MAESTRO Sun Scan Analysis

Florian NichitiuMay 14, 2004

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. 2004The 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-orbit dispersion equations, absolute sensitivity using High Sun measurements

Closed Loop offset sun-pointing parameters using High Sun Scan measurements

Sun ScanSun tracker in Open Loop

0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18

-1.00

-0.98

-0.96

-0.94

-0.92

-0.90

-0.88

-0.86

-0.84

Delta(T)=35.5 sec

High Sun ( just before Sun Scan EL-az )

(NIR)Ximag=65.21(NIR)Yimag=60.29

CL_AZoffset=1250CL_ELoffset=450

EL

(M

ec)

AZ (Mec)0.36 0.38 0.40 0.42 0.44 0.46

-1.18

-1.16

-1.14

-1.12

-1.10

-1.08

-1.06

-1.04

Delta(T)=35.5 sec

(NIR)Ximag=65.23(NIR)Yimag=60.29

CL_AZoffset=1250CL_ELoffset=450

High Sun ( just before Sun Scan AZ only)

EL

(M

ec)

AZ (Mec)

S/C motion during High Sun

Sun tracker on Closed Loop

High Sun spectra

Sun tracker in Closed Loop

0 50 100 150 200 250

2500000

2600000

2700000

2800000

2900000

3000000

3100000

3200000

3300000

3400000

Up to = 1078429778.014000

Unix Time=1078429553.394000

Pre

ad

Int S

pe

ctra

(U

V fr

om

pix

:50

1 to

10

00

)

Time (sec) from : 1129146353.394000

Int Table 23

Occultation

High Sun

Occultation

Bg. (dark current)

0 10 20 30 40 50 602500000

2600000

2700000

2800000

2900000

3000000

3100000

3200000

3300000

3400000

SP

Inte

gra

l (U

V p

rere

ad

)

Relative Time

UVaz IntelPaz IntUVel IntUVelMaz Int High Sun

Sun Scanning (Open Loop)

0 50 100 150 200-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

-1.75-2.00

0.05-0.20

2.662.41

EL

EL-az

EL+az

OPT AZ during elevation Sun Scan

OP

T A

Z (

mra

d)

Relative Time

0 50 100 150 200-4.0

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

-3.14

-2.67

Relative Time

OPT EL during AZ-Sun Scan

OP

T E

L (

mra

d)

Sun Scanning (Open Loop) : sun scan in azimuth (elevation) with elevation(azimuth) fixed

0 1 2 3 4 5 6 7 8 93.00

3.05

3.10

3.15

3.20

3.25

3.30

3.35

3.40

EL+azEL+az

ELEL

AZ AZEL-az EL-az

SP

IN

T (

10

^6)

NR of Sun Scan

UV1 UV2 HS

0 1 2 3 4 5 6 7 8 9-0.10

-0.09

-0.08

-0.07

-0.06

-0.05

-0.04

-0.03

-0.02

-0.01

0.00

0.01

EL+az

EL

AZ

EL-az AZEL-az

EL+az

EL

(Int(SS)-Int(HS))/Int(HS)

Y A

xis

Titl

e

X Axis Title

First Scan Second Scan

Maximum of spectrum integral during Sun Scan

-10 -5 0 5 10 152500000

2600000

2700000

2800000

2900000

3000000

3100000

3200000

3300000

3400000AZ Solar Scan First ( EL=-2.67)

Y A

xis

Titl

e

OPT Az (mrad)

UVaz

0.2

0.4

0.6

0.8

1.0

1.2

1.4

Center: FTS T=+0.35 mrad MAESTRO T=-1.21 mrad

mct

-6 -4 -2 0 2 4 6

0.0

0.2

0.4

0.6

0.8

1.0

AZ=-0.21176

MAESTRO First Scan in EL

OPT EL

Inte

gra

l (N

orm

aliz

ed

)

Data: visElA_visModel: LimbDark Chi^2 = 0.00002R^2 = 0.99974 P1 1.00002 ±0.00169P2 1 ±0P3 4.60657 ±0.01586P4 -0.98823 ±0.00422P5 1.46745 ±0.02264

EL=-0.98823

vis

30 40 50 60 702500000

2600000

2700000

2800000

2900000

3000000

3100000

3200000

3300000

Center: FTS T=48.57 sec MAESTRO T=48.57 sec

EL Solar Scan Second ( AZ=0.05)

Time (sec)

IntUVel

0.2

0.4

0.6

0.8

1.0

1.2

1.4 mct

Hestroffer Solar Limb Darkening. model:(Atron. Astrophys 333,338-342(1998))

-14 -12 -10 -8 -6 -4 -2 0 2 4 6

0.0

0.2

0.4

0.6

0.8

1.0

EL-az Solar Scan II

Nor

m In

t

OPTel (mrad)

UVint VISint

0.5 1.0 1.5 2.0 2.5 3.0

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

Diff. in widths

(UofT test: 0.261 mrad)

EL-az Solar Scan II

0.26 mrad

OPTel (mrad)N

orm

Int

VISint UVint

UV=0.26 mrad

VIS

20 30 40 50 60 70 80 90 10085

80

75

70

65

60

55

50

45

[C]

[B]

[A]

NIR sunscan

ima

ge

r y

axi

s

imager x axis

-12 -10 -8 -6 -4 -2 0 2 4 6 8 102500000

2600000

2700000

2800000

2900000

3000000

3100000

3200000

3300000

[C]

[B]

[A]

Diff/Max=0.0125

-0.933

9.2 mrad

Solar Scan in elevation UV spectra

Co

un

ts

Optical EL (mrad)

EL #1 EL #2

Solar Scan in elevation 21 Feb. 2004

Solar Disk dimension

as expected:Solar disk radius = 4.6 mrad

45 50 55 60 65 70 75 80 85

30

40

50

60

70

80

NIR

ima

ge

r Y

NIR imager X

Edges: at Max Deriv. Edges: at 1/2Max DFLtest before flight

0 10 20 30 40 50 60

-100000

-80000

-60000

-40000

-20000

0

20000

40000

60000

80000

100000 Az scan IIAz scan I

Differentiate

Time

UVaz'

2500000

2600000

2700000

2800000

2900000

3000000

3100000

3200000

3300000

3400000

UVaz

0 5 10 15 20 252500000

2600000

2700000

2800000

2900000

3000000

3100000

3200000

3300000

3400000Az scan I

Int

Time

UVaz

30 35 40 45 50 55 602500000

2600000

2700000

2800000

2900000

3000000

3100000

3200000

3300000

3400000 Az scan II

Int

Time

UVaz

Using time as parameter Sun centroid in Imag coordinates

20 30 40 50 60 70 80 90 100 110

100

90

80

70

60

50

40

30NIR imager

de

tect

or

y a

xis

detector x axis

Slit VIS-spectrometer Slit UV-spectrometer Sun Scan in EL-az Sun Scan in AZ

20 30 40 50 60 70 80 90 100 110

100

90

80

70

60

50

40

30 NIR imager

detector x axis (pixels)

de

tect

or

y a

xis

(pix

els

)

NIRySS-VIS NIRySS-UV NIRyUVDFL NIRyVISDFL

Slit position on the NIR imager : - Sun Scan analysis - DFL: final test

125

120

115

110

105

100

95908580757065605550454035302520151050

125

120

115

110

105

100

95

90

85

80

75

70

65

60

55

50

45

40

35

30

25

20

15

10

5

0 20 40 60 80 100 120

120

100

80

60

40

20

0

detector x axis (pixels)

dete

ctor

y a

xis

(pix

els)

NIRy UV NIRy VIS

Slit position on the NIR imagerand Sun position during CL

250 300 350 400 450 500 550 600

5200

5400

5600

5800

6000

6200

6400

6600

6800

7000

Wavelength [nm]

Co

un

ts

Maestro UV SM20

300 350 400 450 500 550 6000.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

2.2

Wavelength [nm]

Solar Spectra 20 point AA Smoothing of SolarSp_B

Maestro spectra vs. Solar Spectra

300 320 340 360 380 400

-20

-10

0

10

20

30

Diff Maestro UV

Wavelength [nm]

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

Diff Solar Spectra

400 420 440 460 480 500-100

-50

0

50

100

150

Diff Maestro UV

Wavelength [nm]

-0.4

-0.2

0.0

0.2

0.4

0.6

Diff Solar Spectra

500 510 520 530 540 550 560 570-80

-60

-40

-20

0

20

40

60

Wavelength [nm]

Diff Maestro UV

-0.15

-0.10

-0.05

0.00

0.05

0.10

0.15

0.20

Diff Solar Spectra

Dispersion eq. For calculating wavelength (nm) from pixel number: Wavelength=-1.0261e-8*p^3-9.5161e-6*p^2+0.32629*p+254.98(From UofT Evaluation Test)

Difference between smoothing and Exp. spectra.

There is a shift in Wavelength ~ 3.43 nm

400 420 440 460 480 500-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

Wavelength [nm]

A Solar Spectra

-150

-100

-50

0

50

100

150

Diff Maestro UV

400 420 440 460 480 500-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

Wavelength [nm]

A Solar Spectra

-150

-100

-50

0

50

100

150

Diff Maestro UV

Data from: “Solar Flux Atlas…NSO/Kitt Peak : ftp://ftp.noao.edu/fts

0 200 400 600 800 1000 12005.0

5.5

6.0

6.5

7.0

7.5

Average of 37 spectra

Average of 39 spectra

UV High Sun Spectra

Co

un

ts *

10

00

Pixel #

SP DK

540 560 580 600 620 640 660 680 700 720-100

-50

0

50

100

150

Pixel #

DiffMAE

-0.10

-0.05

0.00

0.05

0.10

0.15

DiffUVcor

UV spectra from Sun Scan 21 Feb 2004UV spectra from High Sun 14 Apr 2005

MAESTRO spectra ‘Stability’

500 550 600 650 700 750-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

Pixel #

DiffSol

-150

-100

-50

0

50

100

150

DiffMAE

0 200 400 600 800 1000 1200-0.05

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

Solar(ATLAS1) / MAEuv

Pol(3)

Pol(6)

So

lar(

AT

LA

S1)

/ M

AE

uv

Pixel #

New dispersion equation for wavelength Pixel (UV spectra):

WL=-1.0261e-8*p^3-9.5161e-6*p^2+0.32629*p+251.55

P=-747.50757+2.85456*WL+7.20263e-4*WL^2-1.45118E-6*WL^3+1.88693E-9*WL^4

‘correction’ of UV spectra for each pixel: From counts to micro-watts per square centimeter per nanometerData at each ~0.05 nm averaged for ~0.3 nm ( as UV Maestro at ~ 400 nm)

500 550 600 650 700 750

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

Diff for Solar Spectra

Pixel #

-200

-150

-100

-50

0

50

100

150

200UV

Diff MAE

150 200 250 300 350-0.25

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

VIS

Pixel #

Diff for Solar Spectra

-40

-20

0

20

40

60

Diff MAE

L(VIS)=-2.1254e-8*p^3-8.6224e-6*p^2+0.52626*p+514.23Correct Lambda=L(VIS)-6.08 nmP(Vis)=-932.00736+1.7112*L+4.47888e-4*L^2-5.78258e-7*L^3+3.41003e-10*L^4

L(UV)=-1.0261e-8*P^3-9.5161e-6*P^2+0.32629*P+254.98Correct Lambda=L(UV)-3.43 nmP(UV)=-748.06497+2.85457*L+7.20675e-4*L^2-1.453e-6*L^3+1.88785e9*L^4

0 200 400 600 800 1000 1200

-100

0

100

200

300

400

500

Pixel #

VISmae

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

SM20v

0 200 400 600 800 1000 1200

-50

0

50

100

150

200

250

300

350 VIS

Se

nsi

tivity

(F

rom

Uo

fT L

ab

Te

st)

Se

nsi

tivity

(F

rom

So

lar

Sp

ect

ra)

Pixel #

MAEonSOLvis

0.00E+000

1.00E+008

2.00E+008

3.00E+008

4.00E+008

5.00E+008

6.00E+008

7.00E+008

UofT test

MAESTRO VIS spectrometer absolute sensitivity

Units: (counts/s)/(Wm^-2nm^-1)

0 200 400 600 800 1000 1200-500

0

500

1000

1500

2000

Pixel #

UVmae

0

2

SM20uv

200 400 600 800 1000-200

0

200

400

600

800

1000

Se

nsi

tivity

(F

rom

Uo

fT L

ab

Te

st)

Se

nsi

tivity

(F

rom

So

lar

Sp

ect

ra)

Pixel #

MAEonSolUV

0.00E+000

2.00E+008

4.00E+008

6.00E+008

8.00E+008

1.00E+009

1.20E+009

1.40E+009

1.60E+009UV UofT test

MAESTRO UV spectrometer absolute sensitivity

Units: (counts/s)/(Wm^-2nm^-1)

MAESTRO HIGH SUN scan

45 measurements with different sun tracker pointing positionsUsing Closed Loop offsets in azimuth and elevation (including the Standard CL offsets to the center of the High Sun : CL_AZ=1250; CL_EL=450)

CL_AZ=1750

CL_AZ= 750

CL_EL= -50 CL_EL=950

20 30 40 50 60 70 80 90 100 110

100

90

80

70

60

50

40

30NIR imager

dete

ctor

y a

xis

detector x axis

Slit VIS-spectrometer Slit UV-spectrometer Sun Scan in EL-az Sun Scan in AZ

0 100000 200000 300000 400000 500000 6000005100000

5150000

5200000

5250000

5300000

5350000

5400000

5450000

5500000

VIS High Sun Scan

To

t N

r o

f co

un

ts

Seconds 0 100000 200000 300000 400000 500000 600000

2500000

2600000

2700000

2800000

2900000

3000000

3100000

3200000

3300000

UV High Sun Scan

Seconds

To

t N

r o

f co

un

ts

Spectrum integral during High Sun Scan

Bg. ( spectrum integral for pointing ‘out of Sun’

0 100000 200000 300000 400000 500000 600000

3180000

3200000

3220000

3240000

3260000

UV High Sun

(~0.75 %)

(EL=450; AZ=1250)

(EL=450; AZ=1750)

Tot

_Nr_

Cou

nts

Seconds

0 100000 200000 300000 400000 500000-0.002

-0.001

0.000

0.001

0.002

0.003

0.004

Average val=3.23937E6

(Tot

_Nr_

of_c

ount

s-A

vera

ge)/

Ave

rage

Seconds

High Sun "Standard"A 2.57296E6 523.06589B 1.11479E-4 0.00154

0 200000 400000-4

-3

-2

-1

0

1

(From 14/04/2004)

MA

E_

TH

M_

SP

EC

_T

OP

(C

)

Seconds

TempTop

3234000

3236000

3238000

3240000

3242000

3244000

3246000

3248000

3250000

High Sun "Standard"

0 100000 200000 300000 400000 5000005468000

5470000

5472000

5474000

5476000

5478000

5480000

5482000

Seconds

To

t N

r o

f co

un

ts

To

t N

r o

f co

un

ts

Standard High Sun VIS

3234000

3236000

3238000

3240000

3242000

3244000

3246000

3248000

3250000

UV

0 100000 200000 300000 400000 500000 600000

-0.002

-0.001

0.000

0.001

0.002

0.003

0.004

0.005

(Tot

_Nr_

of_c

ount

s-A

vera

ge)/

Ave

rage

Seconds

Off Sun (Bg)Aerage = 2.57299E6

0 100000 200000 300000 400000 500000 600000

-0.002

-0.001

0.000

0.001

0.002

0.003

0.004

0.005

(Tot

_Nr_

of_c

ount

s-A

vera

ge)/

Ave

rage

Seconds

BG HS

Bg. High Sun

350000 400000 450000 500000 5500003180000

3190000

3200000

3210000

3220000

3230000

3240000

3250000

3260000

UV High Sun Scan

Seconds

"Standard" HS

To

t Nr

of

cou

nts

UV

300000 350000 400000 450000 500000 5500003180000

3190000

3200000

3210000

3220000

3230000

3240000

3250000

3260000

Tot

Nr

of c

ount

s

High Sun Scan

Seconds

UV

5460000

5462000

5464000

5466000

5468000

5470000

5472000

5474000

VIS

600 800 1000 1200 1400 1600 18003180000

3190000

3200000

3210000

3220000

3230000

3240000

3250000

3260000

"Standard" HS

UV High Sun Scan

To

t Nr

of c

ou

nts

Closed Loop AZ

UV

-200 0 200 400 600 800 1000800

1000

1200

1400

1600

1800

2000

2200

2400

xel

yaz

3.06178016e+000+4.82389927e-005 xel-...-008 yaz2

2D fit ( polynomial second degree in CL_AZ and CL_EL)

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 parametersand we propose a new set of these parameters which can improve the quality of measurements. CL_AZ_offset = 1750 ( max) CL_EL_offset = 355

Acknowledgements:

James Drummond

Tom McElroy

Denis Dufour

Caroline Nowlan

Kathleen Gilbert

Sean D McLeod

Jay Kar

Jason Zou

Clive Midwinter