Convert Arcseconds to Semicircles

Convert Arcseconds (″) to Semicircles (sc) instantly and accurately.

Conversion Formula

sc = ″ × 1.543209877e-6

About Arcseconds

An arcsecond (″) is 1/3,600 of a degree - π/648,000 rad ≈ 4.848 × 10⁻⁶ rad. It is the fundamental resolution unit of classical astronomy and geodetic surveying. The Hubble Space Telescope delivers ~0.05″ resolution; atmospheric seeing at excellent sites gives 0.4-0.6″. Stellar parallax of Proxima Centauri is 0.7687″, defining its distance of 1.3009 parsecs. The parsec is defined as the distance at which 1 AU subtends exactly 1 arcsecond - giving 1 pc = 3.0857 × 10¹⁶ m. 1″ = π/648,000 rad ≈ 4.848 µrad.

About Semicircles

A semicircle equals 1/2 of a full circle - exactly π rad = 180°. GPS and GLONASS transmit satellite orbital elements with latitude and longitude in semicircles, maximising angular resolution within 32-bit signed integers: ±2³¹ units span ±π rad with ~1.46 × 10⁻⁹ rad resolution per unit. Euler's identity e^(iπ) + 1 = 0 encodes exactly 1 semicircle of rotation in the complex plane, mapping 1 to -1 - often called the most beautiful equation in mathematics. 1 semicircle = π rad = 180° = 200 grad = 3,200 NATO mils.

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