NASA’s Astronomy Picture of the Day features a view of Venus showing an extended crescent with bright tips known as the “horns,” according to the agency’s post. The image highlights that Venus, like the Moon, shows phases when seen from Earth. The post says the view was captured when Venus was almost directly between the Sun and Earth, an alignment that occurs about every year and a half.
NASA explained that, unlike a dark new Moon, Venus remains visible in this geometry because its backlit atmosphere refracts and scatters sunlight. That bending and scattering produce a glowing arc that can stretch beyond 180 degrees, creating the appearance of bright horns at the tips of the crescent. The agency noted that the effect becomes apparent near this alignment, which is similar to the monthly configuration that creates a new Moon.
The post said the crescent can be seen with a small telescope or binoculars during twilight. It added that people with exceptionally acute eyesight may be able to spot the thin crescent without optical aid. The explanation emphasized that Venus’ phases are a lesser known fact compared with the familiar phases of the Moon.
NASA also linked the visual effect to Venus’ changes in brightness. The post said ancient Babylonian astronomers may have been the first to study how Venus’ brightness varies, which is related to its phases. It added that many other cultures recorded similar observations, including references in the oldest surviving Maya book.
The featured image is credited to Thierry Legault. The Astronomy Picture of the Day includes a brief explanation written by a professional astronomer. NASA listed the service as a collaboration of the Astrophysics Science Division at NASA’s Goddard Space Flight Center, NASA Science Activation, and Michigan Technological University. The agency did not provide additional technical details about the observation in the post.