Convert Signs to Arcminutes
Convert Signs (sign) to Arcminutes (′) instantly and accurately.
Conversion Formula
′ = sign × 1800
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.
About Arcminutes
An arcminute (′) is 1/60 of a degree - π/10,800 rad ≈ 2.909 × 10⁻⁴ rad. One arcminute of latitude equals exactly one nautical mile (1,852 m), which is the origin of the nautical mile unit. The Moon and Sun both subtend ~30 arcminutes in apparent diameter - the coincidence exploited in total solar eclipses. Human 20/20 visual acuity resolves letters 5 arcminutes tall at 6 m. Binocular and telescope apparent fields of view are quoted in arcminutes. 1′ = π/10,800 rad ≈ 0.01667° ≈ 290.9 µrad.
Quick Reference Table
| Signs (sign) | Arcminutes (′) |
|---|---|
| 1 sign | 1800 ′ |
| 2 sign | 3600 ′ |
| 5 sign | 9000 ′ |
| 10 sign | 18000 ′ |
| 25 sign | 45000 ′ |
| 50 sign | 90000 ′ |
| 100 sign | 180000 ′ |