hour angle
Angleexact by definition
An hour of angle is exactly 1/24 of a full turn, 15 degrees or π/12 radians. Right ascension and hour angle in astronomy are measured in hours, minutes and seconds of time rather than degrees, because the sky turns through 15 degrees every hour and a coordinate in hours can be compared directly against a clock.
Watch out: A minute of right ascension is 15 arcminutes, not one, and a second of right ascension is 15 arcseconds. Mixing time-based and arc-based subdivisions is the most common error in reading a coordinate: a position given as 12ʰ 30ᵐ is 187.5 degrees, not 12.5.
| 1 | 15 |
One hour angle in every angle unit
| 54,000,000,000 | microarcsecond (μas) | |
| 54,000,000 | milliarcsecond (mas) | |
| 261,799 | microradian (μrad) | |
| 54,000 | arcsecond (″) | |
| 900 | arcminute (′) | |
| 266.667 | mil (NATO) (mil) | |
| 261.799 | milliradian (mrad) | |
| 16.6667 | gradian (gon) | |
| 15 | degree (°) | |
| 1.33333 | compass point (point) | |
| 1 | hour angle (h)this unit | |
| 0.261799 | radian (rad) | |
| 0.166667 | quadrant (quad) | |
| 0.0416667 | revolution (rev) |
Solvers that use angle