Merlin stands for the Multi-Element Radio-Linked Interferometer Network,Jodrell Banks array of six observing stations that together form a powerful telescope with an effective aperture of over 217 kilometres.
At a wavelength of six centimeters MERLIN has a maximum resolution of 40 milli arc seconds, about twenty times better than can commonly be achieved by the best ground-based telescopes, and comparable to the Hubble Space Telescope. Such resolving power is equivalent to measuring the diameter of a one-pound coin from a distance of 100 kilometres.
|The base telescope is either the Lovell Telescope or the Mark II at Jodrell Bank. Then there are a cluster of two telescopes in the immediately surrounding countryside, both of which are 25 metre dishes made to the same design as the elements of the Very Large Array (VLA) of 27 radio telescopes in New Mexico. One of these is sited at Tabley and the other at Darnhall. Athird, similar 25 metre dish, stands at Knockin in Sropshire. More distant still is the 25-metre telescope at the Royal Signals and Radar Establishment at Defford, once used as part of RSRE's own interferometer, but now permanently linked into MERLIN. From 1990 MERLIN's most distant outpost, at Cambridge, has a new purpose-built telescope with a bowl 32 metres in diameter.||
The 25-metre MERLIN telescope at Darnhall in Cheshire.
The 25-metre MERLIN telescope at Defford in Worcestershire, formerly part of the Royal Signals and Radar Establishment.
|All the telescopes are being equipped with state-of-the-art radio receivers, based on technology developed by radio astronomers in Britain and the US. To reduce noise and increase sensitivity, the receivers are cooled to a temperature of 14 degrees above absolute zero.|
Apart from Defford, all the MERLIN telescopes will ultimately work at wavelengths as short as 13 millimetres, achieving a resolution of 0.01 seconds of arc.
It is a tribute to the scientists and engineers who developed MERLIN that such a collection of disparate telescopes can be harnessed together to work as a coherent unit. Only the 32-metre at Cambridge was purposely designed as an element of MERLIN.