My telescope spec lists a 0.5-degree field of view. How many arcseconds wide is that?

0.5 × 3,600 = 1,800 arcseconds. The full Moon's disc (about 1,800 arcseconds diameter) would just fit in view — a quick sanity check for lunar photography planning.

A star catalog lists a star at 12°34′56″. How many total arcseconds from the reference point?

12° = 43,200″ + 34′ = 2,040″ + 56″ = 45,296 arcseconds total. Or: 12.5822° × 3,600 = 45,296 arcseconds.

Why do astronomers use arcseconds instead of decimal degrees?

At the scales astronomers work, differences of 0.001° are meaningful — but writing '0.001°' is less intuitive than '3.6 arcseconds'. Arcseconds keep numbers in a human-readable range for small angular separations.

My GPS has a horizontal accuracy of 3 meters. What's that in arcseconds of latitude?

1 arcsecond of latitude ≈ 30.9 m at the equator. So 3 m ÷ 30.9 ≈ 0.097 arcseconds — your GPS is accurate to about 0.1 arcseconds of position.

Degrees to Arcseconds Converter

Enter a value to instantly convert between angle units.

From

Precision4 dp

1 Degree = 3600 Arcsecond

Key Formulas

Degree → Radian

rad = ° × 0.0174533

Radian → Degree

° = rad × 57.2958

Degree → Gradian

grad = ° × 1.11111

Gradian → Degree

° = grad × 0.9

Formula

arcseconds = degrees × 3600

Astronomers express the separation between stars, the angular diameter of celestial objects, and telescope resolution limits all in arcseconds. The Hubble Space Telescope resolves features down to about 0.05 arcseconds; a backyard telescope might manage 1–2 arcseconds. Precision surveyors use arcseconds for geodetic work where millimetre-level position accuracy across kilometres matters. Converting from the degrees of a star atlas or site survey plan to arcseconds is standard practice in these fields.

Source: ISO 80000-3:2019 (Quantities and units — Space and time)

Last reviewed: 2026-06-11 · see our methodology

Frequently Asked Questions

Real-World Examples

One arcsecond — the angular resolution limit of a perfect 115 mm aperture telescope, and the seeing limit of a good night at a dark-sky observatory.

0.000278 ° = 1 ″

One degree of sky — 3,600 arcseconds, roughly 7 times the angular diameter of the full Moon (0.5° = 1,800 arcseconds).

1 ° = 3600 ″

Angular diameter of Jupiter at opposition — about 50 arcseconds (≈ 0.014°), the largest planetary disc visible from Earth besides the Moon.

0.0028 ° = 10.1 ″

Gravitational deflection of starlight near the Sun — 1.75 arcseconds, the famous measurement from the 1919 eclipse that confirmed general relativity, expressed as a tiny fraction of a degree.

2.3e-10 ° = 0.00083 ″

degrees to radians radians to degrees degrees to gradians gradians to degrees

Degrees to Arcseconds Converter

Key Formulas

Formula

Frequently Asked Questions

Real-World Examples

Related Converters