As RUSSELL LEADBETTER found, behind the anniversary lies an intriguing story of a firm which first became famous as Barr and Stroud.
ARCHIBALD BARR and William Stroud were neighbours and academic colleagues - and one day, in 1888, they decided to work on something new and adventurous.
Their efforts would lead to a company bearing their names which would become a world leader in the design and manufacture of optical equipment and systems.
Barr had been born in Glenfield, near Paisley, in November 1855. Stroud, from Bristol, was the son of a yarn merchant.
In time they found themselves in senior positions at Yorkshire College - today's University of Leeds. Barr was the professor of engineering, and Stroud held a top position for science.
Early on May 26, 1888, Barr, 32, dropped in on his neighbour. They had worked together on various projects but when Barr read a War Office advert he sensed a chance to really achieve something.
The ad called on inventors to submit designs for a military rangefinder suitable for use by the British Army.
Neither knew anything about such a device.
Stroud later recalled: "In blissful ignorance of what had already been done on the subject we dashed off regardlessly. The first rough instrument we made was a ghastly failure," he added.
But the pair persevered and within a month had taken out their first rangefinder patent. They produced a working model, which the War Office rejected as 'not suitable'.
The idea, however, showed promise, and they raised funds to build a better rangefinder, which was trialled in a compet-ition on HMS Arethusa in 1892.
Their version won and the Admiralty placed orders. Soon orders were received from Japan, Germany, Russia, Sweden, Turkey, Brazil, Italy and Chile.
Barr was by now Regius Professor of Civil Engineer-ing and Mechanics at Glasgow University and the company, Barr & Stroud, continued to grow.
By 1904, it was employing 100 men at a purpose-built factory in Anniesland and Stroud relocated to Glas-gow, to join Barr running it.
Thousands of range-finders were manufactured in the run-up to the First World War, and the firm was also producing trench periscopes, submarine periscopes and gun sights.
After the war, Barr & Stroud diversified into devices for civilian use, and the 1920s again saw a rise in demand for its rangefinders, for shipping and commer-cial purposes.
THE firm was also the sole supplier of submarine periscopes to the Royal Navy and many overseas navies.
When the clouds of war again hovered over Britain, Barr & Stroud focused its drive on military devices. Its workforce rose from 2000 to 6000 between 1939 and 1944 when it made 30,000 range-finders, 150,000 gun sights and bomb sights. It also made 2000 pairs of binoculars per month.
The Luftwaffe, recognising Barr & Stroud's contribution to the war effort, made plans to bomb the factory, but the attack never came.
Sadly, neither founder lived to see the firm's prodigious wartime successes. Barr died in 1931 at his Milngavie home, aged 76. Stroud died in 1938, in Torquay. He was 79.
After the war, the company developed new equipment for Britain's armed services. In later decades it supplied laser rangefinders for tanks and supplied advanced electro-optics for the guidance system in British Aerospace's Rapier missile project.
It also developed thermal imaging equipment for Britain's Swingfire missile system, and supplied Thermal Observation Gunnery Sighting Systems for tanks.
In 1977, Barr & Stroud merged with Pilkington, then in 2000 that company became a subsidiary of French firm, Thales Group. In 2001 Barr & Stroud Ltd became Thales Optronics Ltd. In Thales' words, the optronics business started by Barr & Stroud "is considered to be one of the oldest, if not the oldest, part of the global Thales Group".
Some 700 of Thales UK's 7500 workforce are based at Linthouse, which designs and manufactures electro-optic night vision systems and equipment for all three UK armed services and other defence forces worldwide.
THE site is also home to a team of transport specialists who work on communications and safety systems.
Around 30% of employees at the Glasgow facility are engineers and scientists.
"Prof Barr and Dr Stroud placed great emphasis on training and developing employees, a value shared by Thales UK today," said Stuart Boulton, vice president of Thales's global optronics business and head of the Glasgow site.
"We couldn't think of a better way to mark 125 years in business than to reaffirm our commitment to training young people from the local area with valuable engin-eering, technical and business skills."
In 2008, the Barr and Stroud brand name was brought back to the UK and the trade mark was re-registered. The present trade-mark owner, Optical Vision, makes binoculars and telescopes and keeps Barr & Stroud "at the forefront of the optics market".
The old company has come a long way in 125 years.