Autocollimator Angle
Convert autocollimator spot displacement into mirror angle.
Description
An autocollimator detects mirror rotation through doubled reflected-ray deflection.
An autocollimator detects mirror rotation through doubled reflected-ray deflection. Small-angle spot displacement is divided by twice focal length.1
Convert autocollimator spot displacement into mirror angle.
When to use Autocollimator Angle
Use this tool to convert autocollimator spot displacement into mirror angle.
Prepare the optical measurements, geometry, fitted coefficients or caller-selected thresholds requested. Confirm wavelength, radius/diameter, pulse-width, angle and unit conventions before running the calculation.
How to use Autocollimator Angle and understand its results
- Prepare the optical measurements, geometry, fitted coefficients or caller-selected thresholds requested. Confirm wavelength, radius/diameter, pulse-width, angle and unit conventions before running the calculation.
- Enter spotDisplacementMillimeters, autocollimatorFocalLengthMillimeters using the field table and calculation rules, then run the tool.
- Read mirrorAngleRadians, mirrorAngleArcseconds. The explanation below defines the units, signs, ordering and any flags or placeholder values.
- If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.
| Input field | Meaning | Value type; see rules below | Requirement |
|---|---|---|---|
| spotDisplacementMillimeters | Reflected spot displacement (mm) | number | Required |
| autocollimatorFocalLengthMillimeters | Autocollimator focal length (mm) | number; minimum: 0 | Required |
Enter finite signed displacement and positive focal length in mm. Return radians and arcseconds.
angleRadians=displacement/(2focalLength) Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| mirrorAngleRadians | Mirror angle (rad) | number |
| mirrorAngleArcseconds | Mirror angle (arcsec) | number |
{
"input": {
"spotDisplacementMillimeters": 2,
"autocollimatorFocalLengthMillimeters": 1
},
"output": {
"mirrorAngleRadians": 1,
"mirrorAngleArcseconds": 206264.80624709636
}
}Limitations and assumptions
No exact arctangent, optical calibration, alignment or uncertainty is calculated.
Numeric inputs must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.
Alternative or Complementary methods
Use Brewster Angle: Calculate Brewster angle between two supplied refractive indices. For a complementary task, use Rotary-Axis Calibration: Summarize rotary-axis calibration errors in arcseconds.
References
-
Autocollimator Angle — tool.io
Similar or alternative tools
- Brewster Angle
Calculate Brewster angle between two supplied refractive indices.
- Rotary-Axis Calibration
Summarize rotary-axis calibration errors in arcseconds.