Quote:
Originally Posted by stephend
I want to write a program to calculate moonrise time and phase, so that this can be displayed in a website automatically far into the future.
By far into the future I mean a few years, so I can take the moon's current orbit as being fixed, even though it isn't.
Since its orbit is currently close to circular, I can treat each day's worth of orbit as being equal to every other.
I assume using the average synodic month will be okay, hoping that the average figure is quite accurate over say every year rather than say every century.
Any helpful hints, comments, would be  |
Unfortunately the Moon's orbit does not give repeatable data. It's the classic three body problem of Celestial Mechanics (Sun, Earth, Moon).
The main culprit is Nutation where the combined gravitational effects of the Sun and the Moon cause an oscillation in the Earth's axis of rotation. This effect is quite rapid as one complete oscillation takes less than 19 years.
Regards
Steven