## System Description

Telescope | Meade LX200 12" |

Sub aperture layout | Two pairs diagonal |

Sub aperture d | 7.4 cm |

Sub aperture separation D | 20.5 cm |

Detector | WATEC WAT-100N |

Pixel scale | 0."667 (Horizontal) x 0."627 (Vertical)/pixel |

Exposure time | 0.5, 0.2, 0.1ms adjusted to observing condition |

CCD gain | 50 dB fixed |

Wavelength | 0.5 um |

Wavelength range | 0.3-1.1 um |

Realtime data aquisition | Linux based PC |

Sampling rate | 30 frames / second |

Seeing values are calculated from image motions by the following procedures.
An image motion is defined to be a variance of image centroids.
The centroids are obtained in every captured frame and accumulated up to 60 data points to calculate the variance σ
σ
Also the relation between r
σ
Here, λ is wavelength, D is a diameter of sub apertures and d is a distance between sub apertures.
In case of our system, 0.5um for λ, 7.4cm for D and 20.5cm for d are adopted. FWHM θ is estimated numerically with λ and r
θ = 0.98 x λ/r Finally, the zenith distance correction is applied,
θ(0) = θ(z) x cos(z) where z is a zenith distance, θ(z) is the observed seeing and θ(0) is the seeing at zenith. |