By Jonathan Amos
Science reporter, BBC News
Europe's new Herschel space observatory has provided a demonstration of its capability with a first image of the iconic Whirlpool Galaxy.
The billion-euro telescope opened its "eyes" to the cosmos last Sunday when a command was given to lift a protective hatch covering the instrument bay.
Herschel spied the galaxy, also known as M51, with its Photoconductor Array Camera and Spectrometer (PACS).
Scientists stress Herschel is still in its commissioning phase.
They need to learn how best to operate the facility.
Nonetheless, the very first test observation suggests the optical performance of Herschel will more than meet the design expectations.
Scientists connected with the mission said they were "ecstatic" with the results.
Albrecht Poglitsch, the lead scientist on PACS, told the BBC "nobody in their right mind would ever have predicted such a quality at the very first attempt".
HERSCHEL SPACE TELESCOPE
The observatory is tuned to see the Universe in the far-infrared
Its 3.5m diameter mirror is the largest ever flown in space
Herschel can probe clouds of gas and dust to see stars being born
It will investigate how galaxies have evolved through time
The mission will end when its helium refrigerant boils off
The European Space Agency (Esa) mission was launched from Earth on 14 May.
The observatory's quest is to study how stars and galaxies form, and how they evolve through cosmic time.
Herschel is sensitive to light at long wavelengths - in the far-infrared and sub-millimetre range.
PACS covers the shorter end of the spectrum; the SPIRE (Spectral and Photometric Imaging Receiver) instrument looks at the longer end.
Whereas PACS got its opportunity to look out into the Universe immediately after the hatch opening on Sunday, SPIRE was not scheduled to make its first observation until Tuesday.
Its check-out targets were likely to include an object in our Solar System as well as something far-distant.
Left: The best view of M51 taken by Nasa's much smaller Spitzer space telescope and its Multiband Imaging Photometer
Right: The bigger Herschel telescope's image is sharper. The European observatory reveals new structures in M51
Dr Poglitsch described his feelings on getting the first imagery down from Herschel.
"It certainly was a moment to remember," he told BBC News.
"We were anxiously watching the progress bar on the computer. When, finally, the first image showed up on the screen it was truly amazing - nobody in their right mind would ever have predicted such a quality at the very first attempt.
"So, it was a mix of disbelief and exaltation, with the latter one gradually prevailing as all three 'colours' rolled in one after the other.
"The nice colour picture, of course, took days of more advanced processing of the data in the three individual bands and then quite some optimisation at the colour image level to visualize the information it carries.
"So, when we had reached that level - three days after the initial arrival of the data - everybody on the team was absolutely enthusiastic about what we had achieved.
"I would say that it was a once-in-a-lifetime experience."
Dr Poglitsch is affiliated to the Max-Planck-Institut für extraterrestrische Physik, Garching.
The PACS team celebrates the first image. Albrecht Poglitsch is standing far right