Sun and Moon Help Documentation

A complete guide to the sunrise, sunset and moon calculator, from choosing a place to the next eclipse.

Last Updated: November 3, 2026

1. Getting Started

1.1 What you need

• A modern browser (Chrome, Edge, Firefox, Safari or Opera) with JavaScript enabled, on a computer, tablet or phone
• Site data allowed for zerodataupload.com, so your place and settings are kept between visits

1.2 How the page is laid out

At the top left is the place, with its time zone and coordinates; click it to change the place. On the right are the date with the arrows and Today, the link button, Settings and Help. The five tabs below choose the view: Today, Sun, Moon, Calendars and Sky events. Each view is made of cards; on a wide screen some stand side by side.

1.3 The first time

The page opens on a city in your device's time zone (Ambernath for India) and today's date. Choose your own place once; the page remembers it and opens there next time.

2. Choosing a Place

2.1 From the list

Click the place at the top left. The window lists your recent places and the 30 cities nearest the current one. Type in the search box to find any of the about 200 cities by name, or a country by its first letters; press Enter to take the first match.

2.2 By coordinates

1. Type the latitude and longitude into the search box, separated by a comma (for example 19.2, 73.18), and choose the line that appears; the time zone of the nearest listed city is used.
2. Or open Enter coordinates and time zone, type the latitude (north plus, south minus) and longitude (east plus, west minus), a name, and choose the time zone; then Use this place.

A map app shows the coordinates of any spot: press and hold it. This site does not ask your browser for your location, so there is no Use my location button.

3. Choosing a Date

Use the arrows beside the date for the day before and after, click the date to pick one from the calendar, or Today to come back. Any date from 1 January 1800 to 31 December 2199 works. Clicking a day in a list, the 30-day table, the moon calendar or the year in daylight also opens it, and Look up a day in history under Sky events offers a few famous days.

4. Today and the Sky Dial

4.1 The dial

The ring is the whole day, midnight at the bottom and noon at the top, coloured by the light: night, astronomical and nautical twilight, blue hour, golden hour and daylight. The grey arc inside shows when the Moon is above the horizon. The hand points at the moment shown in the middle; drag it, or focus the dial and use the arrow keys, to see any moment. When you look at today, the hand follows the clock until you move it; Back to now returns it.

4.2 The headline and the facts

For today the headline says what comes next, for example how long until sunset, and the line under it the time after that and the day length. For other days it gives the date, the day length and the Moon. The facts give sunrise and sunset with the direction the Sun is in, solar noon with the Sun's height, the day length and how it changed since the day before, first and last light, and moonrise and moonset.

4.3 The day, hour by hour

Every event of the day in order: dawn and dusk twilights, blue and golden hours, sunrise and sunset, solar noon, moonrise, the Moon at its highest and moonset. For today a line marks the present moment and the events already past are greyed.

5. The Sun View

• Height of the Sun and Moon through the day: a chart of their height in degrees, with the twilight bands. Drag across it, or focus it and use the arrow keys; the readout above gives the time, the Sun and Moon's height and direction, and the shadow of an object.
• Where to look: the sky seen from above, north at the top, the centre straight overhead and the circle the horizon. The solid lines are the Sun's and Moon's paths today, the faint arcs the Sun's path on the longest and shortest days. Beside it, the directions of sunrise, sunset, moonrise and moonset.
• Shadow length: enter the height of an object and its unit to see its shadow at the chosen moment and where it points.

6. The Next 30 Days and the Year

The table gives, for 30 days from the selected one, first light, sunrise, sunset, last light, the day length, the evening golden hour, moonrise, moonset and the Moon's phase. Download CSV saves a spreadsheet with every twilight and golden hour time as well; Print prints the Sun view. The year in daylight colours every day of the year by the Sun's height; move across it to read a day and click to open it.

7. The Moon View

• The picture: the Moon as lit at that moment. As seen from here turns it the way it looks from your place; North up shows it as in most photographs.
• The facts: how much is lit and whether it is waxing or waning, its age, moonrise and moonset, its height and direction, distance, apparent size, and its zodiac sign (tropical and Vedic). The bar shows the distance between the closest and farthest possible, with the next closest and farthest days.
• Next phases: the next new moon, first quarter, full moon and last quarter.
• Moon calendar: any month, day by day, with the phases, supermoons, eclipses and blue moons marked. The arrows change the month; click a day to open it.
• Full moons: every full moon of the selected year with its traditional name, its Hindu name and festival, its time and distance, and marks for supermoons, micromoons and eclipses.

8. The Hindu Panchang

Under Calendars, for sunrise at the chosen place, with the Lahiri ayanamsa:

• Day (vara), tithi and paksha, nakshatra, yoga and karana, each with the time it ends and the ones that follow before the next sunrise (a time on the next day carries its weekday)
• Month in the amanta or purnimanta system (choose under Settings), with an adhika month marked
• Samvat: the Vikram and Shaka years, counted from Chaitra
• Sun sign and Moon sign (sidereal), and the ayanamsa used

Coming tithis lists the next Purnima and Amavasya, both Ekadashis, Sankashti and Vinayaka Chaturthi, both Pradosh days and the next two Sankrantis, each with the moment it begins and ends. The panchang is for reference: festival days also depend on local custom, so check your temple calendar.

9. Muhurta and Rahu Kaal

• Brahma muhurta: the two muhurtas before sunrise, one muhurta being a fifteenth of the night
• Abhijit muhurta: the eighth of the fifteen muhurtas of the day, around midday (traditionally not used on Wednesdays)
• Rahu kaal, Yamaganda and Gulika kaal: one eighth of the daytime each, which eighth depending on the weekday, as in the standard tables

Where the Sun does not rise and set on a day, these periods do not exist and the page says so.

10. The Islamic (Hijri) Date

The date follows the Umm al-Qura calendar of Saudi Arabia, from its published tables for 1 August 1924 to 16 November 2077; outside these the browser's own calculation is used, and the page says which. Because the Islamic day begins at sunset, the date after sunset is shown too; in Ramadan, the day of fasting and the time of iftar at sunset. Coming Islamic dates lists the next Islamic New Year, Ashura, Mawlid an-Nabi, Isra and Miraj, Shab-e-Barat, the start of Ramadan, Laylat al-Qadr, Eid al-Fitr, the Day of Arafah and Eid al-Adha; dates kept at night are shown on the evening before. Where months begin with a local sighting of the crescent, dates can be a day later: follow your community's announcement.

11. Eclipses

Sky events lists the solar and lunar eclipses of the next six years, up to ten. Each one says whether you can see it from your place:

• Lunar eclipses: visible when the Moon is up; partly visible when it rises or sets during the eclipse. The local times of the partial and total phases and how much of the Moon enters the Earth's dark shadow.
• Solar eclipses: how much of the Sun is covered at the greatest moment, or that it is total or a ring of fire here, and when it starts and ends, also when the Sun rises or sets during it. Never look at the Sun without certified eclipse glasses.

For eclipses not visible from your place, the page says where the central path runs.

12. Meteor Showers, Seasons and Supermoons

• Meteor showers: the eleven main showers of the year from the selected day, with the night of the peak, the rate under a perfectly dark sky, the Moon at 3 am (Dark sky, Some moonlight or Bright Moon) and how high the radiant climbs at your latitude.
• Equinoxes and solstices: the next four, with what they mean in your hemisphere.
• Supermoons: the next four full moons closer than 360,000 km.

13. Sharing and Calendar Files

The link button at the top copies an address that opens the same place, date and view on another device. It carries the place's coordinates, name and time zone, so share it only where you mean to; when the link is opened, the page takes these off its own address at once. If the browser does not allow copying, a window shows the link to select and copy. The calendar buttons beside visible eclipses and meteor showers save a calendar file (.ics) to add the event to your own calendar.

14. Settings

• Clock: the device's own choice, 12-hour or 24-hour
• Distances: kilometres and metres, or miles and feet
• Hindu month names: amanta or purnimanta
• Saved data: Forget saved place and settings

The light and dark theme follows the round button at the top right of every page of the site.

15. Keyboard Shortcuts

• [ and ] the day before and after; T today (outside a text box)
• 1 to 5 the five views; ← and → move between the tabs
• On the dial or the chart: the arrow keys move 10 minutes, Page Up and Page Down an hour, Home and End the start and end of the day
• ? the help window; Esc closes a window

16. How Accurate It Is

Sun and Moon uses standard astronomy formulas (Jean Meeus, Astronomical Algorithms). They were checked against a professional ephemeris from NASA's Jet Propulsion Laboratory for 45 places from the equator to the Arctic and every year from 1901 to 2049:

• sunrise, sunset and solar noon within a few seconds; twilight, golden and blue hour within half a minute
• moonrise and moonset within a minute; moon phases, equinoxes and solstices within a minute
• the greatest moment of an eclipse within about a minute; the share of the Sun covered within a fraction of a percent
• tithi, nakshatra, yoga and karana end times within half a minute; the Hijri date equal to the Umm al-Qura tables on every day from 1924 to 2077

The times are for a flat horizon at sea level. Hills, buildings, the height you stand at and unusual air near the horizon can move what you see by a few minutes, and far from the equator, where the Sun crosses the horizon slowly, by more.

17. What Is Remembered

Your place, up to six recent places and your settings are kept in this browser's storage on this device, so the page opens where you left it. Nothing is kept on a server. Forget saved place and settings, under Settings, removes them and leaves the rest of the site alone.

18. Troubleshooting

• My place is forgotten every time. The browser blocks site data (some private windows do). Use a normal window, or keep a shared link to your place.
• The times are an hour off. Check the time zone shown under the place; for coordinates you typed, choose the right zone under Enter coordinates and time zone.
• Sunrise looks later than the page says. Hills or buildings to the east hide the first minutes of the Sun; the page counts a flat horizon.
• A calendar file does not open. Some browsers save it to Downloads without opening it; open it from there.
• The link button does nothing. The browser may not allow copying; select the link in the window that opens and copy it yourself.

19. Support

For questions the FAQ does not answer, use the contact form and say which place and date you looked at.