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Table 1
Basic parameters of the NAC and WAC system and CCD specification (Keller et al. 2007).
| NAC | WAC | |
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| Optical design | 3-mirror off-axis | 2-mirror off-axis |
| Detector type | 2k × 2k CCD | 2k × 2k CCD |
| Angular resolution (μrad px-1) | 18.6 | 101 |
| Focal length (mm) | 717.4 | 140 (sag)/131 (tan) |
| Field of view (°) | 2.20 × 2.22 | 11.35 × 12.11 |
| Telescope aperture | 6.49 × 10-3 m2 | 4.91 × 10-4 m2 |
| F-number | 8 | 5.6 |
| Spatial scale from 1km (cm px-1) | 1.86 | 10.1 |
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| NAC and WAC CCD | ||
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| Pixel size | 13.5 × 13.5μm2 | |
| Full well | >120 000 e− px-1 | |
| System gain | ≈3.1 e−/DU | |
| Readout noise (CCD) | ≈15 e− rms | |
| Dark charge generation | <0.1 e− s-1 px-1 @180 K | |
| ≈400 e− s-1 px-1 @293 K – (with dithering) | ||
| Readout rate | 1.3 Mpx s-1; 650 kpx s-1 per channel | |
| Readout time (full frame) | 3.4 s (2 channels) | |
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