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Table 4.
Metis optical parameters.
| Telescope type | Externally occulted, on-axis aplanatic Gregorian |
| Overall length | 1309 mm |
| Effective focal length | VL: 200 mm |
| UV: 300 mm | |
| Inverted External Occulter (IEO) | Circular aperture: 40.0 mm |
| Distance IEO-M0 (boom): 800.0 mm | |
| Sun-light rejection mirror (M0) | Spherical: 71.0 mm |
| Curvature radius: 1600.0 mm | |
| Primary mirror (M1) | On axis ellipsoidal: outer 160.0 mm, inner 88.0 mm |
| Curvature radius: 272.00 mm | |
| Conic: −0.662 | |
| Secondary mirror (M2) | On axis ellipsoidal: outer 216.0 mm, inner 125.0 mm |
| Curvature radius: 312.4 mm | |
| Conic: −0.216 | |
| Internal occulter (IO) | Distance M1-IO: 154.8 mm |
| Circular: 5.0 mm | |
| Wavelength band-passes | VL: 580–640 nm |
| UV: H I Lyman-α (121.6 ± 10) nm | |
| Detectors | VL: APS |
| – Scale factor 10.7 arcsec pixel−1 | |
| – Image size: 20.7 mm (2048 × 2048) with 10 μm pixel size | |
| UV: Intensified-APS | |
| – Scale factor 20 arcsec/equivalent pixel | |
| – Image size: 30.7 mm (1024 × 1024) with 30 μm equivalent pixel size at the UV focal plane (microchannel plate), downsized by a factor 2 by a tapered fibre optics to match the sensor 15 μm pixel size |
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