Convert Microradians to Signs
Convert Microradians (µrad) to Signs (sign) instantly and accurately.
Conversion Formula
sign = µrad × 1.909859317e-6
About Microradians
A microradian (µrad) is one millionth of a radian (10⁻⁶ rad ≈ 0.206265 arcseconds). It is the standard unit for small angles in precision optics and structural monitoring. A 1 µm wavelength beam from a 1 mm aperture has a diffraction-limited half-angle divergence of ~1 µrad. Atmospheric seeing for ground-based telescopes is typically 2.4-9.7 µrad (0.5-2 arcseconds). Autocollimators resolve angular deviations to 0.05-1 µrad for machine tool alignment. Building tilt monitoring tracks µrad/day. 1 µrad ≈ 0.2063″ = 0.2063 arcseconds.
About Signs
An astrological sign equals 1/12 of a full circle - π/6 rad = exactly 30°. The zodiac divides the ecliptic into twelve 30° signs (Aries through Pisces), originating in Babylonian astronomy ~5th century BCE. Historical ecliptic longitude was expressed as sign + degrees: "Scorpio 12°" = 222°. The 30° spacing also appears in music theory: the circle of fifths has twelve equally spaced positions 30° apart, and the octave divides into 12 equal semitones. 1 sign = 30° = 1,800′ = π/6 rad = 533.3 NATO mils.
Quick Reference Table
| Microradians (µrad) | Signs (sign) |
|---|---|
| 1 µrad | 1.91 × 10-6 sign |
| 2 µrad | 3.82 × 10-6 sign |
| 5 µrad | 9.549 × 10-6 sign |
| 10 µrad | 1.91 × 10-5 sign |
| 25 µrad | 4.775 × 10-5 sign |
| 50 µrad | 9.549 × 10-5 sign |
| 100 µrad | 0.000190986 sign |