About CosmicByMe
The story of the day you were born, told through space and Saju.
CosmicByMe started from a simple question: what did the universe actually look like on the day you were born? Not a generic zodiac horoscope, not a generic birthday card — the real sky, the real coordinates, and the real Five-Element reading tied to your own birth date and time.
What the site does
You enter your birth date and time (and optionally your location), and CosmicByMe generates a single downloadable card that combines three things:
- A real NASA photo — the actual Astronomy Picture of the Day published on your birth date, pulled live from NASA's public APOD archive.
- Your birth-sky star map — a real, astronomically accurate star chart centered on your zodiac constellation, rendered with real star and constellation-line data (not a stock illustration).
- Your Five-Element (Ohaeng) reading — your Day Master element, calculated from your birth date and time using traditional Saju (Four Pillars) methodology. This runs on real Manseryeok (perpetual calendar) logic — actual solar-term boundaries and lunar-calendar conversion, not a simplified date lookup — paired with a short reflective passage.
Everything is composited into one shareable, Instagram-story-sized image you can download directly — nothing is stored on our servers, and there's nothing to sign up for.
How to use it
- Enter your birth date and time on the homepage. Both are required — the date sets your Western zodiac sign, and the exact hour and minute are what the Saju calculation actually needs to determine your Day Master element, since the traditional two-hour time blocks (12 per day) can put two people born hours apart into different elements.
- Add your location, if you want to. Tap GPS to use your current position, or type coordinates in manually. This is optional — if you skip it, the card falls back to Seoul's coordinates so the star map still renders correctly. Location only affects which stars are visible and the card's accent color theme; it's never stored anywhere.
- Add a short signature, if you want one. A name or short message that appears on the card itself — also optional.
- Hit Generate. The card lifts off its placeholder, spins while your NASA photo, star map, and Saju passage are put together, and settles into its final design after a few seconds.
- Regenerate once, if you'd like a different result. With the same inputs, the button becomes "Regenerate" and produces a new NASA photo pairing and a different Saju passage (your calculated Day Master element itself stays the same, since that's a fixed calculation, not a random draw). You get one regenerate per set of inputs — changing any field unlocks it again.
- Click Download or Share to keep the finished card. Download saves it as a PNG; Share opens your device's native share sheet (on supported browsers) so you can send it straight to Messages, KakaoTalk, Instagram, or wherever you'd post it, without a manual save-and-upload step.
Why we built it
Most "cosmic birthday" tools either fake the star map or skip the astronomy entirely and just slap a zodiac icon on a template. We wanted something that actually holds up — real coordinates, a real sky, and a real (if playful) Saju reading, wrapped in a design that feels like a keepsake rather than a throwaway meme.
Who's behind this
CosmicByMe is an independent, single-developer project. It isn't affiliated with NASA, though it does use NASA's public APOD API under their open data terms. If you want to get in touch, see our Contact page.
Read more
We also write about astronomy, Saju/Five-Element concepts, and the ideas behind the site on the CosmicByMe blog.