Calculateur de Tolérance d'Erreur de Suivi — Formule

Tracking Error Tolerance

For unguided astrophotography, the mount's periodic error (PE) must be small enough that stars do not trail beyond the pixel scale.

Formula

PE_max = pixel_scale * drift_pixels

  • *pixel_scale* = arcsec/pixel from sensor and focal length
  • *drift_pixels* = acceptable pixel drift (typically 1 to 2 px)

    • The drift rate limit is PE_max divided by the worm-gear period.

    Exemple Résolu

    0.77 arcsec/px scale, 2 px acceptable drift, 480 s worm period.

    1. PE_max = 0.77 * 2 = 1.54 arcsec
    2. Drift rate = 1.54 / 480 * 60 = 0.1925 arcsec/min