1.0 COOLDOWN #1 (16.07.97 - 25.07.97)

1.1 Detector

1.1.1 Degradation of engineering grade #2

1.1.2 Noise

1.1.3 Dark current measurement

1.2 Optics

1.2.1 Focus with star simulator.

1.2.2 Polarimetry:

1.2.3 Low resolution spectroscopy

2.0 COOLDOWN #2 (05.97 - 05.08.97)

2.1 General

2.2 Mechanics and control of functions

2.3 Focus curve with collimator

2.3.1 Spectroscopy objective SO

2.3.2 Large field objective LF

2.4 Conclusions

3.0 COOLDOWN #3

4.0 COOLDOWN #4

4.1 Pixel Transfer Function

4.2 Image Quality SF

5.0 COOLDOWN #5 (29.9.1997-)

5.1 Detector alignment:

5.2 Flexure

6.0 COOLDOWN #6

7.0 COOLDOWN #7

7.1 Flexure

7.2 Pixel Transfer Function

7.3 Efficiency

7.4 Image Quality of objective LF

TABLE 1. magnification of SOFI objectives

TABLE 2. Narrow band filter and center pixel

TABLE 3. Focus position of collimator for spectroscopy objective SO

TABLE 4. Detector rotation normal to optical axis

TABLE 5. Detector rotation normal to optical axis

TABLE 6. Peak to Peak flexure of SOFI

TABLE 7. Peak to Peak flexure of SOFI with and without external force

TABLE 8. Conversion factor and amplifier gain

TABLE 9. Total efficiency of SOFI in imaging mode

TABLE 10. Efficiency of red grism

FIGURE 1. Original cosmetic quality of Rockwell 1024x1024 engineering grade #2

FIGURE 2. Cosmetic quality of Rockwell 1024x1024 engineering grade #2 mounted in ISAAC.

FIGURE 3. Cosmetic quality of Rockwell 1024x1024 engineering grade #2 mounted in SOFI.

FIGURE 4. Noise of Hawaii engineering grade #2 in SOFI. The shot noise

FIGURE 5. Dark frames versus time at a temperature of 108 K.

FIGURE 6. Dark frames versus time at a temperature of 78 K. Dark current is less than 26 e/sec

FIGURE 7. Focus curve for objective SF with narrow band filter 2.28 mm. Squares: averaged FWHM. Dots: FWHM in x direction. Triangles: FWHM in y direction.

FIGURE 8. Image quality of objective SF with narrow band filter 2.28 mm.

FIGURE 9. Focus curve for objective SO with narrow band filter 2.28 mm. Squares: averaged FWHM. Dots: FWHM in x direction. Triangles: FWHM in y direction.

FIGURE 10. Image quality of objective SO with narrow band filter 2.28 mm.

FIGURE 11. Focus curve for objective SO and FE with narrow band filter 2.28 mm. Squares: averaged FWHM. Dots: FWHM in x direction. Triangles: FWHM in y direction.

FIGURE 12. Image quality of objective SO an FE with narrow band filter 2.28 mm. Position of star simulator 360000 encoder steps.

FIGURE 13. Fiber image taken in polarimetry mode. Separation of images with SF is 331 pixels.

FIGURE 14. Intensity of ordinary and extra-ordinary ray image as function of ploarization angle.

FIGURE 15. Ne Spectrum taken with blue grism and star simulator.

FIGURE 16. Focus curve for objective SO with narrow band filter at l=1.083mm. Squares: averaged FWHM. Dots: FWHM in x direction. Triangles: FWHM in y direction. Direction of collimator position is positive pointing from slit towards collimator.

FIGURE 17. Focus curve for objective SO with narrow band filter at l=1.644mm. Squares: averaged FWHM. Dots: FWHM in x direction. Triangles: FWHM in y direction. Direction of collimator position is positive pointing from slit towards collimator

FIGURE 18. Focus curve for objective SO with narrow band filter at l=2.17 mm. Squares: averaged FWHM. Dots: FWHM in x direction. Triangles: FWHM in y direction. Direction of collimator position is positive pointing from slit towards collimator

FIGURE 19. Image quality of SO with narrow band filter at l=1.644mm. 36% of total flux on 1 pixel. Fwhm 1.3 pixels. Center pixel 5770 ADU. Collimator position 4.212 mm (18000 encoder steps)

FIGURE 20. Focus curve for objective LF with narrow band filter at l=1.083 mm. Squares: averaged FWHM. Dots: FWHM in x direction. Triangles: FWHM in y direction. Direction of collimator position is positive pointing from slit towards collimator.

FIGURE 21. Focus curve for objective LF with narrow band filter at l=1.644 mm. Squares: averaged FWHM. Dots: FWHM in x direction. Triangles: FWHM in y direction. Direction of collimator position is positive pointing from slit towards collimator.

FIGURE 22. Focus curve for objective LF with narrow band filter at l=2.17 mm. Squares: averaged FWHM. Dots: FWHM in x direction. Triangles: FWHM in y direction. Direction of collimator position is positive pointing from slit towards collimator.

FIGURE 23. Detector position at cooldown #2. Best focus position of collimator 3400 mm. Distance detector-objective has to be increased by 1.16mm to bring focus to nominal position of collimator at -1.685 mm.

FIGURE 24. Image quality of LF objective with narrow band filter at l=1.083 mm. 5.5% of total flux on 1 pixel. Fwhm 3.7 pixels. Center pixel 575 ADU. Collimator position 4.212 mm (18000 encoder steps)

FIGURE 25. Pixel transfer function determined with shot noise method.

FIGURE 26. Efficiency of SOFI with narrow band filter at 2.288 mm and large field objective.

FIGURE 27. Noise of Hawaii science grade #1 in SOFI. Noise peaks at 6.4 electrons rms corresponding to a read-out noise of 4.5 electrons rms per read-out.

FIGURE 28. Pixel transfer function determined with shot noise method. Rise time 2 msec. Gain 3.

FIGURE 29. Focus curve for objective SF with narrow band filter 2.28 mm. Squares: averaged FWHM. Dots: FWHM in x direction. Triangles: FWHM in y direction.

FIGURE 30. Image quality of objective SF with narrow band filter 2.124 mm and filter K using pupil mask. FWHM 2.2 pixels. 14% of flux in one pixel.

FIGURE 31. Noise of Hawaii science grade #1 in SOFI. Noise peaks at 2.4 electrons rms corresponding to a read-out noise of 1.7 electrons rms per read-out. Gain 3. trise= 2 msec. Integration time 36 sec. Multiple sampling and least squares fitting of 32 nondestructive read-out.

FIGURE 32. Read-out noise and shot noise of Hawaii science grade #1 in SOFI versus integration time. Read-out noise per single nondestructive read-out 3.2 e rms. Darkcurrent 100 e/hour. Best conditions for integration time of 64 sec: measured noise of 2.2 erms is composed of read-out noise 1.75 e rms and shot noise of 1.33 e rms. Gain 24. trise= 2 msec. Multiple sampling and least squares fitting of 64 nondestructive redcoats.

FIGURE 33. Position of dummy as read on translator stage and alignment of crosshair

FIGURE 34. Position of dummy as read on translator stage and alignment of crosshair

FIGURE 35. Position of dummy as read on translator stage and alignment of crosshair. Vectors show displacement magnified 20 times.

FIGURE 36. Position of dummy as read on translator stage and alignment of crosshair. Vectors show displacement magnified 20 times.

FIGURE 37. Flexure of Sofi objective LF measured at 24 positions. Inner circle shows movement of point image on detector for one full revolution.Position of closed cycle cooler indicated on rotated squares as seen standing in front of entrance window. Flexure is 3.24 pixels peak to peak at detector or 174.5 mm at telescope focus pointing in opposite direction of gravity.

FIGURE 38. Flexure of Sofi objective SF with focal elongator measured at 24 positions.Inner circle shows movement of point image on detector for one full revolution. Position of closed cycle cooler indicated on rotated squares as seen standing in front of entrance window. Flexure is 11.61 pixels peak to peak at the detector or 156.05 mm at telescope focus pointing in opposite direction of gravity.

FIGURE 39. Flexure of Sofi objective LF and Wollaston prism measured at 24 positions. Inner circle shows movement of point image on detector for one full revolution. Position of closed cycle cooler indicated on rotated squares as seen standing in front of entrance window. Flexure is 3.22 pixels peak to peak at the detector or 173.42 mm at telescope focus pointing in opposite direction of gravity.

FIGURE 40. Internal flexure of Sofi objective SF and focal elongator measured at 24 positions. Inner curve shows movement of point image on detector for one full revolution. Position of closed cycle cooler indicated on rotated squares as seen standing in front of entrance window. Flexure is 4.26 pixels peak to peak at the detector or 57.25 mm at telescope focus pointing normal to direction of gravity.

FIGURE 41. Internal flexure of Sofi cold structure with objective LF measured at 24 positions. Inner curve shows movement of point image on detector for one full revolution. Position of closed cycle cooler indicated on rotated squares as seen standing in front of entrance window. Flexure is 0.95 pixels peak to peak at the detector or 51.16 mm at telescope focus pointing opposite to direction of gravity.

FIGURE 42. Internal flexure of Sofi objective SF and focal elongator measured at 24 positions. Inner curve shows movement of point image on detector for one full revolution. Position of closed cycle cooler indicated on rotated squares as seen standing in front of entrance window. Flexure is 4.26 pixels peak to peak at the detector or 57.25 mm at telescope focus pointing normal to direction of gravity.

FIGURE 43. Flexure of Sofi objective SF with focal elongator measured at 24 positions.Inner circle shows movement of point image on detector for one full revolution. Position of closed cycle cooler indicated on rotated squares as seen standing in front of entrance window. Flexure is 35.64 pixels peak to peak at the detector or 479.03 mm at telescope focus pointing in direction of gravity.

FIGURE 44. Internal flexure of Sofi objective SF and focal elongator measured at 28 positions. Inner curve shows movement of point image on detector for one full revolution. Position of closed cycle cooler indicated on rotated squares as seen standing in front of entrance window. Flexure is 0.84 pixels peak to peak at the detector or 11.29 mm at telescope.

FIGURE 45. Internal flexure of Sofi objective SF measured at 28 positions. Inner curve shows movement of point image on detector for one full revolution. Position of closed cycle cooler indicated on rotated squares as seen standing in front of entrance window. Flexure is 1.14 pixels peak to peak at the detector or 30.64 mm at telescope focus.

FIGURE 46. Persistence as function of temperature.

FIGURE 47. Flexure of Sofi objective LF measured at 24 positions.Inner circle shows movement of point image on detector for one full revolution. Position of closed cycle cooler indicated on rotated squares as seen standing in front of entrance window. Flexure is 4.0 pixels peak to peak at the detector or 215.43 mm at telescope focus pointing in direction of gravity.

FIGURE 48. Flexure of Sofi objective SF with focal elongator measured at 24 positions.Inner circle shows movement of point image on detector for one full revolution. Position of closed cycle cooler indicated on rotated squares as seen standing in front of entrance window. Flexure is 12.3 pixels peak to peak at the detector or 165.32 mm at telescope focus pointing in direction of gravity.

FIGURE 49. Internal flexure of Sofi objective LF measured at 24 positions. Inner curve shows movement of point image on detector for one full revolution. Position of closed cycle cooler indicated on rotated squares as seen standing in front of entrance window. Flexure is 1.2 pixels peak to peak at the detector or 64.63 mm at telescope focus.

FIGURE 50. .Comparison of flexure with and without counterbalancing weight and soft suspension to cold structure as observed with objective SF and focal elongator. The downward shift vectors are measured without counterweights the upward vectors with a counterweight of 15 kp.

FIGURE 51. Pixel transfer function determined with shot noise method. For a gain of 3 of the warm preamplifier the gain is 1.94 +/- 0.07 electrons/ADU.

FIGURE 52. Pixel transfer function determined with shot noise method. For a gain of 1 of the warm preamplifier the gain is 5.58 +/- 0.2 electrons/ADU.

FIGURE 53. Efficiency of Instrument excluding filter but including detector for small field objective and focal elongator. Efficiency is 0.402 +/- 0.001. Total efficiency including narrow band 2.28 mm filter is 0.277.

FIGURE 54. Efficiency of Instrument excluding filter but including detector for small field objective. Efficiency is 0.545 +/- 0.002. Total efficiency including narrow band 2.28 mm filter is 0.376.

FIGURE 55. Efficiency of Instrument excluding filter but including detector for large field objective. Efficiency is 0.524 +/- 0.003. Total efficiency including narrow band 2.28 mm filter is 0.362.

FIGURE 56. Total efficiency of red grism with longpass filter in SOFI including optical loss of all components and quantum efficiency of detector. Difference of 2 spectra with blackbody at temperatures 30 C and 60 C and slit of 2 arcseconds were used.

FIGURE 57. Total efficiency of SOFI with narrow band filters in spectroscopy mode including optical loss of all components and quantum efficiency of detector. Upper curve is efficiency with red grism and longpass filter. Difference of 2 spectra with blackbody at temperatures 30 C and 60 C and slit of 2 arcseconds were used.

FIGURE 58. Optical quality of objective LF at 11x11 positions within the field expressed in terms of full width half maximum. FWHM is 1.3 +/- 0.14 pixels.

FIGURE 59. Optical quality of objective LF at 11x11 positions within the field expressed in terms of Strehl ratio. Strehl ratio is 0.34 +/- 0.07.

FIGURE 60. Image of point source taken with objective LF at center of the array.

FIGURE 61. Image of point source taken with objective LF in upper left corner of the array. Image is elongated (6 pixels at 1% of maximum signal)

SOFI TESTS

Gert Finger