Apphemeride for iPhone

Explore the sky with precision.

Eclipses, planets, coordinates, twilight, the motion of the Sun and Moon — all calculated right on your iPhone, wherever your curiosity takes you.

Download on the App Store Explore the features My story

Eclipse journeys

Follow the Moon's shadow across the Earth

Find out where the next solar eclipse crosses the Earth, and preview how it will look from your destination. Apphemeride lets you plan the place, date, and time — before you book.

A family planning a solar eclipse trip while viewing the eclipse path map in Apphemeride on an iPhone.

A couple in the mountains checking an Apphemeride eclipse simulation on an iPhone during sunset.

Route set? Then simulate the eclipse for that exact spot. Everything is calculated locally on your iPhone — planning works even without an internet connection.

For nights worth carrying the telescope

See when, where, and in what form Saturn, Jupiter, or Venus appear in the night sky.

Find out when and where planetary constellations become visible from your location, and read exact coordinates in the formats of your choice. Apphemeride shows angles, movements, and rates the way you need them.

Two women setting up a telescope beside a campfire on a quiet beach under a starry mountain sky.

Everything is calculated right on the device, so observing nights succeed even without internet reception.

Which way your room faces

When can I see the Moon or Saturn from my hotel-room window?

Planning to book a hotel in a faraway country? You've already looked at how the buildings are oriented on the map, and now you want to know whether a particular celestial body is visible from your room at all — and if so, when? Apphemeride can answer that too. It lets you plan your trip, and even your room, a little better when you have such special wishes.

A person lying in a modern hotel room at night, holding an iPhone running Apphemeride and looking through the window at the Moon over the sea.

When daylight behaves differently

Understand twilight, polar day, and the Sun’s path at extreme latitudes.

Planning a trip to Scandinavia, or studying the Sun over Antarctica? Apphemeride helps you see how dark the night becomes, whether darkness arrives at all, and how high the Sun stands above the horizon.

A red-gold low Sun glowing over a blue-white Antarctic ice landscape.

The result is not a weather forecast. It is local astronomical calculation, available even when the network is not.

For students who want to check the math

Validate astronomical coordinate work with a precise reference in your pocket.

Compare ecliptic, equatorial, and horizontal perspectives. Use Apphemeride to verify calculations, inspect coordinate relationships, and build intuition while working through astronomy exercises.

University students solving astronomy coordinate exercises while a professor explains celestial planes at the board and Apphemeride is visible on an iPhone.

Do you have to calculate astronomical values yourself, say as homework for university? Here you can check your results.

For people who ask why the sky feels different

Explore how the Sun and Moon change with place, season, and hemisphere.

Why does the Moon’s first quarter look reversed in another hemisphere? Why does the Sun move differently across the sky in Argentina, Canada, Scandinavia, or South Africa? Apphemeride turns those questions into precise, local calculations.

A calm African savanna at twilight with a half moon, stars, distant trees, and peaceful wildlife silhouettes.

It is built for people who love numbers, but want the wonder to stay visible.

My story

My childhood and Apphemeride — why I made all of this

I was born with a severe visual impairment. All my life, the direction of the Sun, the time of day, and the season have been deeply important to me for finding my bearings. Even as a small child, I didn't orient myself by buildings or paths. I memorized which way the Sun faces, at which time, in which season. Light and shadow were always my compass. I could already read a clock when I was just 4 years old.

Even as a first-grader, something fascinated me: on a cold day in November, the Moon at 5 p.m. stood almost in the same spot in the sky as the Sun on a summer morning at 10 a.m. In summer, by contrast, I was often sad that the full Moon hung so low. I loved looking at it. Even as a child, I wondered: why is that?

I often daydreamed about what our lives would be like if the day were governed not by the Sun but by the Moon. Imagine the Moon telling us when it's morning and when it's noon. Then perhaps our ancestors would have built moon clocks instead of sundials.

When I was seven, I always set the world time on my CASIO watch by the Moon. Simply because it made me happy. I dreamed of a clock that calculates the date and time from the position of the Moon. That was the very first thing I later built into Apphemeride. It's a small, unassuming feature of Apphemeride — but to me the most important one. It's the “Moon” readout on the moon map, together with the date and time.

For my birthday, my grandma often gave me a calendar listing the times when the Moon rises and sets.

A child sits in a stroller, holding a small round clock and pointing toward the low evening Sun by a lake on a warm evening.

A family celebrates a boy's birthday by the lake in the evening as he unwraps a moon calendar, while a cake with eight candles and a modern, moonlit moon clock stand on the table.

Later, I travelled the world. That's when I noticed that the Sun moves across the sky completely differently in other countries. In the Southern Hemisphere it even looks as if it's going backwards. I deliberately planned my first trip to Singapore so that I would experience the one day when the Sun stood exactly overhead. I'll never forget being the only person outside — everyone else had fled indoors from the intense heat. Something else surprised me even more: in Singapore, the Moon was suddenly upside down.

I simply wanted an app that supports my special sense of orientation — a sense I developed because of my visual impairment. And I wanted to share my great love of astronomy, which has been with me since childhood. I hope that you, too, enjoy Apphemeride. That would make me very happy.

A young man sits with his girlfriend on an airplane, holding an iPhone and a compass and watching, with delight, the low Sun over the polar region.

Take precise astronomy with you.

Apphemeride is built for planning, observing, studying, and asking better questions about the sky - directly on your iPhone.

Download on the App Store