Second of Arc to Minute of Arc Conversion Chart
| Second of arc (arcsec) | Minute of arc (arcmin) | Reference Benchmark | Formula Step |
|---|---|---|---|
| 1 arcsec | 0.0167 arcmin | One Arcsecond Astronomical Stellar Parallax Baseline | 1 × 0.016667 = 0.0167 arcmin |
| 3 arcsec | 0.05 arcmin | Three Arcseconds High-Resolution Optical Guide Camera Drift | 3 × 0.016667 = 0.05 arcmin |
| 6 arcsec | 0.1 arcmin | Six Arcseconds Planetary Disc Detail Separation Angle | 6 × 0.016667 = 0.1 arcmin |
| 15 arcsec | 0.25 arcmin | Quarter Arcminute Mars Opposition Apparent Diameter | 15 × 0.016667 = 0.25 arcmin |
| 30 arcsec | 0.5 arcmin | Thirty Arcseconds Half Arcminute Standard Calibration Grid | 30 × 0.016667 = 0.5 arcmin |
| 60 arcsec | 1 arcmin | Exact International Definition of Sixty Arcseconds in Arcminute | 60 × 0.016667 = 1 arcmin |
| 120 arcsec | 2 arcmin | Two Arcminutes Binary Star Visual Separation Angle | 120 × 0.016667 = 2 arcmin |
| 300 arcsec | 5 arcmin | Five Arcminutes Open Star Cluster Core Diameter | 300 × 0.016667 = 5 arcmin |
| 600 arcsec | 10 arcmin | Ten Arcminutes Large Globular Cluster Angular Span | 600 × 0.016667 = 10 arcmin |
| 900 arcsec | 15 arcmin | Quarter Degree Fifteen Arcminutes Planetary Nebula Halo | 900 × 0.016667 = 15 arcmin |
| 1800 arcsec | 30 arcmin | Thirty Arcminutes Full Moon Apparent Diameter in Arcseconds | 1800 × 0.016667 = 30 arcmin |
| 2700 arcsec | 45 arcmin | Forty-Five Arcminutes Three-Quarter Degree Optical FOV | 2700 × 0.016667 = 45 arcmin |
| 3600 arcsec | 60 arcmin | One Degree Sixty Arcminutes Exactly 3,600 Arcseconds | 3600 × 0.016667 = 60 arcmin |
| 5400 arcsec | 90 arcmin | One and a Half Degrees Ninety Arcminutes Field Sector | 5400 × 0.016667 = 90 arcmin |
| 10800 arcsec | 180 arcmin | Three Degrees One Hundred Eighty Arcminutes Astrophoto Field | 10800 × 0.016667 = 180 arcmin |
Second of arc to Minute of arc Formula & Unit Definitions
The conversion from seconds of arc to minutes of arc is governed by the exact rational factor of 1/60 (1 arcsec = 1/60 arcmin ≈ 0.0166667 arcmin). To convert arcseconds into arcminutes, divide the arcsecond value by 60 (or multiply by ~0.016667). Conversely, to convert arcminutes into seconds of arc, multiply by 60.
Quick Estimation: Divide the arcsecond value by 6, then shift the decimal point one place left (divide by 60). For instance: 30 arcsec / 60 = 0.5 arcmin; 60 arcsec / 60 = 1 arcmin; 120 arcsec / 60 = 2 arcmin; 1,800 arcsec / 60 = 30 arcmin.
Second of Arc (arcsec / ″)
Fine Sexagesimal Division (1/3,600°)- Creator & Origin: Ptolemaic sexagesimal geometry and 19th-century astronomical micrometer screws.
- Standard Definition: Defined as exactly 1/60 of a minute of arc (1 arcsec = 1/60 arcmin).
- Everyday Focus: Astronomical seeing, telescope resolution limits, CCD pixel scales, and stellar wobble.
Minute of Arc (arcmin / ′)
Sexagesimal Sub-Division (1/60°)- Creator & Origin: Babylonian base-60 mathematics and Ptolemy's first sexagesimal circle division.
- Standard Definition: Defined as 1/60 of a degree (60 arcsec = 1 arcmin, 1 nautical mile of latitude).
- Everyday Focus: Rifle scope MOA clicks, planetary nebula angular diameters, and optical fields of view.
Frequently Asked Questions
Q.How many minutes of arc are in one second of arc?
One second of arc equals exactly 1/60 of a minute of arc (approximately 0.0166667 arcmin).
Q.What is the reverse conversion from arcminutes to arcseconds?
To convert back, use the Minute of Arc to Second of Arc Converter where 1 arcmin equals 60 arcsec.
Q.How many arcminutes is 1,800 arcseconds?
1,800 arcseconds equals exactly 30 arcminutes (half a degree).
Q.How many arcminutes is 60 arcseconds?
60 arcseconds equals exactly 1 arcminute.
Q.How do you convert arcseconds to arcminutes without a calculator?
Divide the number of arcseconds by 60 (e.g. 150 arcsec / 60 = 2.5 arcmin).