With its 3.5 meter diameter, Herschel is currently the largest telescope installed in space, orbiting the second Lagrange point. Its instruments, with which it can scan the universe in the infrared, extending from 60 to 670 micrometers, are undergoing their first full test in space. New images make astronomers very optimistic about the future of the mission.

Herschel was launched last May 14 and, like Planck, its destination was an orbit around the L2 Lagrange point, approximately 1.5 million kilometers from Earth. There Herschel revolves around the sun still up in the shadow of the Earth, which is required to limit the heating of its instruments, cooled to observe in the infrared and submillimetre.

It was at these wavelengths that the three instruments of Herschel can hope to bore new secrecies on the birth of the planetary systems and stars as well as the evolution of the galaxies over periods ranging up to ten billion years.

The SPIRE Herschel delivers its first images at different wavelengths in the infrared. The observed galaxy is Messier 74. Credit: ESA

On 14 June, engineers and astronomers in charge of Herschel took the first image, ahead of schedule of the mission. The choice had focused on the spiral Whirlpool Galaxy, M51, and the result was up to expectations. It was even beyond their expectations.

Researchers immediately started a preliminary test of all instruments Pacs, Hifi, especially Spire (Spectral and Photometric Imaging Receiver), specifically designed to study the areas where the stars of our Galaxy and its neighbors are formed.

Left: M66 observed by the instruments of Spitzer

Right: Image by by Spire Herschel

Instruments are still functional but to calibrate

On June 24 remarkable images of two galaxies, M66 and M74 in infrared was obtained. The tests were completed on 7 July. When compared to the images provided to similar wavelengths by the Spitzer telescope, the gain in resolution appears immediately.

Again, in spite of a still rudimentary image processing, the images are already beyond the expectations of astrophysicists. They clearly showed the regions where star formation is active, through the emission of dust in these regions.

M74 observed (left) by the instruments of Spitzer and (right) Spire Herschel. Credit: Nasa-Esa

Researchers are now employed to calibrate and test the Herschel instruments more deeply, at least until November 2009.

Then they will begin the operational phase of purely scientific observations of Herschel. The publication of preliminary results is scheduled for May 2010.