Skip to main content

A rewrite of IOP3, a pipeline to work with photometry and polarimetry of optical data from CAHA and OSN.

Project description


IOP4 is a complete rewrite of IOP3, a pipeline to work with photometry and polarimetry of optical data from CAHA and OSN observatories. It is built to ease debugging and inspection of data.

IOP4 implements Object Relational Mapping (ORM) to seamlessly integrate all information about the reduction and results in a database which can be used to query and plot results, flag data and inspect the reduction process in an integrated fashion with the whole pipeline. It also ships with an already built-in web interface which can be used out of the box to browse the database and supervise all pipeline processes.


We recommend installing IOP4 in an isolated environtment as described below. IOP4 is hosted in PyPI software repository.

Option 1: Using a virtual environment

Note: IOP4 requires Python 3.10 or later. You can check your Python version with python --version. If you have a compatible version, you can skip this step.

If you don't have Python 3.10 or later, you can install pyenv and pyenv-virtualenv, which will manage python versions for you. You can use the automatic installer pyenv-installer:

    $ curl | bash

Follow the instructions that this command outputs to add pyenv to PATH (or copy the commands from for your shell). Restart your terminal, or source the file (e.g. . ~/.bashrc or . ~/.zshrc) Then, run

    $ pyenv install 3.10
    $ pyenv virtualenv 3.10 iop4-venv
    $ pyenv activate iop4-venv

Now you will have a virtual environment with the right Python version, and you can continue with the next step. To deactivate, just run pyenv deactivate.

With the environment activated, you can install IOP4 latest version by running:

    $ pip install iop4

Alternatively, you can clone this repository and install IOP4:

    $ git clone ''
    $ cd iop4
    $ pip install .

or pip install -e . if you want to install it in developer mode.

Option 2: Using conda/mamba

As the previous option, create and activate the environment as follows:

    $ conda create -n iop4 python=3.10
    $ conda activate iop4

Then run:

    $ pip install iop4

Alternatively, you can also clone this repository and run (inside the root directory of the cloned repository):

    $ pip install .

or pip install -e . if you want to install it in developer mode.

If you followed the steps in any of the two options above, you will have installed the module iop4lib and the iop4 command, and the iop4site project.


After installation, take a look at the example configuration file (config/config.example.yaml), set the appropriate variables (path to the database, data directory, astrometry index files path, credentials, etc) and rename it to config/config.yaml.

Running Tests

To run the tests, first follow the previous steps to configure IOP4. At the moment, you will also need to download the iop4testdata.tar.gz file manually and place it under your home directory. Then, run

    $ pytest -vxs tests/

If it is the first time executing IOP4, the astrometry index files will be downloaded to astrometry_cache_path (see config/config.example.yaml). This will take some time and a few tens of GB, depending on the exact version.

Warning: in some macOS systems, the process might hang up. Execute export OBJC_DISABLE_INITIALIZE_FORK_SAFETY=YES or add that line to your shell init script.


If no previous database exists, make sure to create it. You can do it automatically from the iop4site/ directory by using

    $ python makemigrations
    $ python migrate

Then, create a user with

    $ python createsuperuser

You can later use these credentials to login to the admin site, where you will need to add any sources of interest to the empty catalog.

To manually back up all data from the DB, you can use

    $ python dumpdata --natural-primary --natural-foreign --format=yaml > priv.dumps.yaml

This file can be used to reload the data to the DB with:

    $ python loaddata priv.dumps.yaml

An utility script, iop4site/, is provided which will completely reset the DB keeping catalog and users data.

As A Program

The pipeline script iop4 can be invoked as

    $ iop4 --epoch-list tel1/yymmdd tel2/yymmdd

to download and reduce the epoch yymmdd from telescopes tel1 and tel2 respectively. For example: iop4 -l T090/230430.

To serve the results in Django debug server, change to the iop4site directory and run

    $ python runserver

although this server is only recommended for debugging purposes, and you should use another server in production (see Django documentation).

As A Library

iop4lib uses django ORM and it needs to be configured before using it. Therefore, you should do

    import iop4lib

once at the start of your script. IOP4 configuration can be accessed anywhere without configuring the ORM doing import iop4lib; iop4conf = iop4lib.Config(config_db=False).

This way of configuring IOP4 should be also valid inside IPython Shell, but not for Jupyter notebooks, since their asynchronous output interferes with Django ORM. To use IOP4 inside a notebook, see below. More details can be found in the documentation for iop4lib.Config.

Now you are ready to import and use IOP4 models from your Python script, e.g:

    import iop4lib
    from iop4lib.db import RawFit, ReducedFit, Epoch, PhotoPolResult

    # this will print the number of T220 nights reduced:

    # this will reduce the last T220 night:

In Interactive Notebooks (JupyterLab)

You can use IOP4 in an interactive manner inside a Jupyter notebook. The following lines also activate matplotlib's graphical output (deactivated by default, as some plots may be generated inside the server).

%autoawait off
%load_ext autoreload
%autoreload all

import iop4lib.config
iop4conf = iop4lib.Config(config_db=True, gonogui=False, jupytermode=True)   


You can get an IPython interactive terminal after running iop4 using the -i option. You can override any config option using the -o option, e.g.:

    $ iop4 -i -o nthreads=20 -o log_file=test.log --epoch-list T090/230313 T090/230317


To build and show the documentation, run

    $ make docs-sphinx
    $ make docs-show


You are welcome to contribute to IOP4. Fork and create a PR!

Citing IOP4

If you use IOP4, or any result derived from it, we kindly ask you to cite the following references:


You can use the following BibTeX entry:

  author       = {Escudero Pedrosa, Juan and
                  Morcuende Parrilla, Daniel and
                  Otero-Santos, Jorge},
  title        = {IOP4},
  month        = mar,
  year         = 2024,
  publisher    = {Zenodo},
  version      = {v1.0.0},
  doi          = {10.5281/zenodo.10222722},
  url          = {}

This might change in the future, as IOP4 is still under the process of being published in a peer-reviewed journal. Check this repository for updates :)

Project details

Download files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

Source Distribution

iop4-1.1.1.tar.gz (231.6 kB view hashes)

Uploaded Source

Built Distribution

iop4-1.1.1-py3-none-any.whl (209.1 kB view hashes)

Uploaded Python 3

Supported by

AWS AWS Cloud computing and Security Sponsor Datadog Datadog Monitoring Fastly Fastly CDN Google Google Download Analytics Microsoft Microsoft PSF Sponsor Pingdom Pingdom Monitoring Sentry Sentry Error logging StatusPage StatusPage Status page