Privacy policy
1. Controller
André Riethmüller
Email: kontakt@skygrade.de
2. Collection and processing of data
When you visit this website, the hosting provider automatically records technical information. This includes in particular the IP address, date and time of access, browser type, operating system and other technically necessary connection data. This data is used solely to ensure secure and trouble-free operation of the website.
To calculate the SkyGrade score, users can enter a location and other details required for the calculation (e.g. date and Bortle class).
The entered location is converted into geographic coordinates (latitude and longitude) and transmitted to the external services listed below to perform the calculations. If coordinates are entered directly as GPS values, they are also transmitted to Nominatim (OpenStreetMap) to determine the associated place name.
The light pollution estimate (Bortle class) is performed exclusively locally on the server using an existing map data set. No data is transmitted to external services for this.
To improve performance, SkyGrade stores already computed results in a database (cache). Only the input data required for the calculation (location, date and Bortle class) and the results computed from them are stored.
No personal data is stored, no user accounts are created, and the stored records are not linked to the IP address of visitors.
3. External services
SkyGrade uses the following external services to calculate the results. With each new calculation, coordinate data (latitude and longitude) is transmitted to these services:
-
Nominatim (OpenStreetMap) – conversion of place names or postal codes into coordinates, and vice versa from GPS coordinates into place names
Privacy policy of the OpenStreetMap Foundation -
Open-Meteo – weather data
Terms & privacy of Open-Meteo -
7Timer – astronomical seeing data
7Timer documentation -
OpenRouteService (HeiGIT gGmbH, Heidelberg) – calculating the car driving time between your starting location and the observing sites (only when using “Where tonight?”). Only coordinates are transmitted; the request is made server-side, so your IP address is not sent to OpenRouteService.
OpenRouteService privacy policy -
Map display (Leaflet, CARTO, unpkg) – On some pages (e.g. “Where tonight?” and the location map) you can optionally show a map. Only after your explicit click are map tiles loaded from CARTO/OpenStreetMap and the Leaflet library from unpkg directly in your browser; in the process your IP address is transmitted to these services.
CARTO privacy policy - Sky images (CDS, Strasbourg) – The Astrophoto Planner shows a sky view for each object. SkyGrade fetches this image server-side from the Centre de Données astronomiques de Strasbourg (CDS) and stores it on its own server; while you view the page your IP address is not transmitted to CDS. Only after you explicitly click “Explore interactively” are the interactive view (Aladin Lite) and its sky tiles loaded directly from CDS in your browser; in the process your IP address is transmitted to CDS.
Centre de Données astronomiques de Strasbourg
The data is transmitted solely to perform the calculation requested by the user.
4. Reviews
SkyGrade offers visitors the option to voluntarily leave a review with a freely chosen nickname and an optional comment.
The submitted information is processed solely for the purpose of publishing the review. Publication takes place only after a manual check by the operator.
Please do not use your real name as a nickname and do not enter any personal or sensitive data in the comment.
Protection against spam and misuse
To protect the review function, SkyGrade uses exclusively privacy-friendly technical measures. These include in particular:
- an automated honeypot method to detect spam bots,
- a plausibility check of the submission time,
- and a browser-side block on further review submissions via local browser storage (
localStorage).
The localStorage used serves solely to prevent multiple review submissions within the same
browser for a limited period. No personal data is stored or transmitted to the server in the process.
Publication
After a successful check, only the following information is published:
- the chosen nickname,
- the star rating,
- the voluntarily entered comment,
- and the publication date.
The review is not linked to any specific person.
5. Data protection
SkyGrade places great value on data-minimizing and transparent operation. The website was deliberately designed to process as little data as possible.
Cookies and local browser storage
SkyGrade does not use any cookies for regular visitors. No tracking, analytics or advertising cookies are used. A cookie banner is therefore not required to use the website.
For individual technical functions, SkyGrade uses the local storage (localStorage) and
session storage (sessionStorage) provided by the browser. These are not cookies. The
information stored there remains solely in the browser of the user and serves only technical purposes,
for example anonymous visitor counting, preventing multiple review submissions or pre-filling the
most recently entered location. It is not analyzed for advertising, analytics or profiling purposes.
No user profiles
SkyGrade does not create user profiles and does not pass on any personal data to third parties for advertising or marketing purposes.
Our goal is to provide a fast, privacy-friendly and transparent platform for astrophotography and visual astronomy.
6. Your rights
Under the General Data Protection Regulation (GDPR) you have the right to:
- access to the data stored about you (Art. 15 GDPR)
- rectification of inaccurate data (Art. 16 GDPR)
- erasure of personal data (Art. 17 GDPR)
- restriction of processing (Art. 18 GDPR)
- data portability (Art. 20 GDPR)
- objection to the processing of personal data (Art. 21 GDPR)
In addition, you have the right to lodge a complaint with a competent data protection supervisory authority if you believe that the processing of your personal data violates applicable data protection law.