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Tonight

About AstroGlade

AstroGlade is a local-first web app for amateur astronomers and astrophotographers. It brings together night-sky weather, astronomical darkness, moon phase, and practical hints (planets, ISS passes, dew risk, and more) so you can decide when to observe and what to expect at your location.

The app runs in your browser as a progressive web app (PWA): you can install it on a phone or desktop, and the interface can work offline once cached, while fresh forecasts need a network connection.

Scores and timelines are heuristic planning aids, not guarantees — always use your own judgement and local safety when travelling to a dark site.

Credits

Made by

AstroGlade is built by Chris Spencer (astroglade.com).

Beta testers

Nina Spencer and Melody Spencer.

Data and services

  • Open-Meteo — weather forecasts and place search (your browser talks to this app’s server; the server requests Open-Meteo).
  • CelesTrak — two-line element (TLE) sets for satellite passes (for example the ISS).
  • Where The ISS At — live ISS position, altitude, and speed on the Space tab (fetched via this app’s server with a short cache).
  • international-space-station-APIs — who is on the ISS vs other stations for the Space tab card (via this app’s server). Open Notify is used only as a fallback.

Open-source libraries

  • SunCalc (MIT) — sun and moon position, twilight, and moon phase.
  • Astronomy Engine — planets, rise and set times, and related sky calculations.
  • satellite.js — orbit propagation from TLE data for pass predictions.

Design

Privacy

Last updated: April 2026

What AstroGlade Stores On Your Device

Saved observing locations, theme, and other settings are kept in browser storage on this device only (for example localStorage). They are not sent to an AstroGlade “account” because the app does not use logins or user accounts.

What Leaves Your Device

When you refresh or search, the app sends requests to https://app.astroglade.com — the same origin that served this page. That backend may call third-party services for weather forecasts, geocoding, or satellite orbit data, using coordinates or place names you asked for. Those providers process data under their own policies (for example Open-Meteo for weather). AstroGlade does not add advertising trackers in the app shell described here.

Caching

A service worker may cache app files (HTML, scripts, styles, icons) so the shell loads faster and can work offline. It does not replace your control over saved locations — clearing site data in the browser removes local storage.

Your Choices

You can clear saved data from Settings in the app, or remove site data in your browser settings. Using AstroGlade does not require an email address or profile.

People Behind AstroGlade

Chris Spencer

Chris is a member of Sherwood Observatory, where telescopes meet tea breaks and cloudy nights still count as “field testing.” He’s the Dark Sky Ambassador for Sherwood Observatory and a member of the International Dark-Sky Association (IDA) — a polite way of saying he’ll happily bend your ear about protecting the night: less glare for wildlife, darker skies for everyone, and the simple joy of seeing the Milky Way without driving halfway across a continent. If AstroGlade nudges you toward a clearer forecast, that’s partly his fault (in a good way).

Nina Spencer

Nina is Chris’s other half — and also a Sherwood Observatory member and volunteer, so the family telescope budget is officially a team sport. She’s the unofficial travel advisory: if there’s a dark corner of the map worth a road trip, she’s already cross-checked campsites, motorhome stopping areas, petrol stops, and whether the horizon is actually dark or just “dark for a car park.” Her superpower is finding places where the sky still feels big — then gently reminding everyone to bring a jumper, because “cold” was not in the brochure.

Melody Spencer

Melody is also on team Sherwood Observatory — same stars, different superpowers. She keeps the human side of stargazing in check: patience when the forecast lies, enthusiasm when it doesn’t, and an undisputed expertise in donuts (research field: glazed vs. filled, repeat trials welcome). Official title: tester, morale officer, and occasional “did you remember to pack snacks?” consultant.

Clear local cache?

This will remove saved observing places, theme and other preferences, and cached app files (the offline shell) from this device.

You cannot undo this. You will need to add locations again, and the page will reload.

Delete this place?

Remove from your saved places. This cannot be undone.

Sharing QR Code

Night Observing