Star Trail Length Pixels Per Minute
SiderealrotationtrailRATEpixels/minute atactualdeclinationfixednontrackingdetectorlocaltangentplane,not generic observedmoving-sourcemotion. Actual independent model/unit/frame/epoch/calibration and applicable measurement established;not precise ephemeris,forecast,geodesy operation,identity or safety approval.
Description
A stationary camera records star motion caused by Earth’s sidereal rotation.
A stationary camera records star motion caused by Earth’s sidereal rotation.1
This calculator converts the local angular trail rate at a supplied declination into pixels per minute using the detector’s independently established angular scale.
When to use Star Trail Length Pixels Per Minute
Use this tool to apply the stated star trail length pixels per minute operation with an explicit input and unit basis.
How to use Star Trail Length Pixels Per Minute and how it works
- Establish the measurement basis and units described above.
- Enter actualDeclinationDegrees, callerActualDetectorArcsecondsPerPixel and run the tool.
- Read result.value using the output meanings below.
- If input is rejected, correct the stated type, range, ordering or alignment issue and rerun; review successful results under the declared convention.
| Input field | Meaning | Value type | Requirement |
|---|---|---|---|
| actualDeclinationDegrees | Declination Degrees. Units, ordering and applicable branch are specified in the algorithm. | number | required; finite; further conditions in the algorithm |
| callerActualDetectorArcsecondsPerPixel | Detector Arcseconds Per Pixel. Units, ordering and applicable branch are specified in the algorithm. | number | required; finite; strictly positive; further conditions in the algorithm |
Require declination within −90–90 degrees and positive arcseconds per pixel. Use a sidereal day of 86164.0905 seconds, multiply the equatorial rate by abs(cos(declination)) and divide by the pixel scale; tracking, distortion and a wide-field projection are outside this local approximation.
pixels/min = (360/86164.0905) × 3600 × 60 × abs(cosδ)/arcsecondsPerPixel Apply the declared units, ordering and branch conditions.
| Output field | Meaning | Value type |
|---|---|---|
| result | Object containing the declared output fields. | object |
| result.value | Local stationary-camera trail rate in pixels per minute. | number |
{
"input": {
"actualDeclinationDegrees": 0,
"callerActualDetectorArcsecondsPerPixel": 1
},
"output": {
"result": {
"value": 902.4641187386524
}
}
}Limitations and assumptions
The output applies the declared operation to the values you supply. Establish the measurement basis, units, coefficients and any caller-selected rules before interpreting it. The tool does not independently collect or verify observations or decide whether a model or reference applies.
Supply explicit required fields with the documented types and dense aligned arrays. Unknown fields, wrong types and nonfinite numbers are rejected. Branch-specific constraints are explained above. A returned boolean, signed difference or tied result follows the stated convention; an input error instead means the required input contract was not satisfied. Very large inputs or outputs may be rejected by shared resource limits.
Alternative or Complementary methods
For a related operation, use Small Angle Formula Arcseconds Calculator. The small-angle formula relates a transverse physical size to an angular size when the size-to-distance ratio is small.
For a related operation, use Angular Size From Diameter and Distance. A planar disk’s angular diameter follows exact tangent geometry at its center distance.
References
-
Star Trail Length Pixels Per Minute — tool.io
Similar or alternative tools
- Small Angle Formula Arcseconds Calculator
The small-angle formula relates a transverse physical size to an angular size when the size-to-distance ratio is small.
- Angular Size From Diameter and Distance
A planar disk’s angular diameter follows exact tangent geometry at its center distance.