Your moons
Each moon is a real birthday. Tap one for the details.
Or make it a present
Free
A picture of your moons to post or send.
$5
A two-page keepsake — the poster with their name on it, your own milestones marked on the years they happened, and a second page telling the story of every single moon. Ready to print and give.
One payment, no account. Both pages, in A4 and US Letter, downloaded straight away. Card or Apple Pay. If you do not love it, email me and I will refund you — you can keep the file.
About the moons
They are real
Every phase here is computed from the positions of the sun and moon using the standard astronomical series in Jean Meeus's Astronomical Algorithms — not picked from a set of stock pictures.
I check the result against the US Naval Observatory's published phase times. Across forty of their reference events between 1920 and 2099, the largest disagreement is 0.03°. The shaded part of each moon encloses exactly the fraction of the disc that was genuinely lit.
The 19-year echo
235 lunar months come to almost exactly 19 years. Astronomers call it the Metonic cycle, and it means the moon on your 19th birthday looks nearly the same as the moon on the day you were born — then again at 38, and 57.
Across 355 sample birthdates the phase came back within 3.6 percentage points on average. You can see it in your own grid.
Printing it
The Ink style is built for a home printer: light paper, not much ink. Print at 100% (not "fit to page"), and leave the margins alone — every home printer has an edge it physically cannot reach.
The file is drawn as shapes rather than pixels, so a print shop can take it up to A1 without it going soft.
What I keep
Not your birthday. No accounts, no cookies, no advertising trackers. Your date becomes moons inside your own browser; it only reaches my server if you buy a keepsake, and then only to draw the file.
I do count anonymous totals — how many portraits were made today, how many cards saved — with no way to tell who did what. Exactly what that means.