e-MERLIN / VLBI National Radio Astronomy Facility

e-MERLIN status

e-MERLIN Overview

e-MERLIN is a major upgrade to the MERLIN array of 5 remote telescopes operated together with telescopes at Jodrell Bank Observatory (JBO) as an aperture synthesis array. With a maximum baseline of 217 km, the angular resolution of e-MERLIN at 5 GHz is 40 mas, comparable to the Hubble Space Telescope.

The e-MERLIN upgrade is designed to increase the sensitivity of MERLIN by more than an order of magnitude using new receivers and telescope electronics together with a dedicated optical fibre network to connect each telescope at a bandwidth of 30 Gb/s to a new correlator at JBO.

The project has been funded by the University of Manchester, the North West Development Agency, the Science and Technology Facilities Council, the University of Cambridge and Liverpool John Moores University. Operational funding will be provided by STFC and the University of Manchester.

The new 4-8 GHz receivers are already installed on the telescopes and performing well. They are routinely used for observations of methanol and excited OH. Massive deployable lenses have been installed at three telescopes, so that all telescopes can now rapidly change between observing bands. The dedicated optical fibre network, involving 90km of new fibre cable installed along the roads and to connect to 600km of 'dark fibre' leased from major UK networks is in place. All the new analogue signal processing equipment (up-converters, phase-locked LO multipliers, down-converters) has been designed at JBO, prototyped and tested and pre-production units are being used on the first telescopes to be equipped. Digital samplers have been designed and are also being used for the first tests. The digital and optical transmission equipment has been designed by NRAO, in collaboration with JBO for e-MERLIN, EVLA and ALMA. The new correlator is being designed and built by DRAO at Penticton, Canada, and a prototype version has been installed and tested.

The project partners that have contributed to the construction of e-MERLIN are: