1. J.P. Halain – Centre Spatial de Liège
HI straylight performances Design, pre-flight test data and in flight results
J.P. Halain – Centre Spatial de Liège
with J.M. Defise, E. Mazy, A Mazzoli - CSL (Belgium)
D Moses, J Newmark, C Korendyke, D Socker - NRL (US)
C. Eyles, R. Harrison, C Davis UB, RAL (UK)
March 2007
SECCHI Consortium Meeting - Paris

2. SECCHI Consortium Meeting - Paris
Summary
HI Instrument concept
Main challenges
HI Straylight requirements
Instrument design (diffractive and reflective baffles)
HI pre-flight performance measurements
Spot and photometry results
Sun-limb, off-pointing and out-FOV straylight results
HI preliminary in-flight straylight results
Off-pointing results
Straylight pattern analysis
In and out-FOV results
March 2007
SECCHI Consortium Meeting - Paris

3. SECCHI Consortium Meeting - Paris
HI Instrument Concept
Main challenges:
Faint detection capability (10-15 B0)  high stray-light rejection requirements
Large FOV  specific optics
Solar light
Forward Baffle
Internal Baffle
HI 1
HI 2
March 2007
SECCHI Consortium Meeting - Paris

4. HI Straylight Requirements
Major stray-light contributors
Direct solar light (B0 !)
Bright sources in and out FOV (Earth)
Payload elements near the UFOV
Background composed of F-corona, planets, stars, Earth and moon
Stray-light requirements
Instrument background straylight requirements:
< 3x10-13 B/B0 for HI-1
< B/B0 for HI-2
HI-1
HI-2
March 2007
SECCHI Consortium Meeting - Paris

5. HI Design – Forward Baffle
Front baffle concept with the location of the HI-1 & 2 optical systems
Intensity profiles measured with the 5-knive edge mock up
in air and in vacuum,
HI cascading knives-edges forward baffle computed efficiency
March 2007
SECCHI Consortium Meeting - Paris

6. HI Design – Internal Baffle
Internal baffle ray-tracing model
Computed performance at HI-2 entrance (log)
Straylight level in HI-1 and HI-2 (nominal orbit)
March 2007
SECCHI Consortium Meeting - Paris

7. HI pre-flight performance measurement
HI-A and HI-B flight models optical performances and end-to-end straylight verification NB: instrument axis at 3.65-arcdeg
HI instrument
Black enclosure
Light source collimator
March 2007
SECCHI Consortium Meeting - Paris

8. Pre-flight: HI-A In-field results
HI-A spot measurements : (1 px = 13.5µm)
38.8µm < HI-1 RMS spot diameter < 54.3µm
31.5µm < HI-2 RMS spot diameter < 78.1µm
Design values:
45µm < HI-1 < 67µm
105µm < HI-2 < 145µm
Half Energy Spot Width [µm]
NB: - photometry results of HI-A pre-flight calibration are limited by smearing
- straylight results are limited by chamber background
March 2007
SECCHI Consortium Meeting - Paris

9. Pre-flight: HI-B In-field results
HI-B spot measurements : (1 px = 13.5µm)
37.9µm < HI-1 RMS spot diameter < 49.8µm
68.6µm < HI-2 RMS spot diameter < 164.8µm (border of FOV)
Design values:
45µm < HI-1 < 67µm
105µm < HI-2 < 145µm
Half Energy Spot Width [µm]
HI-B Photometry
HI-1B detector conversion:
HI-2B detector conversion:
March 2007
SECCHI Consortium Meeting - Paris

10. Pre-flight: HI-1B straylight (sun limb)
Straylight verification with reference black panels and collimated laser
Super Black Panel
130DN = 3∙10-13 B/B0
(at requirement level)
Underscan columns = 126 DN
B0 = DN = ph
720s integration time
Laser Beam
(B0)
133DN = 5∙10-13 B/B0
127DN = B/B0
Curtain Edge
HI-1B image
March 2007
SECCHI Consortium Meeting - Paris

11. Pre-flight: HI-1B straylight (off-pointing)
5∙10-13 B/B0
7.5∙10-13 B/B0
3∙10-13 B/B0
Ring appears
4∙10-11 B/B0
8∙10-12 B/B0
1.2∙10-11 B/B0
0.17
0.33
2∙10-9 B/B0
4∙10-12 B/B0
1.2∙10-12 B/B0
5∙10-7 B/B0
1.8∙10-10 B/B0
10-9 B/B0
0.5
0.66
1.0
March 2007
SECCHI Consortium Meeting - Paris

12. Pre-flight: HI-1B straylight (1-arcdeg)
Ring pattern dominate diffractive pattern in HI-1 straylight
Diffractive pattern
Ring pattern
Detail of HI-1B image , with collimated beam at 1.5-arcdeg from sun-limb direction
March 2007
SECCHI Consortium Meeting - Paris

13. Pre-flight: HI-1B straylight (diffraction)
3.6∙10-11 B/B0
5∙10-7 B/B0
Detail of HI-1B image , with collimated beam at 1.5-arcdeg from sun-limb direction
March 2007
SECCHI Consortium Meeting - Paris

14. Pre-flight: HI-1B straylight (out FOV)
Various offset angles at border of HI-1 FOV (3.65 – arcdeg)
Ring pattern visible + other ghosts
In FOV
2.5
3.5 4
4.5 5
4.1∙10-8 B/B0
5∙10-8 B/B0
4.6∙10-8 B/B0
5.5∙10-8 B/B0
4.6∙10-9 B/B0
1.5∙10-7 B/B0 24 25 26 27 30
4.2∙10-8 B/B0
3∙10-8 B/B0
4∙10-8 B/B0
2.4∙10-8 B/B0
1.1∙10-8 B/B0
March 2007
SECCHI Consortium Meeting - Paris

15. Pre-flight: HI-2B straylight (sun limb)
At Requirement level:
1.2∙ B/B0
Super Black Panel
Super Black Panel
1.2∙ B/B0
Laser Beam
(B0)
Earth occulter
1.5∙ B/B0
Black enclosure
HI-2B image
March 2007
SECCHI Consortium Meeting - Paris

16. Pre-flight: HI-1&2B (sun limb)
Laser Beam
(B0)
Combination of HI-1B and HI-2B images
March 2007
SECCHI Consortium Meeting - Paris

17. Pre-flight: HI-2B straylight (out FOV)
Various offset angles at border of HI-2 FOV (18.36 – arcdeg)
Internal baffle illuminated + ghosts
4.3∙10-8 B/B0
2.7∙10-8 B/B0
1.2∙10-10 B/B0
2.6∙10-8 B/B0 10 15 90
1.7∙10-8 B/B0
6.4∙10-10 B/B0
4.5∙10-10 B/B0
4.3∙10-8 B/B0
100
120
140
March 2007
SECCHI Consortium Meeting - Paris

18. First Flight Image – HI-1A
13-Dec-2006
Approximate
Location of
Sun
Ecliptic Plane
F-Corona
Symmetric with Ecliptic
March 2007
SECCHI Consortium Meeting - Paris

19. First Flight Image – HI-2A
13-Dec-2006
Inner Baffle
Illuminated by
Earthshine
Approximate
Location of
Sun
Earth Occulter
Ecliptic Plane
F-Corona
Symmetric with Ecliptic
March 2007
SECCHI Consortium Meeting - Paris

20. In-flight: HI-1A & B straylight (off pointing)
Off-pointing 10-Jan-07 and 13-Jan-07
HI-1A
1.2∙10-12 B/B0
1.1∙10-11 B/B0
> 5∙10-10 B/B0
1.0
1.5
HI-1B
2∙10-12 B/B0
1.2∙10-11 B/B0
4.8∙10-10 B/B0
1.0
1.5
March 2007
SECCHI Consortium Meeting - Paris

21. In-flight: HI-1A straylight (off pointing)
Off-pointing 30-Jan-07
9.8∙10-12 B/B0
5.3∙10-13 B/B0
8.2∙10-13 B/B0
4∙10-12 B/B0
3.5∙10-12 B/B0
5∙10-12 B/B0
0.24
0.5
1∙10-12 B/B0
1.9∙10-12 B/B0
7.9∙10-11 B/B0
6∙10-12 B/B0
1.1∙10-11 B/B0
5∙10-10 B/B0
0.75
1.0
1.5
March 2007
SECCHI Consortium Meeting - Paris

22. In-flight: HI-1 straylight comparison
March 2007
SECCHI Consortium Meeting - Paris

23. In-flight: HI-1A straylight (1.5-arcdeg)
2∙10-10 B/B0
Diffractive pattern
7.9∙10-11 B/B0
Ring pattern
> 5∙10-10 B/B0
1.5
Similar combination of diffractive and ring pattern as
(instrument pointing during tests arcdeg vs. in flight pointing arcdeg)
March 2007
SECCHI Consortium Meeting - Paris

24. HI-1 straylight: ring pattern analysis
Ray-tracing model of HI-1 lens barrel shows that the 2 last retainers generate the ring pattern
FOV border
(3.65-arcdeg)
FOV border - 3 arcdeg
(0.65-arcdeg)
March 2007
SECCHI Consortium Meeting - Paris

25. HI-1 straylight: ring pattern analysis (2)
FOV border - 7 arcdeg
FOV border - 10 arcdeg
FOV border - 15 arcdeg
FOV border - 20 arcdeg
March 2007
SECCHI Consortium Meeting - Paris

26. In-flight: HI-1 straylight (out-FOV)
Earth arriving close to the HI-1B FOV on beg. February 07 (before entering in FOV) confirms the preliminary analysis of ring pattern (no diffractive pattern in the ring) 30 26
HI-1 B (1-Feb-07)
HI-1 B (3-Feb-07)
March 2007
SECCHI Consortium Meeting - Paris

27. In-flight: HI-1 straylight in-FOV
Similar ring straylight pattern with a bright star (in FOV), probably due to other similar parts of the lens barrel (ghost). TBC.
1.3∙10-12 B/B0
> 2∙10-9 B/B0
March 2007
SECCHI Consortium Meeting - Paris

28. In-flight: HI-2 straylight (out-FOV)
The 5 oval edges are in the FOV and imaged.
Preliminary explanation is Earth close behind instrument and illuminate internal baffles from rear
HI-2 A (13-Dec-06)
HI-2 B (15-Jan-07)
88,425
March 2007
SECCHI Consortium Meeting - Paris

29. In-flight: HI-2 straylight (in and out FOV)
Earth crossed HI-2B FOV beg. of February
140
120
100 90 80 50 20 10
In FOV
Earth behind instrument is not the only straylight sources in HI-2 (SWAVES boom ?)
March 2007
SECCHI Consortium Meeting - Paris

30. SECCHI Consortium Meeting - Paris
Conclusions
Preliminary straylight comparisons
In-flight straylight / ghosts are qualitatively similar to the pre-flight measurements
Comparable sun limb straylight level in HI-1, but lower in-flight off-pointing values
Ring pattern in HI-1 preliminary analysis result
Work plan for CSL
Continue HI-1 and HI-2 in-field and at border of FOV analysis
Straylight quantitative results to be continued and refine (additional off-pointing)
Earth and SWAVES boom effect in HI-2 to be confirmed when Earth will be further
Comparison of HI-2 straylight with Earth-S/C-Sun angle
Ghosts and straylight to be re-evaluated when in nominal orbit with Earth far enough
In-flight calibration and F-Corona removal for straylight analysis results improvement
Instrument other performances analysis
Compare PSF to have a model of PSF for de-convolution
Characterize PSF as function of position in CCD
Characterize distortion for correction
March 2007
SECCHI Consortium Meeting - Paris

31. SECCHI Consortium Meeting - Paris
Back-up slides
March 2007
SECCHI Consortium Meeting - Paris

32. Pre-flight: HI-1A straylight (0-arcdeg)
Beam
(B0)
2.1x10-10 B/B0
2x x10-10 B/B0
7.1x10-11 B/B0
March 2007
SECCHI Consortium Meeting - Paris

33. Pre-flight: HI-2A straylight (0-arcdeg)
Beam
(B0)
2x10-10 B/B0
4x x10-12 B/B0
March 2007
SECCHI Consortium Meeting - Paris