跟踪误差容限计算器 — 公式
## 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.
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.
计算示例
0.77 arcsec/px scale, 2 px acceptable drift, 480 s worm period.
- PE_max = 0.77 * 2 = 1.54 arcsec
- Drift rate = 1.54 / 480 * 60 = 0.1925 arcsec/min