Last updated: 30 October 2026
In short: you can use Asteria without an account. If you create one, it holds your name and email address, the equipment you save and the locations you save to My locations. Your current observing location is used to calculate the sky and to fetch the weather and sky brightness for that place; it is not linked to your account or kept by us unless you save it. If you become a supporter, our reseller Paddle handles the payment; we keep only your membership details. We use Google Analytics to understand how Asteria is used. We never sell your data.
Asteria (asteria.waddensky.com) is made by Waddensky, the controller for the personal data described here.
Company details and questions about privacy: use the contact form on www.waddensky.com.
When you create an account we store your name (if you give one), your email address, an account ID and how you sign in (Google or email and password). If you sign in with Google, Google shares your name and email address with us; we receive no password and no other Google data. Passwords are handled by Firebase Authentication and never reach us.
While you are signed in, your account also holds your equipment: the telescopes, eyepieces, barlows and focal reducers you add (brand, model, your own name for them and their optical figures), the field-of-view combinations you make of them, and when each was added, changed or deleted. Which fields of view are shown on the chart is not stored in your account. When you sign out, Asteria removes your equipment from that browser; it stays in your account and comes back when you sign in again.
It also holds the locations you save to My locations: the name you give each place, its coordinates, and the elevation, country, time zone and sky brightness Asteria knew for it when you saved it, plus when each was added, changed or deleted. A saved location can be your home, so only save places you are comfortable keeping in your account. As with equipment, signing out removes them from that browser; they come back when you sign in again.
We use this only to provide your account: to sign you in, to send account emails (email verification, password reset) and to keep your equipment and saved locations safe and available on all your devices (and, as Asteria grows, observing lists). The legal basis is the performance of our agreement with you (art. 6(1)(b) GDPR).
Accounts run on Google Firebase (Firebase Authentication and Cloud Firestore, a Google Cloud service; the database is located in the EU). Google acts as our processor and may process account data outside the EU under the EU–US Data Privacy Framework and standard contractual clauses. We keep your account until you delete it. You can delete it yourself at any time in Asteria (menu → your account → Delete account); this removes your account and everything stored with it immediately. The equipment and saved locations on the device you delete it from stay in that browser only.
Asteria needs a location to show the sky as you see it. It is set in one of these ways:
Your current location is stored on your device, not in your account (unless you save it to My locations while signed in, see section 1). To show weather and sky brightness, Asteria sends the coordinates to our own server (Google Cloud Functions in Belgium), which asks Open-Meteo (weather) and darkskysites.com (sky brightness) on your behalf — those services receive the coordinates, not your IP address. To save requests our server caches the answers by area (weather for 1 hour, sky brightness for 7 days), without any link to you. When you search for a place, the text you type is forwarded the same way to Open-Meteo.
The visibility map is an image from the Google Maps Static API: your browser requests it directly from Google, with the observing location as the map centre.
The legal basis is our legitimate interest in providing the features you use (art. 6(1)(f) GDPR); a location you enter yourself is processed to provide the service you ask for.
When you open a sky image or an object description, your browser loads it from the CDS hips2fits service (Strasbourg astronomical Data Centre) or from Wikipedia. These requests name the sky object, not you; like any website, those services see your IP address.
We use Google Analytics 4 to count visits and see which features are used, so we can improve
Asteria. Google Analytics places cookies (_ga, _ga_*) and collects
information such as the pages you view, the type of device and browser, and your approximate
region. Google Analytics does not store IP addresses. Google processes this data as our
processor and may do so outside the EU under the EU–US Data Privacy Framework. Google Analytics
keeps event data for 2 months and user data for 14 months.
The legal basis is our legitimate interest in understanding how Asteria is used, so we can improve it (art. 6(1)(f) GDPR). You can object at any time: block cookies for this site in your browser settings, or install Google's Google Analytics opt-out browser add-on.
Like any website, our web host records technical request data (such as IP address, time and requested page) in server logs, to keep the site running and secure. Asteria's fonts load from Google Fonts, so your browser contacts Google's servers for them.
A supporter membership is sold to you by our online reseller Paddle (Paddle.com Market Ltd, United Kingdom), the merchant of record. Paddle's checkout opens inside Asteria, but it is loaded from Paddle's servers only when you start a payment, and what you enter there (your email address, billing country and postcode, and payment details) goes to Paddle, not to us. Paddle processes that data as an independent controller, under its own privacy policy, and sends your receipts and invoices. We never see your card or bank details.
To give your account its supporter benefits, we keep with your account: your tier and the periods you paid for, the yearly amount, whether the membership renews, the date, amount and status of each payment, the country of your billing address, and the customer and membership IDs Paddle gives us. We receive these from Paddle when you pay, renew, change or stop your membership. This record lives on our server (Cloud Firestore, in the EU) and is not readable from the app; your benefits reach the app through your sign-in. The legal basis is the performance of our agreement with you (art. 6(1)(b) GDPR).
Deleting your account cancels a running membership at Paddle and deletes this record immediately. Paddle keeps its own records of your payments, as the law requires for bookkeeping and tax.
Asteria keeps the following in your browser's storage. It stays on your device; clearing your browser's site data for Asteria removes it.
| What | Why |
|---|---|
| Your last observing location and how it was set | To open Asteria where you left off |
| Your equipment (telescopes, eyepieces, fields of view), and which account it belongs to when you are signed in | To draw fields of view on the chart, also offline |
| Your saved locations (My locations), and which account they belong to when you are signed in | To switch between your observing places, also offline |
| Settings (chart layers, night mode, brightness) | To remember your preferences |
| Weather, sky brightness and space data; downloaded sky images and Wikipedia texts | Cached copies, so Asteria works faster and offline |
| Your sign-in session (only with an account) | To keep you signed in (stored by Firebase Authentication) |
Asteria also stores its own app files so it works offline as an installed app.
We do not sell or rent your data. We share data only with the service providers named above, and only for the purposes described. Supporter payments go directly to Paddle, as described in section 6.
Under the GDPR you have the right to access the personal data we hold about you, to have it corrected or deleted, to restrict or object to its processing, to receive it in a portable form, and to withdraw consent at any time. You can delete your account yourself in Asteria; for anything else, use the contact form on www.waddensky.com. We respond within one month.
If you believe we handle your data incorrectly, you can complain to the Dutch Data Protection Authority, the Autoriteit Persoonsgegevens.
We update this policy when Asteria changes how it handles personal data. The date at the top shows the latest version.