Does the moon phase change depending on where you are?
No. The phase is set by the angle between the sun, the earth and the moon, and that angle is the same for everyone. A full moon is full at one instant worldwide. What is local is the clock time you write that instant down as, and the moonrise and moonset times, which shift with your latitude and longitude. That is why this site asks for a city.
Why does the moon sometimes not rise at all on a given day?
The moon rises roughly 50 minutes later each day, so about once a month a rise or a set skips a calendar day entirely. It is not a mistake — the times here are computed from the moon's real position, so a missing entry is a genuinely missing event.
How accurate is this?
Phase and illumination are within a fraction of a percent. Rise and set times are typically within a minute or two of the published almanac figures for the same city. The calculation uses the principal terms of the standard lunar and solar series, applies the parallax correction for an observer on the surface rather than at the centre of the earth, and allows for atmospheric refraction at the horizon. Every figure was checked against reference values before this site went live.
Why is the moon in the widget a drawing rather than a photograph?
Because a drawing can be correct. The terminator — the line between light and shadow — is computed for the exact moment you load the page, so the shape you see is the shape the moon is actually making tonight, not a photograph of some other night that happened to look similar.
Do you store anything about me?
No. There is no account, no analytics on your movements around the web, and no third-party tracker. The only thing kept is your chosen city and colour theme, saved in your own browser so the page looks the same next time. Clear your browser data and it is gone.
Can I put this on my own website?
Yes, and free — there are five widgets on the embed page, all served over HTTPS with no iframe and no tracking.
Who makes this?
It is built and paid for by the team at Harmony Elements, a small UK shop. The site carries no advertising and sells nothing; it exists because we wanted a moon calendar we trusted and could not find one.