Sunlit Design > InfoSearch > Time Basis of Astronomical Calculations
Index: A-D, E-R, S-Z
A
- Accuracy of Sundials
- A.D. Years
- Altitude, Solar
- Angle above Horizon, Solar
- Apparent Time
- "Astronomical Algorithms"
- Astronomical Calculations, Time Basis of
- Azimuth, Solar
- Daylight Saving Time
- Declination, Solar
- Degrees, Minutes and Seconds
- Degrees of Rotation
- Dynamical Time
Time Basis of Astronomical Calculations
Since 1930 it has been recognised that the GMT/UT time scale is not uniform enough for astronomical calculations. Since that time the Dynamical Time scale has been developed which is based on atomic time and which is much more uniform than time scales derived from the rotation of the earth.Calculate it!
The Sun API converts all times to Dynamical Time before calculating astronomical values. If the result of the calculation is a point of time (e.g. the time of the occurrence of an Equinox) then it is converted back to UT before the answer is returned by the user function.