Intensified cameras
Instrument P.I.: Peter Jenniskens, SETI Institute.
The information below will be updated as more precise data is received.
Technique: Wide field intensified cameras. Example video from the 2001 Leonid MAC mission (no grating).
Scientific objective: To measure the total radiative output of the SRC during entry in the 400 - 900 nm band.
Instrument: Four cameras, two on both sides of the aircraft, consist of a 50 mm f2.8 Nikon lens, an XX1332 image intensifier with large 48 mm photocathode, and a Sony handycam camcorder (recording of video output on Hi-8 tape in NTSC format - 640 x 480 pixels). The lens can be equipped with a low-dispersion grating to generate 1st and higher order spectra, each containing a fraction of the light. This facilitates the measurement of luminosity when the zero order image saturates.
Heritage: These cameras were flown before to record meteors. The figure to the right shows the setup during the 2002 Leonid MAC mission, when an ESA camera was mounted on top. In this mission "PHOT" will be mounted on top of the INT1 camera.
Aircraft hardware requirements: Fixed mount. Electricity at window. Optional: operation on batteries.
Instrument validation tests: These cameras were flown before for near-real time flux measurements of meteor storms. The response of the low-dispersion grating to continuum sources was tested in laboratory conditions.
Sensitivity: With a 40 x 30 degree field of view, the star limiting magnitude is about +6.5 magnitude (with Moonlight).
Dynamic range: 8-bit (factor 256).
Frame rate and exposure times: 30 frames per second, 60 fields (odd, even, interlaced) per second. Exposure time is nearly 1/60s per field.
Spectral resolution - gives the FWHM of an instrument-broadened unresolved atomic spectral line:
Very low, about 25 nm.
Relative spectral response - gives the wavelength dependence of the intensifier. The Quantum Efficiency of the system depends somewhat on the angle of viewing through the window (near-UV cut-off) and the choice of objective grating:
wavelength: Radiant sensitivity:
(nm) (micro A/lm)
380 5.000
390 6.000
400 7.200
410 8.500
420 11.000
430 14.000
440 19.500
450 21.798
460 23.878
470 25.771
480 27.492
490 29.051
500 30.462
510 31.736
520 32.883
530 33.912
540 34.832
550 35.650
560 36.374
570 37.010
580 37.563
590 38.037
600 38.436
610 38.763
620 39.019
630 39.207
640 39.325
650 39.375
660 39.353
670 39.258
680 39.088
690 38.837
700 38.502
710 38.077
720 37.555
730 36.929
740 36.192
750 35.334
760 34.346
770 33.217
780 31.936
790 30.491
800 28.868
810 27.054
820 25.034
830 22.792
840 20.313
850 17.579
860 14.520
870 10.000
880 5.500
890 4.000
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