Last updated: 23 August 2026
Who we are
Astrian is operated by Javier Linero, a sole trader based in Málaga, Spain. You can reach us at info@astrian.app.
What data we collect
We do not collect personal data. The birth data you enter into our calculators (date, time, place) is processed in real time and never stored on our servers. Once the calculation is returned to your browser, that data is discarded. The app is the exception and has its own section below: coordinates do leave the phone, and an installation identifier does travel with them.
We do not require account creation. We do not collect names, email addresses, or any identifying information through our tools.
If you choose to support us via Ko-fi, that transaction takes place on Ko-fi's platform, not on astrian.app. Ko-fi's own privacy policy applies.
If you subscribe to the newsletter, we store your email address, the language and the page you subscribed from, the exact consent text you accepted and its version, and the IP address and browser you used. The legal basis is your consent (GDPR art. 6(1)(a)); the IP address and browser are kept solely as proof of that consent, as the accountability principle requires. You can unsubscribe from the link in every email, and everything above is then deleted.
The iOS app
This policy also covers Astrian Light, our iOS app, in addition to the website.
The location permission. The app does not ask for it on launch: only when you tap the location control. If you granted it earlier, opening the app reads your position to prepare the sky where you are, without asking again. You can withdraw the permission at any time in your phone's settings: the app keeps working and you pick the place by hand.
Your exact coordinates leave the phone, and it is worth saying plainly why. Working out whether the terrain hides the Sun from you needs a horizon profile, and that profile belongs to the point where you stand, not to your district: a hundred metres away a ridge either blocks the Sun or it does not. Rounding the coordinate before sending it would produce an answer that sounds just as confident and is wrong. So it goes in full, to our server, and it is used to compute your horizon and the daylight times of that point.
What is not attached to those coordinates: no account, no name, no email address, no user profile, no tracking and no advertising. We do not know who you are, and we do not want to.
What we keep of your coordinates. In our database, the exact coordinate is not stored. All that is recorded is the 0.25° cell — about 28 km across — that the point falls into, on a work list for computing the terrain of that area; whole cities fit inside one of those cells. That said, let us be exact: today the request carries the coordinate inside the web address, and addresses are kept in our hosting provider's technical access logs for a limited time, as on any website.
An installation identifier. Each installation of the app sends our server an identifier generated by the iPhone itself, different for every app: it does not say who you are, it does not follow you across other apps, and it disappears if you delete the app. It serves one purpose: sharing out the number of requests fairly when many people use the app at once from the same place, such as a viewpoint on the day of an eclipse. The counter that uses it expires after 121 seconds, and no usage record is kept beyond that counter: after those two minutes there is no trace left that your phone asked us anything.
Which external services the app queries, with what data and for what: MET Norway, the Norwegian meteorological service, receives the coordinate rounded to a 0.1° cell — about 11 km — for the cloud forecast; Celestrak receives only the catalogue number of the space station, for its public orbit; MapLibre serves the map typefaces; and the eclipse map layers are downloaded from our own storage on Cloudflare R2. None of them receives your identifier or your exact coordinates.
The app has no accounts, no usage analytics, no advertising and no tracking of any kind, and no third-party tools for any of those three. We do not know how often you open it or what you do inside.
Cookies and tracking
On the website we use Vercel Analytics, a privacy-focused service that collects aggregated, anonymised usage data — page views, device type, and country. Vercel Analytics does not track individual users across sessions, does not build user profiles, and does not share data with advertising networks.
We do not use Google Analytics, Facebook Pixel, or any third-party tracking service. We do not use advertising cookies. Vercel may set strictly necessary technical cookies for hosting and security purposes; these cannot be disabled without breaking the site.
Third-party services
Astrian works with the following service providers:
Supabase — database, hosted in the European Union. It stores the newsletter data described above and the site's editorial content. It acts as a data processor on Astrian's behalf.
Resend — newsletter email delivery. It receives your email address so it can deliver the messages you subscribed to. It acts as a data processor.
PostHog — usage analytics, in its European Union region. It records which pages are visited and what is clicked, with no session recording and without keeping a profile between visits. It acts as a data processor.
Sentry — error reporting. When something breaks, it receives the technical detail of the failure so we can fix it. It acts as a data processor.
Vercel Inc. — hosting and analytics. Vercel operates servers in the US and EU. Vercel privacy policy.
GeoNames — geocoding. When you type a city name into a location field, that city name is sent to GeoNames to return coordinates. No personal data is transmitted.
Our astronomical calculation engine — built by Astrian and hosted in the EU via Railway. It receives only date, time, and geographic coordinates. It does not receive any identifying information.
International data transfers
Vercel operates infrastructure in the United States and the European Union. Aggregated analytics data may be processed in the US under Standard Contractual Clauses in accordance with GDPR Chapter V. No personal data is transferred, since none is collected.
Astronomical calculations are processed by our own engine, hosted on Railway in the EU region.
The providers above act as data processors on Astrian's behalf, under a processing agreement and, where they process data outside the European Union, under the European Commission's Standard Contractual Clauses.
Your rights under GDPR
As a resident of the European Economic Area, you have the following rights with respect to your personal data:
Right of access — you may ask what data we hold about you. Since we store no personal data, the answer will be: none (unless you have subscribed to our newsletter, when active).
Right to erasure — you may request deletion of your newsletter subscription at any time.
Right to object — you may object to processing at any time.
Right to lodge a complaint — you have the right to file a complaint with the Spanish data protection authority, the Agencia Española de Protección de Datos (AEPD).
To exercise any of these rights, contact us at info@astrian.app.
Children's privacy
Our services are not directed at children under 16. We do not knowingly collect data from children. If you believe a child under 16 has submitted personal data to us, please contact us at info@astrian.app and we will delete it promptly.
Changes to this policy
We may update this policy from time to time. Changes will be posted on this page with an updated date at the top. For significant changes, we will add a notice on the site.
This policy was last updated on May 11, 2026.