Centroiding Notes

Factors contributing errors

  1. Lens distortion
  2. Lens abberations (chromatic abberation, coma, astigmatisms, etc.)
  3. Variation in illumination (intensity variation in light source)
  4. Background noise in CCD camera
  5. Photonic noise (inherent randomness)
  6. Vibration

Techniques to improve accurary

  1. Calibrate background (tradeoff: small reduction in S/N)
  2. Distortion model
  3. Frame averaging (improves S/N, smooths variation in illumination & photonic noise)
  4. Cross-correlation (non-linear least-squares fit of multiple point sources on bug)
  5. Air bench (not plausible on telescope though)

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