One idea.
One experiment.

Telescope catalogue

Choose a model, compare its properties and use it in the eyepiece view.

Atlas of our Solar System

Explore planetary positions, animate orbits and approach the Earth–Moon neighbourhood.

HIP Catalogue

The planetarium’s 5,044 stars: constellation, distance, temperature and size compared with the Sun.

The NGC catalogue

7,840 numbers, 8,373 entries, filters, fact sheets and locating objects in the planetarium.

The planetarium

Explore the sky by location and time: stars, constellations, planets and Messier markers.

Earth · The retro atlas

Globe, world map, countries and territories, dated population figures and distances between reference points.

Doppler effect

Compare lines at rest and in motion. Zoom in on a line and explore a fictional periodic signal.

Stellar colours

Temperature, continuous spectrum, Wien peak and UV–visible–IR distribution: explore a blackbody’s light.

Orbit simulator

One star, one planet and Kepler’s laws. Explore the orbit’s shape, speeds and period.

What can I see tonight?

Targets suited to your location, time and equipment, with viewing windows and directions.

Observer’s dashboard

Find the lunar phase, solar times and daily guides for your location.

My evening under the stars

Location, date, target: follow its altitude and find the hours of astronomical night.

My telescope

Magnification, exit pupil and estimated field of view: find the key values for your telescope–eyepiece combination.

My camera's field of view

Calculate the field covered by your sensor and your camera’s pixel scale for your focal length.

My Solar System trail

Choose a scale and give Solar System distances a tangible dimension.

Keep a record

Save your sessions, find your targets and take your notes with you as JSON or CSV.

Phases and calendar

Choose a date and time zone to find the illuminated fraction and upcoming quarters.