|Warning||The OrbFit software system is
growing in complexity and scope: to keep up with this growth, this web
site also needs to be completely restructured. Please be patient while
work is in progress.
OrbFit has undergone another major upgrade.
The new version 5.0 results from the merge of the previous
operational version 4.2, including the new astrometric error model and
various other improvements, with the version 4.3 which has never been
distributed because was under test. In practice, the capabilities from
4.3 which have been incorporated include the capability to determine
the semiempirical parameters appearing in the non-gravitational
perturbations on asteroids, such as the direct radiation
pressure and the Yarkovsky effect. Thus covariance matrices can be up to 8x8, rather
than just 6x6. Of course solution without nongrav are still possible,
but please note that the format for the orbits and covariances has
been updated to make room for the new dynamical parameters and their
OrbFit has recently exceeded the 215,000 lines of Fortran95. Also for
this reason, it has been necessary to maintain the split of the global
|Requirements||The software we are providing has been developed under LINUX and is distributed in a package allowing for automatic compilation on whatever target computer with a LINUX operating system; compilation is possible under the free Fortran95 compiler gfortran, although we mostly use the commercial compilers Intel and Lahey. Installation under some other dialect of UNIX (e.g., BSD, HPUX, Mac OS 10 and later) should be straightforward for an expert user. We are sorry, but we are currently not equipped for distributing OrbFit in a Windows version, although we see no reason why the Intel compiler would not be able to compile OrbFit also under Windows.|
|Where can I learn more?|| You can use the online help here, but this document needs to be
updated. You may also go directly to our online OrbFit distribution directory. After compiling the code,
you can access the OrbFit main programs through the OrbFitSoft
graphical interface, available in the ./doc directory.
We have abandoned the original idea of writing a mathematical specification document for OrbFit, because it would be huge and hard to maintain, even assuming we had the time of writing it, which has not been the case so far. However, we have written a textbook Theory of Orbit Determination , by A. Milani and G.F. Gronchi, Cambridge University Press, 2010 (index of this book). The content of this book covers most of the subjects which are needed to understand the working of OrbFit. The copyright for this book has been given to the publisher, thus we cannot make the full text available on the web: we are progressively making available appendixes, comments, errata corrige, and other related material on this site here.
|Where can I get OrbFit in Fortran 90/95?||You can download the OrbFit distribution for UNIX . However, please note this is the latest version 5.0, which has an important new feature, the possibility of computing orbits with dynamical parameters connected to non-gravitational perturbations. For this purpose we had to change the format of the orbits. The data from AstDyS and NEODyS already have this new feature; to use the orbit files from these sources, it is necessary to use version 5.0 and later.|
|Who maintains OrbFit?||The OrbFit Consortium.|