ZET - Astrology Software - User's Manual - Swiss Ephemeris

Swiss Ephemeris

ZET has a Swiss Ephemeris module licensed from Astrodienst.

The main Swiss Ephemeris files, distributed in the ZET Lite download, are the following:

- swdll32.dll - calculation module. This file must be located in either the main ZET folder (installation default), or in Windows' System folder,
- sepl_18.se1 - planets' ephemeris files for the date range from 1800 to 2399 A.D. This and the files belows should be located in the [ZET]\Swiss folder,
- semo_18.se1 - Moon ephemeris file for the same date range,
- seas_18.se1 - Main asteroids ephemeris file (Ceres, Pallas, Juno, Vesta, Chiron, Pholus) for the same date range.

You can find a comlete description of the Swiss Ephemeris at www.astro.com.

Here is a brief extract about the ephemeris and its component files, by its authors:

The core part of Swiss Ephemeris is a compression of the JPL-Ephemeris DE406. Using a sophisticated mechanism, we succeeded in reducing JPL's 200 MB storage to only 18 MB. The agreement with DE406 is within 1 milli-arcsecond (0.001). Since the inherent uncertainty of the JPL ephemeris for most of its time range is much greater, Swiss Ephemeris should be completely satisfying even for computations demanding very high accuracy.

The time range of the JPL ephemeris is 3000 BC to 3000 AD or 6000 years. We have extended this time range to 10'800 years, from 2 Jan 5401 BC to 31 Dec 5399. The details of this extension are described below in section 2.1.5.

Each Swiss Ephemeris file covers a period of 600 years; there are 18 planetary files, 18 Moon files and 18 main-asteroid files for the whole time range of 10'800 years.

The file names are as follows:

Planetary file | Moon file | Main asteroid file | Time range
seplm54.se1 | semom54.se1 | seasm54.se1 | 5401 BC 4802 BC
seplm48.se1 | semom48.se1 | seasm48.se1 | 4801 BC 4202 BC
seplm42.se1 | semom42.se1 | seasm42.se1 | 4201 BC 3602 BC
seplm36.se1 | semom36.se1 | seasm36.se1 | 3601 BC 3002 BC
seplm30.se1 | semom30.se1 | seasm30.se1 | 3001 BC 2402 BC
seplm24.se1 | semom24.se1 | seasm24.se1 | 2401 BC 1802 BC
seplm18.se1 | semom18.se1 | seasm18.se1 | 1801 BC 1202 BC
seplm12.se1 | semom12.se1 | seasm12.se1 | 1201 BC 602 BC
seplm06.se1 | semom06.se1 | seasm06.se1 | 601 BC 2 BC
sepl_00.se1 | semo_00.se1 | seas_00.se1 | 1 BC 599 AD
sepl_06.se1 | semo_06.se1 | seas_06.se1 | 600 AD 1199 AD
sepl_12.se1 | semo_12.se1 | seas_12.se1 | 1200 AD 1799 AD
sepl_18.se1 | semo_18.se1 | seas_18.se1 | 1800 AD 2399 AD
sepl_24.se1 | semo_24.se1 | seas_24.se1 | 2400 AD 2999 AD
sepl_30.se1 | semo_30.se1 | seas_30.se1 | 3000 AD 3599 AD
sepl_36.se1 | semo_36.se1 | seas_36.se1 | 3600 AD 4199 AD
sepl_42.se1 | semo_42.se1 | seas_42.se1 | 4200 AD 4799 AD
sepl_48.se1 | semo_48.se1 | seas_48.se1 | 4800 AD 5399 AD

You can obtain these files from ftp://ftp.astro.ch/pub/swisseph/ephe/.

To download and install additional asteroids files, see Catalog of Asteroids.

If you already have astrology software which installed Swiss Ephemeris files, you do not need to retain ZET's copy of them. They can be accessed by ZET if you specify a path to them (see General Settings).