Venus observed in crescent phase by astronomers

Astronomers have recorded images of Venus appearing in a crescent phase, similar to the Moon, as observed from Earth on September 15, 2026. During this period, approximately 30% of the planet's reflective surface was oriented toward terrestrial telescopes.

This visual phenomenon is caused by Venus's orbital position between the Earth and the Sun. As the planet follows its elliptical path, the angle of sunlight hitting its dense atmosphere changes, causing observers on Earth to see different fractions of its illuminated side. This effect occurs regularly as the planet approaches inferior conjunction.

Historically, these phases were first documented by Galileo Galilei in 1610. His observations of Venus's changing appearance provided the physical evidence necessary to support the heliocentric model proposed by Nicolaus Copernicus, fundamentally altering the course of classical astronomy.