Privacy, on this page.
Covers asteryn.app only
Last updated October 20, 2026
The email address
Besides the server log below, this page collects one thing, and only if you choose to give it: an email address, when you join the waitlist. It goes to Buttondown, the service that sends the mail, and it is used to tell you when your invite is ready and to send launch news and early-access offers, a few times a month at most.
Buttondown can record whether an email is opened or a link in it is clicked. You can unsubscribe at any time using the link in any email. If we change how we use your email, we will update the date above and tell you by email before doing so. Your address is not sold, rented, or shared with advertisers or data brokers.
If you reached this page from one of our posts or a shared birthday link, the signup also notes the source (TikTok, Instagram, YouTube, Reddit or a birthday share), so we can tell which links bring people here. The label is carried in the web addresses of this site's own pages and goes to Buttondown only with an email you choose to submit. The birthday is never attached to your signup.
The birthday
The birthday you type into the calculator is read by code running inside your own browser. Calculating your Sun or Moon does not send your birthday, birth time or time zone to us or to anyone else. None of them is stored or attached to your email address. The page does tell our server that a result was shown (see The server log, below).
If you choose to share, your card and its link include your birthday's month and day, never your birth year, time or time zone. If you added a birth time, the card and the message sent with it can show your Moon sign, but the time itself is never on the card, in the message or in the link. The image is made in your browser. Saving it downloads it to your device; sharing sends it to the app or person you choose. Opening the link sends its month and day to this website as part of the URL, which may appear in normal hosting logs and browser history. The link shows a birthday preview; the person opening it can enter their own full birthday for their own result.
The server log
This page sets no cookies and uses no ad trackers. When the calculator shows you a Sun or Moon, the page tells our server that one was shown. That message does not include your birthday or anything else you typed. Google, which hosts this site, keeps these messages for us in a standard server log, along with any visit to our short links (asteryn.app/tt, /yt and /ig).
Each entry in the log holds the web address requested, the time, your IP address and the city and country it points to, your browser and device type, and the page or app you came from. Entries are deleted after 30 days. We use the log only to count link visits and results shown each day, and never connect it to your email address.
Asking us anything
To ask what we hold, or to have it deleted, email jeremy.asteryn@gmail.com.
What this notice does not cover
Asteryn is in a closed, US-only alpha. This notice describes this public page and nothing else. A full privacy policy covering the app will be published before Asteryn opens to everyone.