A supermoon lit up the sky as stargazers enjoyed the Perseid meteor shower - one of the year's most dramatic lunar events.
The moon appeared 14% bigger and 30% brighter than normal as it reached the point in its orbit closest to the Earth, known as "perigee".
The spectacle came two days before the meteor shower reaches its peak.
Given a dark, clear sky in a normal year, it is common to see more than 100 of the meteors an hour during the second week in August.
Dr Bill Cooke, from NASA's Meteoroid Environment Office, said the luminous supermoon risked drowning out the meteor shower.
He said: "Lunar glare wipes out the black-velvety backdrop required to see faint meteors, and sharply reduces counts."
Dr Cooke added that the Perseids were also "rich in fireballs as bright as Jupiter or Venus" that would remain visible despite the moon's glare.
A study conducted by his team since 2008 has shown the Perseids to be the undisputed "fireball champion" of meteor showers.
"We see more fireballs from Swift-Tuttle than any other parent comet," said Dr Cooke.
Every 133 years, comet Swift-Tuttle swings through the inner Solar System leaving behind a trail of dust.
When the Earth passes through, the dust cloud particles hit the atmosphere at 140,000m/hr and burn up in streaking flashes of light, creating the spectacle known as the Perseids.
The meteors will be visible until Wednesday, with activity peaking tomorrow.
An unusually bright full "supermoon" was also seen on 12 July, and is due to appear again on 9 September.
Supermoons occur relatively frequently, usually every 13 months and 18 days, but are not always noticed because of clouds or poor weather.