ESA’s Herschel space observatory has as planned exhausted its supply of liquid helium coolant forcing its optics offline. In effect, Herschel has gone blind which ends over three years of pioneering observations of the cool Universe. Herschel was Launched in May 2009 and, with a primary mirror 3.5 m across, is/was the largest, most powerful infrared telescope flown in space.
Herschel observed near-infrared and sub-millimeter wavelengths that are abundant inside star-forming nebulae and young galaxies. Running out of coolant has declared the mission officially over. In order to be sensitive to the extreme wavelengths Herschel needed to be cooled to near-absolute zero (-273 degrees Celsius or -459 F).
The space telescope was the most advanced of its kind making groundbreaking discoveries of the nature of our universe. Although Herschel has died, other observatories are geared to observe in the sane wavelengths. In Chile the ground-based ALMA array is now online and is able to access sub-millimeter wavelengths with the 747-mounted SOFIA telescope accessing near-infrared wavelengths.
So in three years how much data did Herschel collect. “Herschel has exceeded all expectations, providing us with an incredible treasure trove of data that will keep astronomers busy for many years to come,” says Prof. Alvaro Giménez, ESA’s Director of Science and Robotic Exploration.
The figures are impressive. Herschel has made over 35000 scientific observations, gathering more than 25000 hours of data from about 600 observing programmes with a further 2000 hours of calibration observations also contributing to the dataset.
“Although this is the end of Herschel observing, it is certainly not the end of the mission – there are plenty more discoveries to come,” says Dr Pilbratt.
“We will now concentrate on making our data accessible in the form of the best possible maps, spectra and various catalogues to support the work of present and future astronomers. Nevertheless we’re sad to see the end of this phase: thank you, Herschel!”
The thumbnail images below show just a snippet of views from Herschel over the last three years. Make sure you visit the official ESA Space in Images page and search for Herschel for more ‘cool’ images.
All images copyrighted to ESA/Herschel, PAC and SPIRE
The image of Andromeda (M31) is awesome, it uses both the PACS (Photodetecting Array Camera and Spectrometer) and SPIRE (Spectral and Photometric Imaging Receiver) instruments to observe at infrared wavelengths of 70 um (blue), 100 um (green) and 160 um and 250 um combined (red).
Herschel will continue communicating with its ground stations now that the helium is exhausted, during which a range of technical tests will be performed.
Finally, in May, it will be propelled into its long-term stable parking orbit around the Sun.