| About the NASA/JPL DE405 and USNO AE98 Ephemerides PHP Demo Programs by Jay Tanner - 2026 |
|
|
|
In spite of some contrary opinions, the NASA/JPL DE405 and USNO AE98 are NOT entirely obsolete.
For most amateur astronomers, they are generally sufficient for certain mundane tasks, such as computing the geocentric lunar phases or the local topocentric rising and setting times of astronomical bodies. However, I am slowly replacing some DE405 and USNO AE98 work with newer programs based on the NASA/JPL Horizons API for much improved accuracy. Asteroid orbits are somewhat unstable and need periodic updates and the Horizons API takes care of this task using the most recent data. |