Development

No camera required — there is a simulator with a synthetic star field whose brightness responds to exposure and gain, so auto-exposure behaves as it does on real hardware.

git clone https://github.com/mattg8892/skylapse && cd skylapse
python3 -m venv venv && source venv/bin/activate
pip install -e ".[dev]"          # needs a C compiler: pidng ships as source
pytest

SKYLAPSE_SIM=1 \
SKYLAPSE_CONFIG=./dev/config.yaml \
SKYLAPSE_IMAGES=./dev/images \
SKYLAPSE_RUN=./dev/run \
  skylapse-daemon

The web interface builds with npm --prefix web install && npm --prefix web run build.

Installing onto a Pi you already have

Rather than flashing the image: clone the repo onto the Pi and run sudo ./install.sh. It installs system packages, builds the frontend and enables the three services, running Skylapse in place from the checkout — so updating is git pull && sudo systemctl restart skylapse-daemon. It is safe to re-run.

The SD image is this same script, run inside the image at build time (image/build.sh).

Environment variables

Three variables relocate everything:

Variable	Default on a rig	What it is
SKYLAPSE_CONFIG	/etc/skylapse/config.yaml	The single config file (atomic writes: tmp + fsync + rename)
SKYLAPSE_IMAGES	/var/lib/skylapse/images/	The image store, one folder per night, JSON sidecar per frame
SKYLAPSE_RUN	/run/skylapse/	Runtime status files: daemon heartbeat, netwatch state, latest frame path

SKYLAPSE_SIM=1 swaps the camera for the simulator.

Architecture

Three independent systemd services. A bug in one can never take down the others.

Service	Job
skylapse-daemon	Capture loop, camera drivers, JPEG/DNG pipeline, scheduling
skylapse-api	REST API and web interface (FastAPI + React)
skylapse-netwatch	Wi-Fi/access-point state machine over NetworkManager, and the fallback when Wi-Fi is gone

They share only the config file and the status files, so none can take another down. Design notes has the full reasoning, including what each camera taught us on first contact.

Tests

pytest runs the suite; the hardware touch-points are behind driver interfaces so almost everything runs against the simulator. Anything that claims to work on this site has additionally been run on a real Pi — see Status.

This site

The docs live in site/ in the same repo, built with Astro Starlight. Every page has an Edit page link at the bottom. To run it locally:

cd site && npm install && npm run dev