A rocket carrying a satellite space telescope has lifted off from the Uchinoura Space Centre in Japan.
Japan's third launch this year (Image: Jaxa)
The M-5 rocket blasted off at 0628 on Wednesday (2128 GMT Tuesday) after a 48-hour delay caused by heavy rain.
The Astro-F probe will use infrared wavelengths to study the heat glow of space objects hidden by clouds of cosmic dust.
European astronomers are collaborating with Japan on the 500-day mission to make a map of the Universe.
Astro-F will orbit the Earth over the North and South Poles to make its infrared and far-infrared survey of the sky.
The All Sky Survey, as it is called, will be conducted at a much higher sensitivity than the one first obtained by an infrared astronomical satellite launched in 1983.
"This is a tremendous new window on the primordial Universe," said Dr Stephen Serjeant, senior lecturer in astrophysics at the Open University in Milton Keynes, UK.
"Astro-F is expected to be one of the most important international observatories of the decade."
Astro-F will obtain new information on the birth of stars (Image: ISAS/Jaxa)
Glenn White, professor of astronomy at the Open University and the CCLRC Rutherford Appleton Laboratory, said the mission would provide a powerful new tool to learn about the birth and formation of stars and planets.
"It is going to completely revolutionise the study of galaxies in the process of formation at the edge of the Universe," he told the BBC News website.
Astro-F was the third Japanese launch this year, as the nation's space programme races to catch up with its regional rival China.
The Japanese Aerospace Exploration Agency (Jaxa) launched two H-2A rockets carrying observation satellites in January and February from the remote southern island of Tanegashima.