| A person suffering from double vision (diplopia) is well advised to consult his/her doctor because it may be an indication of some serious medical problem. For radio telescopes, however, it is a much desired property because it greatly enhances the efficiency and flexibility of the instrument. Recent observations done with EMBRACE have demonstrated that multiple vision can be efficiently realised for radio telescopes working around 1 GHz.
Last week, EMBRACE was used to do two observations near 1.4 GHz simultaneously by phasing the EMBRACE aperture array elements in such a way to form two beams on the sky at the same time. One beam was used to track a pulsar (right) while the other beam was scanning over the sky to image the neutral hydrogen along the Milky Way (left). The figure shows the results of these observations: the pulse profile of the pulsar detected and the longitude-velocity diagram of the neutral hydrogen along the Galactic plane (with the double structure indicating spiral arms of the Galaxy).
These results show the great potential of double vision for radio telescopes: multiple simultaneous observing modes (in this case recording a time series of a single source and at the same time scanning the sky to do imaging spectroscopy). They also mark the important progress which is being made at ASTRON in developing the technology for the radio telescopes of the future, in particular the Square Kilometre Array.