Arcsecond Service: Platesolver (astrometry)

This repository provides a FastAPI plate-solving service for Arcsecond, based on astrometry.net indexes and Neuromorphics Systems' astrometry Python package.

Run with Docker

docker run --rm \
  -p 127.0.0.1:8900:8900 \
  -v arcsecond_astrometry_cache:/data/astrometry \
  arcsecond-service-platesolver-astrometry:latest

Run Natively (Linux/macOS)

python -m venv .venv
source .venv/bin/activate
python -m pip install --upgrade pip
python -m pip install .
python -m arcsecond_service_platesolver.main

Run Natively (Windows)

1. Install Python 3.12+.
2. Install Microsoft C++ Build Tools (Desktop development with C++).
3. Install Rust (rustup), because astrometry may need a local native build when no matching wheel is available.
4. This project pins Windows installs to a Windows-compatible astrometry fork commit from arcsecond-io/astrometry.

py -3.12 -m venv .venv
.venv\Scripts\Activate.ps1
python -m pip install --upgrade pip
python -m pip install .
python -m arcsecond_service_platesolver.main

Configuration

• ASTROMETRY_CACHE_DIR: explicit cache directory path (highest priority).
• ASTROMETRY_DATA_ROOT: root directory used to create astrometry_cache under it.
• HOST: bind host (default 0.0.0.0).
• PORT: bind port (default 8900).
• LOG_LEVEL: Uvicorn log level (default info).

Default cache path behavior:

• If ASTROMETRY_CACHE_DIR is set, it is used directly.
• On Windows, defaults to %LOCALAPPDATA%\Arcsecond\astrometry_cache (or %APPDATA% fallback).
• On Unix-like systems, prefers /data/astrometry_cache when writable, otherwise falls back to $XDG_CACHE_HOME/arcsecond/astrometry_cache or ~/.cache/arcsecond/astrometry_cache.
• If the selected location is not writable, falls back to the OS temp directory.