Installation

Requirements

Python 3.11 or newer.
wcc_etc 0.6.0 or newer — the WCC exposure time calculator. It is not on PyPI; install it from source first (see below).
The scientific stack pulled in automatically as dependencies: numpy, scipy, astropy, astroquery, and synphot.

Install from source

wcc-sim depends on wcc_etc for the instrument model, so install that first, then wcc-sim itself, both in editable mode so local changes to src/ are picked up immediately:

# 1. the instrument model
git clone git@github.com:schmidt-observatories/wcc-etc.git
pip install -e wcc-etc

# 2. the simulator
git clone git@github.com:schmidt-observatories/wcc-sim.git
cd wcc-sim
pip install -e .

Using a conda environment

The synphot / astropy / astroquery stack is happiest in a dedicated environment:

conda create -n wcc-sim python=3.13
conda activate wcc-sim
pip install -e <path-to-wcc-etc>
pip install -e .

Verify the installation

The quickest check runs a tiny noiseless simulation with a hand-made catalog (no network needed):

import numpy as np
from astropy.table import Table
from wcc_sim import simulate_field

cat = Table({
    "source_id": [1], "ra": [150.1], "dec": [2.2],
    "phot_g_mean_mag": [12.0], "phot_bp_mean_mag": [12.3],
    "phot_rp_mean_mag": [11.6],
})
field = simulate_field(150.1, 2.2, catalog=cat, shape=(512, 512),
                       add_noise=False)
print(field.image_e.sum())  # total source electrons

If that prints a large positive number, you are ready to go. Continue with Quick start. (The first real simulation also needs network access for the Gaia DR3 cone search — see Gaia catalogs for the on-disk cache.)

Running the test suite

The package ships with a pytest suite (no network required — Gaia queries are mocked):

pip install -e ".[test]"
pytest

Building the documentation locally

The documentation you are reading is built with Sphinx and the Read the Docs theme. The tutorial pages are rendered from the Jupyter notebooks via nbsphinx, which requires pandoc to be installed.

# from the repository root
pip install -e .                              # so autodoc can import the package
pip install -r docs/sphinx/requirements.txt   # Sphinx + theme + nbsphinx
# plus a pandoc binary, e.g.  conda install pandoc   or   brew install pandoc

cd docs/sphinx
make html

Open docs/sphinx/_build/html/index.html in a browser. To force a clean rebuild, run make clean html.