A Substantial Observatory 3" Astronomical Transit Telescope

English, c.1899*, engraved 'ELLIOT BROS. LONDON' the transit on iron standard uprights with gun metal bearings, clamp provided for fixing altitude of the telescope, with long sensetive striding or axis level for adjusting the axis, telescope axis perforated for illumination of the webb lines at night by means of an oil lamp on a support to the side of the iron standard, focus is via rack and pinion to the eyepiece, telescope in large pine case with eyepieces, 90Deg eyepiece, oil lamp, axis level, and tools, standard in second large pine case,

Note: the telescope comes with 4 brass fixing screws on conical mounts. presumably these would have been set into a concrete pier and used to screw down the iron standard, they are still in the case and have never been used.

Dimensions:
Telescope length (closed) 83cm
stand height to bearing block 55cm

* Achromatic objective lens signed and dated 'Elliot Bros 4.7.99'

Provenance: originally bought at auction when the River Wye Navigation Trust, which managed navigation on the River Wye, had its functions and property transferred to the Welsh Water Authority in Febuary 1981.

for similar instrument see: https://ice-museum-scotland.hw.ac.uk/product/1987-001/

Footnote: In the 19th century, transit telescopes—also known as transit instruments—played a crucial role in both astronomy and engineering. Originally devised to determine the precise positions of stars by observing their passage across the meridian, these telescopes were mounted to rotate in a single vertical plane. Their design allowed for extraordinary accuracy in timing celestial transits.

Engineers soon adapted transit instruments for terrestrial use. William John Macquorn Rankine, in his 1894 Manual of Civil Engineering, noted their superiority over theodolites when laying out exceptionally long straight lines. A typical transit instrument consisted of a finely calibrated telescope mounted on a horizontal axis, allowing it to pivot vertically while maintaining directional precision. This made it indispensable for large-scale civil works, such as railway construction and canal planning, where absolute linear accuracy was essential.