Telescope: |

**Mounting of telescope:** | altitude-azimuth |

**Total moving weight of telescope:** | 43 tons |

**Weight of telescope tube:** | 6800 kg |

**Type of optical system:** | (Super) Ritchey-Chretien |

**Equivalent focal distance of system:** | 28160 mm |

**Effective aperture ratio of system:** | f/11 |

Position: |

**Longitude:** | 17° 52' 59.7" W = 1h 11m 32.0s W |

**Longitude (new from GPS):** | 17° 53' 06.3" W |

**Latitude:** | +28° 45' 20.5" |

**Latitude (new from GPS):** | +28° 45' 26.2" |

**Altitude:** | 2382 m |

**Minimum accessible declination:** | -55 deg. |

Primary mirror (M1): |

**Second degree coefficient of radius:** | -4.8828125 x 10^-5 |

**Fourth degree coefficient of radius:** | +1.721171778 x 10^-15 |

**Sixth degree coefficient of radius:** | -1.5207 x 10^-25 |

**Mirror material:** | Zerodur, delivered by Schott Glaswerke in Mainz, Germany |

**Mirror:** | Ground and polished at Tuorla Observatory, university of Turku, early spring 1988 |

**Diameter:** | 2560 mm |

**Diameter of aperture stop:** | 2495 mm |

**Diameter of central hole:** | 340mm |

**Peripheral thickness:** | 190.3mm |

**Weight:** | 1925 kg |

**Focal Length:** | 5120 mm |

**Aperture ratio:** | f/2 |

**Conic constant:** | -1.014785 |

Secondary mirror (M2): |

**Diameter:** | 510 mm |

**Weight:** | 35 kg |

**Radius of curvature:** | -2287.25 mm |

**Conic constant:** | -2.234127 |

Other: |

**Min zenith distance due to zenith sigularity:** | 4 arcmin |

**Blind tracking accuracy:** | 0.17 "/min at zenith distance 14° 0.6 "/min at zenith distance 70° |

**Linear coefficient of thermal expansion of mirrors:** | <0.00000001/K (between 0° and 50°C) |

**Energy concentration:** | 80% within 0.4" 100% within 0.7" |

**Total field of view:** | 30' |

**Focal plane scale:** | 7.33"/mm |

**Focus-value scale (in telescope focal plane):** | 66 focus units / mm shift ( or 15.2 micron/unit) |

**Focus-value scale (at secondary):** | 0.35 micron movement per focus unit (a positive offset moves the secondary away from the primary) |

**Autoguider X,Y probe scale:** | 0.00718 arcsec per unit |

**Autoguider TV pixel scale:** | 0.222 arcsec in X and 0.145 arcsec in Y |