Tour of MRAO (Part 1): Lord's Bridge station and AMI Large Array
All trips at this location:
- Tour of MRAO (Part 1): Lord's Bridge station and AMI Large Array
- Tour of MRAO (Part 2): HERA, MERLIN, AMI Small Array, COAST and SKA
- Tour of MRAO (Part 3): 4C Array, Flora & Fauna, and One-Mile Telescope
- Tour of MRAO (Part 4): One-Mile Telescope Control Room
Perhaps best known for the discovery of the first pulsar, by Jocelyn Bell Burnell, the Mullard Radio Astronomy Observatory (MRAO) is located on the outskirts of Cambridge, located on the site of a former WWII munitions storage facility. The MRAO is home to many radio telescopes and antennas, with some equipment dating back to the 1950s, scattered across the several miles wide site. While most of the pre-1990s equipment is now decomissioned, there is still a lot of active work being done by the more recent arrays and telecopes.
The facility is owned by Cavendish Astrophysics, who were pioneers in this field from 1945, and opened the MRAO in 1957 (supported by Mullard Ltd. and the Science Research Council). While the many of the dishes are clearly visible from the A603, which runs right though the middle of the site, the facility is not open to the public. However, they do occasionally run guided tours, and I was fortunate enough to take part in one.
Station §
We began the tour at the old Lord’s Bridge railway station, which closed on New Year’s Eve 1967. A single length of the eastbound platform remains, with the station building and goods shed.
Outside §
Inside §
Entering the station, you pass by a little museum, with cabinet full of radio equipment dating back to at least 1949 (and possibly earlier - I didn’t manage to read it all).
Going past the little museum, there is a “lecture theatre”, which is the size of a typical classroom with about as many chairs. At the back of the lecture theatre, on the wall, is a magnificant map of GALACTIC RADIO EMISSION AT 38 Mc/s.
If I were to hazard a guess, this map comes from the paper Results of a Survey of Galactic Radiation at 38 Mc/s, published in 1957, which gives its thanks to “Mr M. Ryle” (of the former Ryle Telescope at MRAO). The diagrams in the paper are black and white, but this diagram illustrates the radio emissions much more clearly with range of blue and orange hues.
J. H. Blythe, Results of a Survey of Galactic Radiation at 38 Mc/s, Monthly Notices of the Royal Astronomical Society, Volume 117, Issue 6, December 1957, Pages 652–662, https://doi.org/10.1093/mnras/117.6.652
Among the many other interesting things shown in the lecture theatre, the following two stood out, which relate to the military history of the site: during WWII it was used as a munitions storage facility.
First is a map of the former facility, which indicates where the BOMB STORES were, and the railway tracks. While the tracks are long gone, much of the original road structure remains, as can be seen in the composite map I created.
The map used to be secret information, hence the RESTRICTED label at the top, but I’m assured that’s no longer the case.

Second is a photo of a photo of some of the old munitions: the munitions are of course no longer there, but when the MRAO was first being constructed, they did find some left over from the war that needed disposing of safely! Again, I’m assured that’s no longer the case.
Map §
To help illustrate where things are, following is a map of MRAO that I made (see this post for more details about the map).
We left the station building (Lord’s Bridge Station, in the middle near the top) and drove east along the road that follows the old east-west railway line. The road passes underneath a bridge (Haslingfield Road / Barton Road), and then we stopped at the AMI Large Array.
AMI Large Array §
Here there are eight dishes, which together form one radio telescope, the AMI Large Array.
The nearest dish was the only clean one, the others were all rather grubby. Our guide informed us that the dishes were due for cleaning, and so the cleaning process had begun, however a film crew contacted the MRAO wanting to use the AMI Large Array for their location. The film crew were keen that the dishes looked dirty, so the cleaning process was postponed until after filming was complete. I don’t know what film it was (or will be), but perhaps it’s going for post-apocalyptic vibes?
Track §
Four of the eight dishes are mounted on a railway track.
Next part §
To carry on with the tour, see here for part 2.
All trips at this location:
- Tour of MRAO (Part 1): Lord's Bridge station and AMI Large Array
- Tour of MRAO (Part 2): HERA, MERLIN, AMI Small Array, COAST and SKA
- Tour of MRAO (Part 3): 4C Array, Flora & Fauna, and One-Mile Telescope
- Tour of MRAO (Part 4): One-Mile Telescope Control Room