Astronomical Devices

Astronomical Devices

By the 1830s Grubb had established an engineering company near Charlemont Bridge in Dublin.  In 1833 he was commissioned by Edward Cooper [1798-1863] telescope_drawing_tnto assist in the construction of what became for many years the largest refractor telescope in the world located at his Observatory in Markree Castle in Sligo. This had a 13.3 inch objective lens with a focal length of 25 feet and Cooper had purchased the optics for the refractor in Paris.  This project “marked a major advance in ensuring the stability and control of massive telescopes”   Following the success of this venture Grubb was approached by Thomas Romney Robinson, [1792-1882] the Director of the Armagh, to construct the Observatory’s 15 inch reflector. Robinson was a noted mathematician and was Director of the Armagh Observatory from 1823 until his death in 1882.  Grubb introduced a number of new concepts into his design of the Armagh Observatory reflector.  These innovative concepts, such as a clock-driven equatorial mount and the positioning of the eyepiece at the rear of the telescope, which worked because there was a hole in the centre of the primary mirror, subsequently became the standard design.  In this work and subsequent projects Grubb and his company was,

“…able to achieve substantial improvements in the mechanical aspects of telescope design, the stability and the capacity to control reliably the position of the telescope axis, and to vary it systematically for considerable periods in order to track stars.”

He was also commissioned to carry out some work for William Parsons, 3rd Earl of Rosse [1800-1867] who built what was then the largest telescope in the world with a 6 foot diameter mirror.

Later Years

In 1867 Grubb received an order: to build a 48-inch reflector for Melbourne Observatory in Australia thus establishing the firm as a central player in the business.  To fulfil this order Grubb established a new factory “Grubb’s of Dublin” at what later became known as Observatory Lane, Rathmines.  This Melbourne commission was for “the largest reflecting telescope in the world” and in a short note on the Powerhouse Museum in Sydney by Geoff Baker Assistant Curator written in 2008 we are told that during construction the “entire roof of the workshop went up in flames.”  Following completion of the device a group representing the royal Society including Lord Rosse, Dr. Thomas R. Robinson and Warren De La Rue [1815-1889] viewed the piece and enthused that it was a “masterpiece of astronomical mechanism.”   However while the project while successful in establishing the reputation of the company internationally the success was somewhat marred by the reconstruction of the telescope in Australia when considerable and irreparably damage was done to parts of the delicate equipment.
The new company specialised in the manufacture of large telescopes and became leading international suppliers of telescopes and astronomical equipment. Grubb’s of Dublin constructed a 27 inch lens diameter refracting telescope for an Observatory in Vienna and supplied telescopes for facilities in Glasgow and Dunsink, near Dublin.
During the planning of the Melbourne Telescope Howard Grubb, son of Thomas who had joined the company in 1865 was assigned to manage the project.  howard_grubb_tnHoward (pictured right) took control of the Company in 1878 upon the death of his father.  He continued his father’s success and the Company reached its zenith by the end of the 19th Century as Grubb’s of Dublin became one of only six companies in the world capable of handling the major astronomical projects.  During World War I Grubb’s were involved in the manufacturing of optical systems for the army.  They produced submarine periscopes and telescopic sights for rifles. In fact the company became the “prime supplier of optical range-finders and periscopes for the British navy.”   For his innovations Howard was elected a Fellow of the Royal Society in 1864, and was knighted in 1887. Grubb’s of Dublin remained in operation at its Rathmines Plant until the end of British rule in Ireland.  In 1925 the factory was taken over by the Parsons Company led by Charles Algernon Parsons [1854-1931] son of the 3rd Earl of Rosse and the business was transferred to Newcastle in England.
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