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).