CL_AZ1750 CL_AZ 750
CL_EL -50 CL_EL950
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Spectrum integral during High Sun Scan
Bg. ( spectrum integral for pointing out of Sun
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Bg. ? ? High Sun
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2D fit ( polynomial second degree in CL_AZ and
CL_EL)
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Conclusions

• From Sun Scan we find a good agreement
• For VIS and UV slit position and dimension
• with pre flight test.
• Corrections for VIS and UV
• -New dispersion equation (pixel? ? wave length)
  .
• -New spectrometer absolute sensitivity.
• From High Sun Scan we confirm the appropriate
• Closed Loop Offsets parameters
• and we propose a new set of these parameters
  which
• can improve the quality of measurements.
• CL_AZ_offset 1750 ( max)
• CL_EL_offset 355

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Acknowledgements
James Drummond Tom McElroy
Denis Dufour Caroline Nowlan
Kathleen Gilbert
Sean D McLeod
Jay Kar Jason
Zou Clive
Midwinter