21 Arc Seconds to Degrees

21" ≈ 0.0058333°

Calculation: ° = 21" × 0.000277778 ≈ 0.0058333°

Arc Second to Degree Converter

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Sig. Figures:

How wide is 21"?

21 arc second (0.006 degrees) is comparable to the precision of a telescope crosshair, an almost imperceptible angle.

What does 21" look like?

Illustration of a telescope crosshair reticle
21 arc second (0.006 degrees) is comparable to the precision of a telescope crosshair, an almost imperceptible angle.

How to Convert Arc Second to Degree

1 arc second = 0.000277778 degrees

Degree = Arc Second × 0.000277778

Example: 21" × 0.000277778 = 0.0058333°

Reverse Conversion

To convert degrees back to arc seconds:

  • Remember, 1 degree equals 3600 arc seconds.
  • To convert 0.0058333° to", multiply 0.0058333 x 3600, resulting in 21".

21 " is also equal to:

  • 0.00010181 radian
  • 0.0064815 gradian

Frequently Asked Questions

How much is 21 arc seconds in degrees?

21 arc seconds equals 0.0058333 degrees. This is calculated by multiplying 21 by the conversion factor 0.000277778.

What does 21 arc seconds look like in degrees?

21 arc seconds equals 0.0058333 degrees, a conversion used in navigation, trigonometry, and engineering design.

How do you calculate 21 arc seconds to degrees?

Multiply 21 by the conversion factor 0.000277778. The calculation is 21 × 0.000277778 = 0.0058333 degrees. This factor is defined by international measurement standards.

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21 arc seconds = 0.00583333 degrees
21 arc seconds = 0.00583333 degrees — conversion chart

Nearby Conversions

11 arc seconds0.003056 degrees 12 arc seconds0.003333 degrees 13 arc seconds0.003611 degrees 14 arc seconds0.003889 degrees 15 arc seconds0.004167 degrees 16 arc seconds0.004444 degrees 17 arc seconds0.004722 degrees 18 arc seconds0.005 degrees 19 arc seconds0.005278 degrees 20 arc seconds0.005556 degrees 22 arc seconds0.006111 degrees 23 arc seconds0.006389 degrees 24 arc seconds0.006667 degrees 25 arc seconds0.006944 degrees 26 arc seconds0.007222 degrees 27 arc seconds0.0075 degrees 28 arc seconds0.007778 degrees 29 arc seconds0.008056 degrees 30 arc seconds0.008333 degrees 31 arc seconds0.008611 degrees

For general conversions between arc seconds and degrees, see the arc seconds to degrees converter.

Conversion factors verified against BIPM, ISO 80000-3 1 turn = 2π rad = 360° (exact, ISO 80000-3). Last reviewed: March 2026
Adilson Fernandes By Adilson Fernandes
Tiago Fernandes Reviewed by Tiago Fernandes

All unit conversions on CoolConversion use conversion factors defined or documented by internationally recognised standards bodies (such as ISO and NIST), including both SI and non-SI units.