- Package: libTheSky
- Description: Fortran library to compute properties of objects in The Sky
- Homepage: https://libthesky.sourceforge.net
- Copyright: Copyright (c) 2002-2025 Marc van der Sluys - Nikhef/Utrecht University - marc.vandersluys.nl
The package libTheSky provides a Fortran library to compute the positions and other properties of celestial bodies (Moon, planets, comets, asteroids, stars), events (e.g. lunar phases) and coordinate transformations. It forms the core of the software that is used to create the Dutch popular-astronomy website https://hemel.waarnemen.com. To download the libTheSky package, read the code documentation, or to contact the developer, see: https://libthesky.sourceforge.net/
libTheSky is written in Fortran, hence you will need a Fortran compiler. Gfortran, part of gcc, is a free, open-source Fortran compiler included in many GNU/Linux distributions and available from https://gcc.gnu.org/fortran/.
The default installer uses CMake to configure and compile the code. CMake is also open-source software, also included in most GNU/Linux distributions, and can be downloaded from https://www.cmake.org/. Alternatively, you can create your own Makefile or compile and link the code manually.
libTheSky needs the Fortran library libSUFR in order to compile and run. libSUFR is free and open software, and available under the EUPL v1.2 from https://libsufr.sf.net/.
After downloading from libthesky.sf.net, you can unpack the tarball and cd into its directory by doing e.g.:
tar xfz libthesky-0.0.1.tar.gz
cd libthesky-0.0.1/(replace “0.0.1” with the correct version number).
To configure, compile and install the code and data files (in the CMake (not Linux! - see below) default
system directories /usr/local/...), from the main package directory (the one that contains the file
CMakeLists.txt), do:
mkdir build && cd build/
cmake ..
make
sudo make installThe second step above configures the code and should find your Fortran compiler and libSUFR. The third step compiles and links the code, and the last step installs it on your system - for which you need root priveliges, hence the ‘sudo’ command.
To install the package in a specific system directory, e.g. the Linux default /usr/... (RECOMMENDED), do:
mkdir build && cd build/
cmake -DCMAKE_INSTALL_PREFIX:PATH=/usr ..
make
sudo make installTo install the package in your own user directory, you won’t need root priveliges, can omit the ‘sudo’ command and combine the last two commands, e.g.:
mkdir build && cd build/
cmake -DCMAKE_INSTALL_PREFIX:PATH=/home/me/usr ..
make installTo compile the code with your favourite compiler (in case you have several installed), prepend the cmake line
with e.g. FC=gfortran:
FC=gfortran cmake ..If you have multiple cores or processors, you can speed up the make step by specifying the number of parallel build jobs using the -j option. E.g., for four cores, you can have four parallel jobs and use:
make -j4To compile the code without installing it anywhere, leave out the install step
mkdir build && cd build/
cmake ..
makeThe compiled libraries and modules can then be found in the usr/ subdirectory of the package dir.
On a Linux system, the library and module files could be installed as:
/usr/lib/libTheSky.* /usr/include/libTheSky/*.mod
If you want to use the libraries with multiple Fortran compilers, you will want to keep the different versions of the library separated. In this case, use (in addition to any other options):
cmake -DCOMPILER_SPECIFIC_LIBS=on ..The library files will then be installed as:
/usr/lib/libTheSky_<NameOfFortranCompiler>.* /usr/include/libTheSky/<NameOfFortranCompiler>/*.mod
If one of your Fortran compilers is your default, you can use both the default installation method and the compiler-specific method to install the library.
The data files are distributed in a separate tarball, named libthesky-data-<YYYYMMDD>.tar.bz2. They will
unpack into the data/ subdirectory of the package and the code will expect to find them in
/usr/shared/libTheSky/ by default. Hence, to install the data files manually, do e.g.:
tar xfj libthesky-data-<YYYYMMDD>.tar.bz2
sudo mkdir /usr/shared/libTheSky/
sudo cp -vi data/* /usr/shared/libTheSky/Alternatively, you can use the libTheSky_data target in the CMake file of the source code, by copying the data files into that package’s subdirectory before compiling it, and making sure you install the data files as well:
tar xfz libthesky-<0.0.1>.tar.gz
tar xfj libthesky-data-<YYYYMMDD>.tar.bz2
mv data libthesky-0.0.1/
cd libthesky-0.0.1/
...
sudo make libTheSky_data installAll data files needed to use libTheSky are provided in the tarball. The file asteroids.dat is a reduced
version of the file https://ssd.jpl.nasa.gov/dat/ELEMENTS.NUMBR.gz, containing all bodies with H<15 and a<100
AU (~25% of total, ~90,000 objects). If you want to use the full/latest version instead, do something like:
.$ wget https://ssd.jpl.nasa.gov/dat/ELEMENTS.NUMBR.gz -O - | gunzip -c > data/asteroids.datIf you run into problems or have questions, please feel free to contact Marc van der Sluys by email through https://marc.vandersluys.nl.
Copyright (c) 2002-2025 Marc van der Sluys - Nikhef/Utrecht University - marc.vandersluys.nl
This file is part of the libTheSky package, see: https://libthesky.sf.net/
This is free software: you can redistribute it and/or modify it under the terms of the European Union Public Licence 1.2 (EUPL 1.2). This software is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the EU Public Licence for more details. You should have received a copy of the European Union Public Licence along with this code. If not, see https://www.eupl.eu/1.2/en/.