Telescopic Sighting System
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The Telescopic Sighting System (TESS) was a sight used on the FV4201 Chieftain tank{{Cite web|url=https://www.david-gledhill.co.uk/the-phantom/tess/|title=TESS :: David Gledhill|website=www.david-gledhill.co.uk}} and RAF F-4 Phantom aircraft.{{Cite web|url=https://bpag.co.uk/the-day-of-the-j/|title=The Way of the J. – British Phantom Aviation Group}}
Usage
The TESS was trialed and introduced in the early 1980s originally as a tank sight for the FV4201 Chieftain. Surplus stocks were used on F-4 Phantom aircraft operated by the Royal Air Force as a cost-saving measure for a long range daytime target identification device, whereas the United States Air Force used the TISEO on their F-4 Phantoms. The TESS was installed in the rear cockpit in the centre window section for the Radar Intercept Officer to use.{{Cite web|url=https://www.key.aero/article/front-line-raf-germany-phantoms|title=ON THE FRONT LINE: RAF GERMANY PHANTOMS|date=September 21, 2017|website=www.key.aero}} It was boresighted to the aircraft weapons system and when locked on target, the target was magnified six times.{{Cite web |title=McDonnell Douglas F-4J(UK) Phantom II Aircraft Data |url=https://www.airfighters.com/plug.php?o=pgalleryacd&mode=info&photoidx=312175 |access-date=2024-01-03 |website=airfighters.com}}