The MarkII Correlator

The old NRAO Mark II VLBI correlator has been stored in the old scientific office building at the VLA since we stopped using it. I prevented it from being thrown away then and am called on to do so again as they now want to remodel the building. On 2004 March 24, I went to the VLA to see what condition the correlator is in. It is not completely whole - some panels and parts are missing, but most is still there, along with two VCR drives. The photos show what I saw, after digging it out of a pile of other cast off gear that surrounded it. Note that only 3 of the 4 racks in these photos is the correlator. The shrink wrapped one is a Mark III control rack.

After inspecting the correlator, I dropped in on the group trying to get EVLA first fringes. It turned out that the big moment had happened shortly before I got there. I got the photo below of Barry Clark, Ken Sowinski, Mike Revnell, and Jim Jackson just as they were deciding how to announce the fringes.

Click on the image for a screen size version. The "full size" version is larger.

Full size A MarkII VCR (and a lot of dust) Full size The MarkII correlator output tape drive. Much of the front paneling for this rack is missing. There are two small panels on top of the lower device - they are shown in another photo below.
Full size The devices lower on the output tape rack. I forget what this is. Full size The MarkIII control rack.
Full size The main MarkII correlator rack. This is the heart of the beast, and the part still in best condition. Full size Another of the same.
Full size The bottom units of the main rack. Full size The top units of the rack.
Full size The rack with the keyboard has been stripped. This is all that is left in it. There was an FPS120B (actually 2) nearby. Did we have one of them in it. I thougth what we had was much older. Full size A longer view of that rack.
Full size The other MarkII VCR. Full size The panels that were flat on the earlier picture of the rack with the output tape drive.
Full size Side view of the control and correltor racks with the second VCR on top. Full size The 4 racks (including the MarkIII side by side after some rearranging. This is how we left it.
Full size The FPS120B array processor that was nearby. Full size Two boxes of MarkII correlator documentation.
Full size Victory! First EVLA fringes have just been obtained. (I just stumbled on the occasion, I was not involved. Full size The VLA from the access road.