Collection half-angle to numerical aperture
Type a value in ° to get it in NA instantly.
0.01134NA
Nothing on our list is smaller: a scanning objective is 8.8× sharper. It can separate detail down to about 24,240 nm.
Convert the other way: NA to °
What it means
How fine can it see?
Resolution figures use green light at 550 nm and the Abbe limit. Shorter wavelengths resolve finer, which is why electron microscopes exist.
The math
How to convert ° to NA
Resolution and aperture are reciprocals through the wavelength: resolution = λ ÷ 2NA, which at 550 nm is 275 ÷ NA nanometers. The collection angle is arcsin(NA).
Example: 0.65 ° = 0.0113444 NA.
Every unit
Your aperture in every unit
Tables
° to NA conversion table
| ° | NA |
|---|---|
| 2.29 ° | 0.0399574 NA |
| 5.74 ° | 0.100014 NA |
| 14.5 ° | 0.25038 NA |
| 23.6 ° | 0.400349 NA |
| 40.5 ° | 0.649448 NA |
| 48.6 ° | 0.750111 NA |
| 58.2 ° | 0.849893 NA |
| 71.8 ° | 0.949972 NA |
NA to ° conversion table
| NA | ° |
|---|---|
| 0.04 NA | 2.29244 ° |
| 0.1 NA | 5.73917 ° |
| 0.25 NA | 14.4775 ° |
| 0.4 NA | 23.5782 ° |
| 0.65 NA | 40.5416 ° |
| 0.75 NA | 48.5904 ° |
| 0.85 NA | 58.2117 ° |
| 0.95 NA | 71.8051 ° |
Quick answers
Quick answers
- How many NA is 1 °?
- 1 ° is 0.0174524 NA.
- How many NA is 10 °?
- 10 ° is 0.173648 NA.
- How many NA is 0.65 °?
- 0.65 ° is 0.0113444 NA.
The units
About these units
Collection half-angle (°)
The half-angle of the light cone it gathers, in air.
Numerical aperture (NA)
The sine of the collection half-angle, times the refractive index.
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