Accuracy is good for present time (i.e. +- a few days from now), but degrades quickly with time (for planets, satellites etc..). For the online version we can't

Accuracy is good for present time (i.e. +- a few days from now), but degrades quickly with time (for planets, satellites etc..). For the online version we can't afford to use full planetary models (like in the desktop version) as it would be too much data to download at startup.