The sky begins
with a glance.
Universum, one step at a time. Free books, guides and tools to turn curiosity into discovery.
An initiative by Steve Cimolino · For curious minds, families and enthusiasts. Introduction to the project and books →
Coming soon in the sky.
A selection of events with approximate visibility for the displayed location. Meteor peaks are approximate; see the calendar for details and sources.
Beyond the 110 Messier objects.
Browse all 7,840 NGC numbers, filter by type or constellation and find entries that can be located in the planetarium.
Explore the NGC catalogue →
Your sky, in motion.
5,044 stars, the constellations, planets and Moon: choose your location, explore the sky and move through the night.
Our planet,
at your fingertips.
Rotate the globe, browse 242 countries and territories, view populations with their reference years and measure a straight-line distance.
What will you discover tonight?
Choose your location, time and equipment. Find suggested targets, their viewing windows and where to look, then prepare your observation.
Find my targets →What if you changed the system’s rules?
Change an orbit, vary the star’s mass and discover Kepler’s laws through an interactive experiment linked to volume III.
Observer’s dashboard
Today’s Moon, solar times, twilight and calendar highlights gathered in a dedicated tool. Choose your location and find useful information before heading out to observe.
Open my dashboard →Three ways to begin.
A question. A discovery. A first experiment.
Understand the sky
Discover the collection and the free guide to creating your own Solar System trail.
Open the library →02 / ExploreExplore the Messier catalogue
110 photographs and fact sheets to recognise objects, choose your targets and prepare your observations.
Open the catalogue →03 / ExperimentPrepare your equipment
Understand your telescope, calculate your camera’s field of view or create a Solar System trail.
Discover the tools →
The Solar System,
on the scale of your steps.
A free book, a web kit and an example project in Kirchberg to help you imagine your educational trail.
Create a Solar System trail →Four paths to discovery.
Volume 1 · Free editionObserver le ciel
ISBN : 978-99987-432-1-2
Volume 2 · Free editionExplore the sky
ISBN : 978-99987-432-2-9
Volume 3 · Free editionComprendre l’astrophysique
ISBN : 978-99987-432-7-4
Special edition · Free PDFCreate your solar system trail
The three astronomy volumes and the Solar System trail guide are available to read and download as PDFs free of charge.
The Moon, within sight.
Understand its phases, explore 100 lunar features and track your observing challenge.
Explore the Moon →NASA/Goddard/Arizona State University · LRO
Phases and calendar →
Find your way among the stars.
The 88 constellations, their guide stars and associated Messier objects, gathered in an illustrated atlas.
Open the atlas →Chart: IAU / Sky & Telescope · CC BY 4.0
One observation, one record.
Record your sessions, the equipment used and the details you saw. Find your targets, then export your log to keep a copy.
Start my log →Free, with no account · Saved in your browser · JSON and CSV export
Books and discoveries continue online.
The Solar System and Messier catalogues, constellation atlas, Moon section, evening suggestions, planner, journal and calculators are available. The Earth atlas is available as a first release: a globe, a world map and fact sheets for 242 countries and territories. Its limits are explained on its page.
Discover Steve’s passion for astronomy →From stars to orbits.
HIP Catalogue
The planetarium’s 5,044 stars: constellation, distance, temperature and size compared with the Sun.
Explore →Atlas of our Solar System
Explore planetary positions, animate orbits and approach the Earth–Moon neighbourhood.
Explore →Telescope catalogue
Choose a model, compare its properties and use it in the eyepiece view.
Explore →Finding Universum useful?
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