The science behind
your moon phase print.
How we recreate the exact lunar appearance for your chosen date, time and location, using the same astronomical data trusted by observatories worldwide.
A personalised moon phase print is a precise visual representation of the Moon as it appeared at a specific moment that matters to you. Using real astronomical calculations, we render the correct phase, illumination percentage, and orientation for your exact date, time, and location. No approximations. No generic imagery.
The geometry of Earth, Sun and Moon.
The Moon's phase is determined by its position relative to Earth and the Sun. As the Moon orbits Earth over approximately 29.5 days, we observe different portions of its sunlit hemisphere.
When the Moon lies between Earth and the Sun, the near side receives no direct sunlight — that's a new moon. When Earth lies between the Sun and Moon, we see the fully illuminated face — that's a full moon. Everything in between is a fraction of that lit half.
Phase is universal, orientation is local.
Everyone on Earth sees the same phase percentage at any given moment. But your location determines how the Moon appears oriented in your sky.
A waning crescent that opens to the left in London opens to the right in Sydney. When you provide your location, we calculate the precise parallactic angle to match how the Moon appeared from your perspective — not just what fraction was lit, but how that lit portion was tilted in your sky.
The Moon doesn't reset at midnight.
The Moon's illumination changes continuously — not just day by day, but hour by hour. A print generated for 9:00 PM will show a subtly different phase than one for 6:00 AM the same day.
And there's more: as the Moon travels across the sky from moonrise to transit to moonset, it appears to rotate by up to 90 degrees or more depending on your latitude. The crescent that tilts one way at dusk may appear nearly upright at midnight.
For moments that happened at a specific time — a birth at 3:47 AM, a proposal at sunset, a midnight celebration — this precision captures the Moon exactly as it hung in your sky at that instant. Many off-the-shelf moon prints only account for the date, missing both the illumination shift and this rotational change that makes each moment truly unique.
Every parameter, computed precisely.
Our calculations are anchored to high-precision astronomical algorithms, including ephemeris data of the type used by NASA and professional observatories. For each print we compute:
Lunar phase
Exact illumination fraction and phase value, calculated from Sun–Moon–Earth geometry at your moment.
Precise time
Hour and minute of your moment — affects illumination and the Moon's position in the sky.
Libration
The Moon's subtle wobble that reveals slightly different surface features over time. Yes, the Moon really does shift — by a few degrees in each direction.
Position angle
The orientation of the Moon's rotational axis relative to celestial north — the spin component of how it sits in the sky.
Bright limb angle
Determines which edge of the Moon is illuminated, derived from the Sun's position relative to the Moon's centre.
Parallactic angle
Observer-specific rotation based on your latitude, longitude and local time — this is what makes the print feel like your sky.
These calculations use algorithms derived from Jean Meeus's Astronomical Algorithms and the IAU lunar pole model, ensuring accuracy that holds up to scientific scrutiny.
From numbers to real lunar surface.
Once we've computed the precise astronomical parameters, we render the Moon using detailed lunar surface imagery. The render includes displacement mapping for crater depth and normal mapping for fine surface texture.
The lighting is positioned mathematically based on the computed bright limb angle, creating an accurate representation of how sunlight fell across the lunar surface on your date — at your time, from your place.
One cycle, eight named phases.
The Moon's cycle is divided into eight named phases, each representing a specific range of illumination as the Moon progresses through its orbit.
New Moon
0% illuminated
Waxing Crescent
1–49% growing
First Quarter
50% illuminated
Waxing Gibbous
51–99% growing
Full Moon
100% illuminated
Waning Gibbous
99–51% shrinking
Last Quarter
50% illuminated
Waning Crescent
49–1% shrinking
Each phase carries its own character. A full moon signifies culmination and clarity; a new moon represents fresh beginnings. When you select your date, you're capturing the specific moment in the lunar cycle that corresponds to your memory.
Why scientific accuracy matters more than decoration.
Your moon phase print is a genuine representation of the cosmos at a specific moment. The phase, orientation and lighting are calculated rather than approximated. When you look at your print, you're seeing the Moon exactly as it appeared overhead at that hour, from the place where it happened.
Date-only approximation.
Most personalised moon prints on the market calculate the phase based solely on the date. But the Moon doesn't reset at midnight — it moves continuously through its orbit, changing appearance hour by hour. A print that ignores the time of day can be off by a meaningful amount, especially near phase transitions.
Full time precision.
We factor in the exact time of your moment, your location's parallactic angle, and the Moon's libration — so the phase, the tilt and the visible surface features all match what was overhead. This is the difference between an illustration and a portrait of the sky.
Ready to capture your moon?
Pick the night, the place, the time — we'll render the Moon exactly as it appeared overhead.
