PHD2 Log Viewer — Web Edition

A browser-based viewer and analyzer for PHD2 guide logs. Open a log file and explore RA/Dec error traces, guide pulses, mass/SNR, calibration runs, periodic-error analysis, polar-alignment estimates, and more — all entirely in your browser. Your logs never leave your machine; everything is parsed and rendered client-side.

▶ Live app: https://bvalente22.github.io/phd2-log-viewer-web/

This is a TypeScript/React port of agalasso/phdlogview (the C++ / wxWidgets desktop tool). The parser and statistics math are direct ports of the original logparser.cpp / LogViewFrame.cpp; the UI was rebuilt with React + Plotly.

What it does

• Guiding sections — RA/Dec error traces over time, guide pulses, star mass/SNR, and a scatter view with the error ellipse and RMS readouts.
• Calibration sections — 2D scatter of the calibration step positions plus a pointing-context dashboard (pier side, hour angle, declination, altitude, etc.).
• Periodic-error analysis — FFT periodogram and drift charts to find your mount's periodic error and worm period, matching the desktop PHDLogView output.
• Polar-alignment estimate — per-section and whole-log polar-alignment error with a bullseye readout.
• Estimated imaging impact — projects guide RMS + seeing into an estimated star shape, to gauge how guiding will affect your subs.
• Annotations & recents — name your logs, add notes, and re-open recent files.
• Six languages — English, Español, Deutsch, Français, Italiano, and 简体中文, switchable from the 🌐 picker. (PHD2 jargon — RA, Dec, RMS, SNR, etc. — intentionally stays in English everywhere.)

Using it

1. Open the live app (or run it locally — see below).
2. Drag a PHD2 guide log onto the drop zone, or click to browse for one. These are the PHD2_GuideLog_*.txt files PHD2 writes to its log directory. You can also drop the matching PHD2_DebugLog_*.txt alongside it to enable the in-app debug-log viewer.
3. Pick a section from the sidebar to inspect it. Open the Analysis panel for periodic-error / periodogram tools.

Chart interactions

• Scroll wheel — zoom the X axis around the cursor.
• Left-drag — pan X and zoom Y (drag up = zoom in).
• Right-drag — pan Y and zoom X.
• Shift + drag — include a time range; Ctrl/Cmd + drag — exclude one.
• Right-click — context menu (include/exclude all, exclude dithers/settling, reset section, reset zoom).

Running it locally

The app lives under web/. You need Node.js (18+).

cd web
npm install        # install dependencies
npm run dev        # http://localhost:5173
npm run build      # production bundle into web/dist/
npm test           # vitest unit + golden tests

The build is a fully static bundle (web/dist/), so any static host works (GitHub Pages, Vercel, Netlify, nginx, …). See web/README.md for the full developer guide — stack details, project layout, the translation workflow, versioning, and deployment options.

Repository layout

web/        the application (React + TypeScript + Vite) — see web/README.md
docs/       design docs, specs, and portable how-tos
LICENSE     GPLv3 (same as upstream PHD2 Log Viewer)

License

GPLv3, the same license as the upstream PHD2 Log Viewer. See LICENSE.