Moon Calendar for ChatGPT and Claude
Ask your assistant about the Moon in UK time: tonight’s phase, the next full Moon and its name, a month of phases, moonrise at your place, the eclipses the UK will see, dark-sky nights, spring and neap tide dates, the Moon’s zodiac sign and whether the new crescent can be seen. Answers come from the same calculations as this website.
What it does
The app returns the Moon’s phase, how much is lit, its age and distance for now or any date and time from 1900 to 2100, the dates and UK times of full, new and quarter Moons with each full Moon’s name and supermoon, blue Moon, micromoon and black Moon flags, a month grid of daily phases, moonrise, highest point, moonset and height for 24 UK places, upcoming solar and lunar eclipses with what the UK, or one place, sees of each, the nights of a month with a dark sky or a Moon photography window, spring and neap tide dates, the Moon’s sign and the new crescent Moon’s sighting verdicts. Results link to the matching pages here, with your date, place or year filled in where the page takes them: the Moon tonight, the phase calculator, the full Moon dates, the Moon calendar, moonrise and moonset, the eclipses, the dark sky calendar, the tide dates, the Moon sign calculator and Moon sighting in the UK.
Connect it
Add a custom connector in ChatGPT or Claude with the address below. The app is public and needs no authentication: there is no account, sign-in or key, and it is read-only.
https://mooncalendar.co.uk/api/mcp
Tools
The app has 8 tools, all read-only.
get_moon – Moon on a date
Returns the Moon's phase, percent lit, lunar age, distance from Earth and waxing or waning direction right now, at 12:00 UK time on a date, or at a UK clock time on a date. Also returns whether it is a full Moon, the next full and new Moon, and at a UK place that date's moonrise, highest point and moonset, the Moon's height and compass bearing, and whether it is above the horizon after dark. Times are UK time, GMT or BST.
Inputs
date(string, optional): UK calendar date as YYYY-MM-DD, from 1900 to 2100. Without it and without a time, or with today's date alone, the result describes the Moon right now; any other date alone gives the Moon at 12:00 UK time.time(string, optional): UK clock time as HH:MM on a 24-hour clock. The result describes the Moon at that time on the date, or on today's date without one.place(string, optional): One of 24 UK places for moonrise, highest point, moonset, height and visibility, such as London, Edinburgh, Cardiff, Belfast, Leeds or Lerwick. London without it.
Returns The Moon's phase, how much of it is lit, its age since the new Moon, its distance from Earth and whether it is waxing or waning, a yes or no for a full Moon, the next full Moon (with its name and whether it is a supermoon) and the next new Moon, and at the chosen place the moonrise, highest point and moonset with the compass direction of the rise and set, the Moon's height and bearing, and whether it is above the horizon after dark. With no date it is the Moon right now; with a date it is the Moon at 12:00 UK time on that date, as on the calendar's date finder; with a time it is the Moon at that UK clock time, as on the phase calculator.
find_moon_events – Moon phase dates
Returns the dates and UK times of upcoming full, new, first quarter and last quarter Moons, with each full Moon's traditional name, its distance, and supermoon, blue Moon, micromoon and black Moon flags. Special Moons can be listed on their own.
Inputs
phase(any, full, new, first-quarter, last-quarter, optional): Phase to list: full, new, first-quarter, last-quarter, or any for all four in date order. Any without it.special(none, supermoon, blue, black, micromoon, optional): Lists only supermoons, blue Moons, micromoons (full Moons) or black Moons (the second new Moon of a month), so it fixes the phase. None, ordinary phases, without it.from(string, optional): First UK date to include, as YYYY-MM-DD. Without it the list starts right now.to(string, optional): Last UK date to include, as YYYY-MM-DD. Without it the list covers about two years from the start, or up to 2100 for a special Moon.count(integer 1 to 24, optional): Maximum number of events, from 1 to 24. 6 without it.
Returns A date-ordered list of full, new, first quarter and last quarter Moons with the exact UK time of each, the full Moon's traditional name (Wolf Moon, Cold Moon and so on), its distance from Earth and flags for a supermoon, blue Moon, micromoon and black Moon. A special Moon can be listed on its own: supermoons, blue Moons, micromoons or black Moons.
get_moon_calendar – Moon calendar for a month
Returns every day of one UK calendar month with its Moon phase and percent lit at 12:00 UK time, plus the exact UK times of that month's new, first quarter, full and last quarter Moons.
Inputs
year(integer 1900 to 2100, optional): Calendar year from 1900 to 2100. The current UK year without it.month(integer 1 to 12, optional): Calendar month from 1 to 12. The current UK month without it.
Returns All the days of the month with the Moon's phase and percent lit at 12:00 UK time, and the exact UK times of the month's new, first quarter, full and last quarter Moons, with links to the month page and its printable calendar.
list_eclipses – Eclipses seen from the UK
Returns upcoming solar and lunar eclipses in date order with the UK peak time, the kind of eclipse and what the UK sees of it, including London contact times, coverage or totality where the Sun or Moon is above the horizon. With a place, each eclipse also shows that place's start, maximum and end, the share of the Sun covered or the Moon's height.
Inputs
from(string, optional): First UK date to include, as YYYY-MM-DD. Without it the list starts right now.count(integer 1 to 10, optional): Maximum number of eclipses, from 1 to 10. 5 without it.type(any, solar, lunar, optional): Solar, lunar, or any for both. Any without it.visibleFromUk(boolean, optional): True lists only eclipses that at least one UK place can see; false adds eclipses seen elsewhere. True without it.place(string, optional): One of 24 UK places. Each eclipse then shows what that place sees, such as London, Edinburgh, Cardiff, Belfast, Leeds or Lerwick.
Returns Upcoming solar and lunar eclipses in date order with the peak time in the UK, the kind of eclipse and what the UK sees of it: London contact times, how much of the Sun is covered, or whether the Moon is above the horizon during totality. With a place, each eclipse also shows when it starts, peaks and ends there and how much of the Sun is covered or how high the Moon is.
plan_dark_skies – Dark-sky and Moon photography nights
Returns the nights of one UK month with a dark-sky window, when the Sun is more than 18° below the horizon and the Moon is down, at one of 24 UK places, with each night's window times, hours and Moon phase. For photography it returns each night's Moon window, when the Moon is at least 5° up while the Sun is more than 6° below the horizon. Times are UK time, GMT or BST.
Inputs
place(string, optional): One of 24 UK places, such as London, Edinburgh, Cardiff, Belfast, Leeds or Lerwick. London without it.month(string, optional): UK calendar month as YYYY-MM, from 1900-01 to 2100-12. The current UK month without it.purpose(dark, photo, optional): Dark lists nights with a moonless dark-sky window; photo lists nights with a Moon photography window. Dark without it.
Returns The nights of a month at a UK place with a dark-sky window (the Sun more than 18 degrees below the horizon and the Moon down) or, for photography, a Moon window (the Moon at least 5 degrees up while the Sun is more than 6 degrees below the horizon), each with its window times, hours and the Moon's phase.
get_tides – Spring and neap tide dates
Returns the dates and UK times of spring tides (new and full Moons) and neap tides (first and last quarter Moons) from the Moon's phases, in date order, with the next spring tide and next neap tide first and perigean spring tides flagged. These are tide dates, not times or heights for a port.
Inputs
year(integer 1900 to 2100, optional): Calendar year from 1900 to 2100 whose tide dates are listed. Without it the list starts at from, or right now, and runs on into the next year.from(string, optional): First UK date to include, as YYYY-MM-DD. Without it the list starts right now, or at the start of the year given.count(integer 1 to 24, optional): Maximum number of tide dates, from 1 to 24. 8 without it.
Returns Spring tide dates (new and full Moons) and neap tide dates (first and last quarter Moons) in UK time from the Moon's phases, the next spring tide and the next neap tide first, with perigean spring tides flagged. They are tide dates, not times or heights for a port.
get_moon_sign – Moon sign
Returns the Moon's zodiac sign right now, on a UK date or at a UK date and time, tropical or Lahiri sidereal, with the degree into the sign, the next sign change and the website's one-line meaning of the sign. With a date alone it returns every sign the Moon is in that day.
Inputs
date(string, optional): UK calendar date as YYYY-MM-DD, from 1900 to 2100. Without a date and a time the result is the Moon's sign right now.time(string, optional): UK clock time as HH:MM on a 24-hour clock. With a date it gives the exact sign at that time; without a date it is today.zodiac(tropical, sidereal, optional): Tropical zodiac, which starts at the March equinox, or Lahiri sidereal. Tropical without it.
Returns The Moon's zodiac sign right now, on a date or at a date and time, tropical or Lahiri sidereal, with the degree into the sign, the next sign change and the website's one-line meaning of the sign. With a date but no time it lists every sign the Moon is in that day.
check_crescent_visibility – New crescent Moon sighting
Returns the first three evenings after a new Moon with a crescent sighting verdict (likely, difficult or not visible) for each of 24 UK places, with sunset, moonset, Moon age, height and best viewing time. It covers the latest new Moon until its third evening is over, then the next one.
Inputs
date(string, optional): UK calendar date as YYYY-MM-DD, from 1900 to 2100, near a new Moon. The result is the window the website would show on that date. The current window without it.
Returns The first three evenings after a new Moon, each with a likely, difficult or not visible verdict for the new crescent at 24 UK places, and per place the sunset, moonset, Moon age, height and best viewing time.
What you see in the chat
Results appear as cards with a picture of the Moon’s phase, eight at first and eight more each time you ask for more. Open a day or a Moon event to see the Moon on that date, step to the previous or next day, choose another UK place, or open the page on this site. Open a night, a tide date or a crescent evening for its details. A month appears as a calendar grid. The view follows the light or dark setting of ChatGPT or Claude and can open full screen.
Try asking
- What does the Moon look like tonight?
- When is the next full Moon, and is it a supermoon?
- What time does the Moon rise in Edinburgh on 12 December?
- Show me the Moon phase calendar for December 2026.
- Which eclipses can I see from the UK?
- Which nights in December are dark enough for stargazing near Edinburgh?
- When are the next spring tides?
- What sign is the Moon in today?
- Can I see the new crescent Moon in the UK this month?
The data
Phases, rise and set times and eclipse circumstances are calculated with the open-source Astronomy Engine library, as on the rest of this site. All times are UK time: GMT in winter and BST in summer. A date’s phase is the Moon at 12:00 UK time on that date. A supermoon is a full Moon within 361,400 km of Earth, a convention rather than an official definition, a blue Moon is the second full Moon in a UK calendar month and a black Moon is the second new Moon in one. Tide dates follow the Moon’s phases; high water at a port comes a day or two later and differs at every harbour, so the app gives no port times or heights. The Moon sign is the website’s zodiac calculation with its one-line meaning, not a prediction. The lunar eclipse catalogue was checked against NASA’s; the solar eclipse list has not been checked against an independent source. The app covers the UK only and gives no astrology predictions, weather or visibility forecasts. Nothing you ask is stored: read the privacy page and the terms.
Support
Questions, corrections or problems with the app: abishop1933@gmail.com. Include what you asked, the date and place you chose and what the app answered. For the rest of the site see about Moon Calendar.