The Arecibo Observatory in Puerto Rico has joined forces with telescopes located in North America, South America, Europe and Africa to create the observing power of a radio telescope 6,800 miles (nearly 11,000 kilometres) in diameter. This collaboration is called the Express Production Real-time e-VLBI Service (EXPReS) project, and on May 22nd, the system went “live” with all antennae observing the same part of the sky. This is an historic project where international collaboration has resulted in the most powerful radio telescope system available to date…
May 22nd heralded the first live demonstration of the EXPReS project that used radio telescopes from four continents. e-VLBI stands for “electronic Very Long Baseline Interferometery” and the system has the huge benefit of taking real-time observations. Data from the EXPReS project is transmitted to the central signal processor at the Joint Institute for VLBI in Europe (JIVE) in Holland, where speeds of data-streaming have exceeded Arecibo’s previous record four times over. Apart from being an acronym fest, the e-VLBI, EXPReS, JIVE collaboration will observe the cosmos with a resolution of 100 times better than the worlds most advanced optical telescopes.
So how can a single radio telescope dish with a diameter of 6,800 miles be simulated if the project has telescopes scattered around the planet? This is where the clever technique called Very Long Baseline Interferometery (VLBI) comes in. If you have multiple telescopes observing the same radio source in the cosmos simultaneously (and using very precise atomic clocks as a guide), the distance (or base-line) between observatories will simulate the effect of using a telescope with a diameter of that distance. The resolution of the observation is improved when the interferometer has several observatories working as one. Traditionally, the radio signal received at each antenna was recorded on a magnetic tape and then shipped to a central processing facility. The results of a campaign usually took weeks to be compiled. By using the e-VLBI system, recording data at the telescope site can be bypassed and transmitted real-time to the central processing facility along with the other telescopes observing the same source. Results are now available in a matter of hours – essential rapid processing when fast astronomical processes (such as supernovae) are in progress.
“These results are very significant for the advance of radio astronomy. It shows not only that telescopes of the future can be developed in worldwide collaboration, but that they can also be operated as truly global instruments.” – Huib Jan van Langevelde, JIVE Director.
The EXPReS project is funded by the European Commission and aims to connect 16 of the world’s most sensitive radio observatories. In the middle of this collaboration is the JIVE processor so real-time data processing can help astronomers achieve very quick results and react to transient radio sources.