Even specialist museums don't know everything. On this page we pose our own queries. We would value your help in identifying and dating these items. Maybe you have a story about using such an item, or a photograph tucked away. Maybe you know how it works or could even supply us with a copy of the instructions! Any results will feed into our detailed cataloguing exercise.
Question posted January 2008
Can anyone tell us about this military collimator for calibrating binoculars? It is marked with the military arrow and the words 'Collimator Rhomboid / TH' . An accompanying technical drawing as well as the label inside the lid of its wooden crate (pictured) identifies it as a Mark IV model... but from when and by whom?
Question posted April 2006
We are seeking historic catalogues/price lists from Dollond & Co and/or Aitchison & Co to help us answer the increasing number of enquiries we receive on these famous optical companies. Could you donate any? If you are not willing to give the originals away would you perhaps be willing to copy them for us? Contact the museum curator if you can help.
Question posted February 2006 (updated April 2006 and January 2008)
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OK, we now know what this is. Our questions are a little more precise: Is anything missing from this military Infra-red viewer? Should the 'nozzle' have a cap? Why are there screw threads at both ends?
Looking through the 'eyepiece' you see a grid pattern within. It had been suggested that it may be a form of range finder but, thanks to readers of this page, we now know it is a Spy Tabby Infrared Monocular MK1 (T) night vision scope ...in which case what was it doing in a hospital?
Could this wartime instrument have been combined with another medical instrument for peaceful research purposes in post-war Bristol?
We now think it dates from circa 1942 and was one of the earliest forms of military night vision scope. It could pick up signals from a special RG lamp. Employed by the Combined Operations Pilotage Parties (COPPs) 1942-1945 and the Special Operations Executive (SOE), it was top secret state-of-the-art technology. Such scopes were also used extensively in Normandy during the D-Day landings, presumably once ashore since infra-red does not travel well through water vapour. The primary infra-red tube was first manufactured in 1939 and preceded the American M2 Sniperscope by four years. The ability to 'see in the dark' was a chance discovery from the early Farnsworth television camera. The Khaki covering made for easier handling in the marine environment. It was deliberately manufactured to look like a military water bottle in order not to arouse attention.
There is an article about this type of instrument by Dr Allan Mills, a friend of this museum, in the Bulletin of the Scientific Instrument Society Vol 34 (1992) p.23-25.
Thanks to all who have responded so far.