Welcome to the Jupiter Company Observatory

The Jupiter Company is a small amateur astronomy group based in Paris.
Our members are interested in long-term celestial observation,
stellar variations and historical astronomical references.

We occasionally publish notes about unusual stellar behavior, sky observations and notable events.

Observational Astronomy

Observation remains the core activity of the group.

Members regularly conduct sessions dedicated to both near-sky and deep-sky observation. These sessions may include planetary monitoring, lunar surface observation, double star measurements and the tracking of variable stars.

Deep-sky observation is also an important part of our work. Using amateur telescopes and optical instruments, members attempt to observe nebulae, open clusters, globular clusters and distant galaxies whenever atmospheric conditions allow it.

Although the observatory operates with modest equipment, we believe that careful observation, patience and methodical note-taking remain at the heart of amateur astronomy.

Instruments and optics

Many members of the Jupiter Company share a particular fascination for astronomical instruments.

Discussions within the group often revolve around optical design, telescope construction and the evolution of observing tools. Our members use a variety of instruments ranging from small refractors and Newtonian reflectors to larger amateur Dobsonian telescopes.

Beyond the use of modern equipment, we also maintain an interest in the historical instruments that shaped observational astronomy: early refractors, meridian circles, transit telescopes and other devices once used to measure the movement of celestial bodies across the sky.

Understanding the tools used by astronomers throughout history helps us better appreciate the observations recorded in older archives.

Historical Astronomy

A significant part of the Jupiter Company’s curiosity lies in the history of astronomy.

The group maintains a growing archive of notes related to historical coordinate systems, astronomical measurement techniques and the development of early observatories. Particular attention is given to the evolution of meridian systems and the ways in which astronomers attempted to establish universal references for mapping the sky.

Before the adoption of the Greenwich meridian as the international standard, several reference lines were used by astronomers in different parts of Europe. One of these historical meridians crossed Paris and played an important role in early astronomical measurements.

Many of our archival notes and discussions explore how these systems were used, how observations were recorded and how astronomers attempted to standardize their understanding of celestial movement.

Archival Work

The Jupiter Company also collects and digitizes various observational notes, historical references and fragments of older astronomical documentation.

These archives are not intended to be exhaustive or academic in nature. Rather, they represent the collective curiosity of amateur observers attempting to preserve fragments of astronomical history that might otherwise be forgotten.

Whenever possible, members try to reproduce historical observation methods and compare them with modern techniques in order to better understand how earlier astronomers perceived the sky.

Philosophy

The Jupiter Company believes that amateur astronomy remains one of the most accessible and rewarding ways to explore the universe.

A clear sky, a patient observer and a simple optical instrument are often enough to rediscover the same celestial wonders that fascinated astronomers centuries ago.

Whether observing a bright planet, tracking a faint nebula or studying the methods of historical observers, the group continues to approach the sky with the same mixture of curiosity, patience and fascination that has always driven astronomy forward.

 

Some of our historical observation notes are currently being catalogued and digitized.