Installation Instructions

Note

Prerequisites:

All that is required is a reasonably current version of the LSST science pipelines and of the skyCatalogs package. However, in order to generate catalogs for a particular object type some suitable source catalog must be read. Depending on the format of that catalog, you may need to install an additional library or two.

Installation steps common to all object type

Note

These instructions are similar to imSim installation instructions. If you’ve installed imSim already you can skip everything in this section except the installation of skyCatalogs_creator itself and ensuring you have a new enough version of skyCatalogs.

Installing LSST science pipelines

There are several methods of installation. Only the simplest (using a prebuilt cvmfs version) is described here. For other methods, see the imSim installation instructions.

If you are working at the USDF (Rubin Project computing) or at NERSC (DESC computing), perhaps the easiest way to setup and use skyCatalogs_creator is to rely on the prebuilt versions of the pipelines contained in the cvmfs distribution which is installed there. This solution is also appropriate for personal laptops and university/lab based computing systems if you are able to install the cvmfs system.

The CernVM file system (cvmfs) is a distributed read-only file system developed at CERN for reliable low-maintenance world-wide software distribution. LSST-France distributes weekly builds of the Rubin science pipelines for both Linux and MacOS. Details and installation instructions can be found at sw.lsst.eu . The distribution includes conda and skyCatalogs dependencies from conda-forge along with the science pipelines.

Load and setup the science pipelines

First you need to setup the science pipelines. This involves sourcing a setup file and then using the Rubin eups commands to set them up.

Note

Version w_2025_49 or later of the science pipelines is recommended. This will guarantee other dependencies of skyCatalogs, such as GalSim, are new enough.

Also note: the cvmfs distribution is a read-only distribution. This means you cannot add packages to the included conda environment and packages you install via pip will be installed in the user area. If you need a conda environment you will need to use a different installation method.

Source the appropriate setup script (note the -ext in the name) and then setup the distribution (if you are on MacOS use darwin-x86_64 instead of linux-x86_64).

source /cvmfs/sw.lsst.eu/almalinux-x86_64/lsst_distrib/w_2025_28/loadLSST-ext.bash
setup lsst_distrib

Install skyCatalogs

Clone the skyCatalogs package from GitHub. Here we assume you are in your installation directory SKYCATALOGS_HOME as described in the section Per-session setup below.

git clone https://github.com/LSSTDESC/skyCatalogs

at this point if you would only like to use skyCatalogs you can pip install skyCatalog/ however we instead suggest using the eups tool to simply setup the package for use without installing it. This will allow you to edit the package in place, use multiple versions, change branches etc. You should definitely do this if you plan to do any skyCatalogs or skyCatalogs_creator development.

If you do not intend to do any development you may choose instead to clone or pip install the most recent release tag. It should be at least v2.4.0.

git clone https://github.com/LSSTDESC/skyCatalogs.git --branch v2.4.0

or

pip install skyCatalogs

Creating trilegal catalogs

In order to create trilegal catalogs you need to install the pystellibs and astro-datalab packages. You can do something like this:

git clone https://github.com/mfouesneau/pystellibs.git
cd pystellibs
pip install  --user --no-deps --nobuild-isolation  .
cd ..
pip install --no-build-isolation --no-deps astro-datalab

Install skyCatalogs_creator

git clone https://github.com/LSSTDESC/skyCatalogs_creator.git

Install needed data files

Go to your SKYCATALOGS_HOME directory and download some needed data files (you will only need to do this once).

mkdir -p rubin_sim_data/sims_sed_library
curl https://s3df.slac.stanford.edu/groups/rubin/static/sim-data/rubin_sim_data/throughputs_2023_09_07.tgz | tar -C rubin_sim_data -xz
curl https://s3df.slac.stanford.edu/groups/rubin/static/sim-data/sed_library/seds_170124.tar.gz  | tar -C rubin_sim_data/sims_sed_library -xz

Per-session setup

Every session you will need to initialize the lsst pipelines distribution and define a SKYCATALOGS_HOME directory where other needed files (see e.g. section Install needed data files) go:

source /cvmfs/...            # as above
setup lsst_distrib

export SKYCATALOGS_HOME=*PUT YOUR INSTALL DIRECTORY HERE*
setup -k -r $SKYCATALOGS_HOME/skyCatalogs

# For data files
export RUBIN_SIM_DATA_DIR=$SKYCATALOGS_HOME/rubin_sim_data
export SIMS_SED_LIBRARY_DIR=$SKYCATALOGS_HOME/rubin_sim_data/sims_sed_library

If you’re creating trilegal catalogs you also need to make pystellibs and the Astro Datalab software accessible. You may need to do something like this:

export PYTHONPATH=${SKYCATALOGS_HOME}/pystellibs/src:${PYTHONPATH}

Using skyCatalogs_creator

For object types handled by this package, the ouput catalog files are of two types: main files and flux files. For the most part main files contain quantities directly read from an upstream source, including everything needed to compute fluxes. The flux files are created in a separate step, using the information stored in the main files.

To create main files, use the script create_main.py in subdirectory skycatalogs_creator/scripts. For flux files use create_flux.py. To see what options are available type

python skycatalogs/creator/scripts/create_main.py --help
python skycatalogs/creator/scripts/create_flux.py --help

See also the page “Creating New Catalogs” in this site.