Artwork depicting the angular size of the Andromeda galaxy compared to the Moon. The Andromeda galaxy, at 2.5 million light years from Earth, is arguably the most distant astronomical object visible to the naked eye. However, it appears as little more than a smudge ??the eye can only really see the brightest region of the galaxy, its core. This illustration shows the full extent of the galaxy compared to the Moon for scale. The galaxy is 178 x 63 arc minutes across, while the Moon is only 30 arc minutes. If we could see the entire galaxy with our eye it would measure around six times wider than the full Moon.