ATRONOMY – TELECOPE & OPTIC (46) CALCULATOR
Tracking Error
A precise tool.
What is the Tracking Error & How does it work?
Tracking error is the angular deviation of a telescope’s pointing from the ideal sidereal track during an exposure. It arises because most mounts cannot perfectly follow the Earth’s rotation, and the residual motion accumulates over time.
The magnitude of the error depends on two main factors: the length of the exposure and the target’s declination. At higher declinations the sky rotates more slowly in hour‑angle, reducing the apparent drift, while longer exposures give the error more time to grow.
By estimating tracking error you can decide whether an exposure will be acceptably sharp or if you need guiding or a shorter integration. The simple model below assumes a constant periodic error and uses the cosine of the declination to scale the drift.
\text{TE}=t_{exp}\times15\times\cos\left(\delta\right)
t_{exp} = exposure time (seconds)
\delta = declination (degrees)
\delta = declination (degrees)
Parameters
Result
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Frequently Asked Questions
What is tracking error in astronomy?
Tracking error is the angular deviation of a telescope’s pointing from the ideal sidereal track during an exposure, caused by the mount not perfectly following Earth’s rotation.
How does declination affect tracking error?
At higher declinations, the sky rotates more slowly in hour-angle, reducing the apparent drift and thus minimizing tracking error.
What factors determine the magnitude of tracking error?
The magnitude of tracking error depends on two main factors: the length of the exposure and the target’s declination.
Can longer exposures increase tracking error?
Yes, longer exposures give the tracking error more time to accumulate, potentially increasing its magnitude.
How can I minimize tracking error in my observations?
To minimize tracking error, use a mount with high accuracy, choose shorter exposure times when possible, and aim for targets at higher declinations where the sky rotates more slowly.
Is there a formula to calculate tracking error?
While specific formulas can vary, generally, tracking error is calculated by considering the mount’s accuracy, exposure time, and the target’s declination.
What are the consequences of significant tracking error in astronomical observations?
Significant tracking error can lead to blurred images or loss of detail in astronomical observations, affecting the quality of the data collected.
Results are for informational purposes only and do not constitute professional advice.