EPHEMERIS is the high precision ephemeris developed by
Astrodienst, largely based upon the DExxx ephemerides from NASA's
JPL . The original release in 1997 was based on the DE405/406
ephemeris. Since release 2.00 in February 2014, it is based on the
DE431 ephemeris released by JPL in September 2013.
can license the Ephemeris library. Ephemeris users find more than
8000 years of read-made printable files of ephemerides, containing
tens of thousands print pages in PDF quality.
Ephemeris offers these advantages:
Swiss Ephemeris is based upon the planetary and lunar ephemeris
DE431 developed by NASA's Jet Propulsion Laboratory. It covers the
time range 13201 BC to AD 17191. These data have been further
compressed with sophisticated compression techniques
developed by Astrodienst. This compressed ephemeris reproduces the
JPL data with 0.001 arcseconds precision. The Swiss Ephemeris files
for the planets without the Moon take up 27 Mb disk space, the
files for the Moon take up 70 Mb, totally 97 Mb disk space. The
original JPL file takes up 2788 Mb disk space.
transformation steps from the inertial timeframe of the JPL
DE430/431 integration to the reference frame for astrological
coordinates (true equinox of date), all corrections like
relativistic aberration, deflection of light in the gravity field
of the Sun etc. have been performed with utmost care and precision
so that the target precision of 0.001 arcsec
is maintained through all transformation steps. Never before has
such a high precision ephemeris been available to astrologers.
Ephemeris contains three ephemerides.
The user can choose whether he/she wants to use the original JPL
DE431 data (if available at his/her site), the compressed Swiss
Ephemeris data (the default) or a built in semianalytic theory by
Steve Moshier. The Swiss Ephemeris package switches automatically
to the available best precision ephemeris dependent on which
installed ephemeris files it finds. Even without any stored
ephemeris files, using the Moshier model, planetary positions with
better than 0.1 seconds of arc precision are available (3 arcsec
for the Moon). The Moshier ephemeris is based on DE404 and covers
the time range 3000 BC – 3000 AD.
addition to the astronomical planets as contained in the JPL
integration, we have included all other
bodies and hypothetical factors which are of interest to the
astrologer. We have used our own numerical integration
program to provide ephemerides for all known asteroids, once they
are officially numbered. There are, at the time of this writing in
February 2014, over 385'000 of them and nobody will be able to use
them all. We distribute these extended asteroid files via the
The Swiss Ephemeris is precise and fast.
On our Linux test machine, we compute 10'000 complete sets of
planetary positions, i.e. 10'000 x 11 planets, in less than 3
seconds. This is 0.3 milliseconds for the complete set of exact
planetary positions (consecutive 1 day steps).
license the Swiss Ephemeris:
Ephemeris is not a product for end users. It is a toolset for
programmers to build into their astrological software.
Ephemeris is made available by its authors under a dual licensing
system. The software developer, who uses any part of Swiss Ephemeris
in his or her software, must choose between one of the two license
models, which are
must be made before the software developer distributes software
containing parts of Swiss Ephemeris to others, and before any public
service using the developed software is activated.
developer choses the GNU GPL software license, he or she must
fulfill the conditions of that license, which includes the
obligation to place his or her whole software project under the GNU
GPL or a compatible license.
developer choses the Swiss Ephemeris Professional license, he must
follow the instructions below and purchase
the Swiss Ephemeris Professional Edition from Astrodienst and sign
the corresponding license contract.
License grants you the right to use, copy, modify and redistribute
Swiss Ephemeris, but only under certain conditions described in the
License. Among other things, the License requires that the copyright
notices and this notice be preserved on all copies.
the Swiss Ephemeris: Dieter Koch and Alois Treindl
authors of Swiss Ephemeris have no control or influence over any of
the derived works, i.e. over software or services created by other
programmers which use Swiss Ephemeris functions.
of the authors or of the copyright holder (Astrodienst) must not be
used for promoting any software, product or service which uses or
contains the Swiss Ephemeris. This copyright notice is the ONLY
place where the names of the authors can legally appear, except in
cases where they have given special permission in writing.
of licenses include the right to use the label 'Swiss Ephemeris
Inside' on products.
If you want the Swiss Ephemeris Professional
License for your software project, please proceed as follows:
the licensing contract in two copies
the printed copies out and sign them
them (not email, but real paper) to Astrodienst AG, Dammstr. 23,
8702 Zollikon, Switzerland.
not forget the credit card details (if you live outside D,CH,A
where we deliver with invoice)
will countersign the contract and send it to you. We will charge
your credit card when we send the signed contract.
you are in a hurry, you can fax the contract to us, and we will
send a signed copy by post, and charge the credit card immediately.
want the Swiss Ephemeris Free Edition
for your software project, please proceed as follows:
Ephemeris documentation consists of two parts.
General Manual describes our work and
the technical background.
Programmer's Manual describes the
implementation details and the programming interface to the DLL
resp. library functions.
Programs can be downloaded from
. A utility unzip.exe is also provided to unpack the download
is a Windows program which computes complete horoscopes including
houses and asteroids.
is a command line Windows program which computes planetary
positions. It is very versatile and can be used to create tables of
ephemerides, or other tabular data for export to Excel and similar
Issue the command
to get information
about the features of swetest.
Authors: Dieter Koch and Dr. Alois Treindl