A faint object changes the planetary census

Cook and Green recorded the transit from Tahiti during an international observing campaign.

European expedition members observed from an island with its own navigational and celestial knowledge traditions.

Cook and Green's drawings helped document the event and the difficulty of timing its edge.

Observations from Tahiti were compared with observations elsewhere to estimate the scale of the solar system.

He recorded a small object in Gemini, at first thinking it might be a comet.

The first modern discovery of a planet began with this observation.

The precise dated sighting enabled other astronomers to establish the object's orbit.

Titania was one of the first two moons of Uranus discovered on this date.

Observations of a faint point near the planet added a new satellite to the known solar system.

Titania's detection showed that the recently identified planet was orbited by moons.