Planetary ephemerides have been compressed using the best approximation in the Chebyshev sense. Using this uniform approximation we have got better compression than the one obtained when using other approximation procedures.
The application of the Schmitt algorithm to DE200/LE200 showed encouraging results: in each case the data base is recovered within the bound for the error provided by the algorithm. The approximating polynomials obtained can also be used for fast evaluation at interpolated points, but for the moon we were forced to deal with a dense data base.
Application of this uniform approximation to compact calculus of "Almanaque Náutico'' showed very reliable. This method will be implemented as part of the navigation system of the Spanish Navy.
We thank Dr. Deprit who suggested us the application of minimax methods to the compression of astronomical ephemerides. Thanks are due to Dr. Chapront for many comments and suggestions while acting as a referee. This work has been supported in part by the Spanish Ministry of Education (DGICYT Project # PB96-0522).