
Flash Guide Number Calculator
Find ideal flash aperture or subject distance from a supplied ISO-100 guide number.
Open toolFind the ideal circular-aperture Rayleigh angular resolution. Provide Wavelength (m), Circular aperture diameter (m) to compute results directly in your browser. Theta=1.22*wavelength/diameter in radians using small-angle far-field diffraction. Arcseconds also shown; no atmospheric seeing, sensor sampling or real-equipment performance guarantee. Inputs and results use floating-point numbers; output shows up to 12 significant digits. Rounding can occur.
Enter the inputs, then select Calculate.
Result will appear here
The Rayleigh Criterion Calculator evaluates Wavelength (m), Circular aperture diameter (m) in client-side JavaScript using the deterministic rule below and updates the output panel immediately without uploading data to a server.
Find the ideal circular-aperture Rayleigh angular resolution.
Theta=1.22*wavelength/diameter in radians using small-angle far-field diffraction. Arcseconds also shown; no atmospheric seeing, sensor sampling or real-equipment performance guarantee. Inputs and results use floating-point numbers; output shows up to 12 significant digits. Rounding can occur.
Review the input parameters, allowed value ranges, and worked reference cases for the Rayleigh Criterion Calculator below before running your calculation.
| Parameter / Scenario | Default / Sample Value | Rule or Allowed Range | Output / Usage Note |
|---|---|---|---|
| Input: Wavelength (m) | 5e-07 | Range: 1e-30 to 1000000000.0 | Required workspace parameter |
| Input: Circular aperture diameter (m) | 0.1 | Range: 1e-09 to 1000000000.0 | Required workspace parameter |
| Worked Case 1: Baseline run (Wavelength (m) = 5e-07) | Preloaded / test values | Find the ideal circular-aperture Rayleigh angular resolution | Wavelength (m) = 5e-07; Circular aperture diameter (m) = 0.1. The displayed output is Radians: 0.0000061 Arcseconds: 1.25821531811. |
| Worked Case 2: Comparison scenario (rayleigh criterion formula) | Preloaded / test values | Find the ideal circular-aperture Rayleigh angular resolution | Wavelength (m) = 6e-7; Circular aperture diameter (m) = 0.2. The displayed output is Radians: 0.00000366 Arcseconds: 0.754929190864. |
Follow these three steps to configure Wavelength (m), Circular aperture diameter (m), verify unit and boundary rules, and export your Rayleigh Criterion Calculator output.
Set circular aperture diameter (m). Use wavelength and circular-aperture diameter under the stated small-angle diffraction approximation.
Select Calculate to see the ideal resolution angle in radians and arcseconds. Copy result copies this text; Download saves it as a TXT file.
These concrete scenarios illustrate how the Rayleigh Criterion Calculator processes baseline inputs, comparison checks, and boundary constraints.
Wavelength (m) = 5e-07; Circular aperture diameter (m) = 0.1. The displayed output is Radians: 0.0000061 Arcseconds: 1.25821531811.

Wavelength (m) = 6e-7; Circular aperture diameter (m) = 0.2. The displayed output is Radians: 0.00000366 Arcseconds: 0.754929190864.

When solving for 'rayleigh criterion calculator', verify that Wavelength (m), Circular aperture diameter (m) use consistent units and stay within the documented scope: Theta=1.22*wavelength/diameter in radians using small-angle far-field diffraction. Arcseconds also shown; no atmospheric seeing, sensor sampling or real-equipment performance guarantee. Inputs and results use floating-point numbers; output shows up to 12 significant digits. Rounding can occur.

The output panel reports the exact result derived from Wavelength (m), Circular aperture diameter (m) alongside any unit or formatting notes.
The result is the ideal resolution angle in radians and arcseconds. Estimate a circular aperture's Rayleigh diffraction angle.
This ideal diffraction limit does not include seeing, sensor sampling or a real instrument's measured performance.
Numerical output shows up to 12 significant digits. Floating-point arithmetic and display rounding can affect the last digits.

Review these boundary constraints and validation rules before relying on the Rayleigh Criterion Calculator output.
Operational scope: Theta=1.22*wavelength/diameter in radians using small-angle far-field diffraction. Arcseconds also shown; no atmospheric seeing, sensor sampling or real-equipment performance guarantee. Inputs and results use floating-point numbers; output shows up to 12 significant digits. Rounding can occur. Inputs that violate minimum/maximum bounds or required format rules are rejected with a clear diagnostic prompt.
Need an adjacent calculation in Everyday Math? Use the related tools linked below to chain your workflow without leaving your browser.


Find ideal flash aperture or subject distance from a supplied ISO-100 guide number.
Open tool
Find stable angular separation between supplied celestial or spherical coordinates.
Open tool
Find ideal bicycle pedal cadence or speed using wheel circumference and gear ratio.
Open toolChoose another tool for your next calculation, conversion, or text task.

Find the time constant of an ideal first-order RC circuit as RC.
Open tool
Scale each supplied ingredient amount by the target-to-original serving ratio.
Open tool
Find ideal boiling-point elevation as i times Kb times molality.
Open tool
Find ideal capacitive reactance magnitude as 1/(2πfC).
Open toolAnswers about using Rayleigh Criterion Calculator and understanding its results.
The Rayleigh Criterion Calculator applies the rule: Find the ideal circular-aperture Rayleigh angular resolution. Enter Wavelength (m), Circular aperture diameter (m) into the workspace and the tool computes the exact output in your browser.
Yes. Provide Wavelength (m), Circular aperture diameter (m) using the documented units and format shown in the quick reference table above. Preloaded default values let you test the workflow immediately.
Theta=1.22*wavelength/diameter in radians using small-angle far-field diffraction. Arcseconds also shown; no atmospheric seeing, sensor sampling or real-equipment performance guarantee. Inputs and results use floating-point numbers; output shows up to 12 significant digits. Rounding can occur. Confirm that your inputs fall within the allowed ranges before exporting the result.
Yes. All calculations for the Rayleigh Criterion Calculator execute 100% locally in your browser's JavaScript runtime. No inputs or results are uploaded to any external server.
Choose another tool for your next calculation, conversion, or text task.