Manchester Astronomical Society
Established 1903

John Henry Hindle, 1869 - 1942

John Henry Hindle was nominated for membership of the Manchester Astronomical Society in November 1917. He later became vice-president. He was elected Fellow of the Royal Astronomical Society in June 1922. By the 1930s, he was internationally recognised as a telescope maker, optician and innovator, one of the leading optical experts of the time.

Born in November 1869, he was educated to elementary standard at the local school, close to his birthplace at Edenfield, in the Rossendale Valley, Lancashire. But he was largely self-taught, commencing work at the age of twelve as a half-timer in the textile industry in 1881. He started full-time work the following year and in his spare time also worked in an iron foundry and workshop. Hindle developed an interest in engineering, particularly electrical engineering, which he used to his advantage. By about 1895, he was a consultant on the design and manufacture of electrical motors, dynamos and hoisting equipment, patenting automatic control gear and an electromagnetic brake and safety mechanism for electric passenger and goods elevators. But with the close proximity of Cottonopolis, and aware of the demand for innovative technology, he became a highly respected textile machinery manufacturer in his own right, setting up a business in Manchester in 1910, when he was forty years old. Eight years later, he removed to the Union Engineering Works, Haslingden, where he designed and built machinery for the Lancashire cotton spinning and textile weaving industry.

Precision engineering fascinated him, in particular the construction of big telescopes. He made his first telescope mirror in 1910 and twenty-five years later, nearing what would now be considered as retirement age, he was a world authority on the subject. By then, he not only had the financial means to support his expensive hobby but could sell the results of his expertise. In this respect he might be considered on par with James Nasmyth, the Manchester engineer and telescope maker of the mid 19th century.


Hindle built many large reflecting telescopes including a 20.5-inch Newtonian-Cassegrain, of 8 and 30 feet focal length, and a 30-inch Newtonian. Both of these instruments were for his friend, Dr William H. Stevenson, former president of the British Astronomical Association and Director of the Mars Section. The 30-inch was mounted at Cambridge University Observatory, by arrangement with Sir Arthur Eddington. It was described in detail in Scientific American, September 1939. Hindle also built a 25-inch Newtonian reflector, of 15 feet focal length, for himself and a 17-inch instrument for Mr. H Leslie Dilks, another MAS member.

Image © MAS



He had a very unusual, totally enclosed observatory, erected on the Lancashire moors. It housed a large parabolic mirror, mounted facing downwards from inside the roof and fed with light from an equatorially mounted coelostat of 25.5 inches in diameter. Light was reflected from this to the paraboloid and then, via a tertiary flat, to a fixed eyepiece. Another mirror, picking off light from the coelostat, fed a low power finder. His 12-inch reflecting telescope had a novel, inverted fork, the tines of which carried counterbalances for the telescope tube. The telescope on its upturned fork was cantilevered on a long, overhung, polar axis.

Hindle frequently travelled abroad in representation of his Company and always took the opportunity to visit major observatories. While in North America, in 1931, he observed using the 72-inch Brashear reflector at the Dominion Observatory, Victoria, British Columbia but noted that he was "very disappointed" with the star images. He had already described a new test for Cassegrain and Gregorian secondary mirrors (Monthly Notices of the RAS, 91,592,1931) and Professor Sampson, considering this test to be a great improvement on previous ones, later commissioned Hindle to make a new 19.5-inch convex secondary for the 72-inch telescope. Unfortunately, we don't know if this secondary was ever finished.

On the same trip, in California, he met with Professor Richey, formerly of the Mount Wilson Observatory and the man largely responsible for figuring the 100-inch mirror of the Hooker reflector. When he met Dr. George Ellery Hale, in Pasadena, he suggested his new method of testing Cassegrainian and Gregorian secondary mirrors. Hale later intimated that Hindle's test might indeed be profitably applied to the testing of the 200-inch mirror then under construction. Although Hindle had doubts that this great telescope would ever be completed, he was invited to see the pouring of one of the 200-inch blanks in 1934. This he described enthusiastically and vividly to William Porthouse. It is tempting to think that had he lived, Hindle would have been at Mt. Palomar to see the commissioning of the Hale Telescope, in 1948.

During a two-day stopover at Mount Wilson Observatory, where he observed with the 60-inch reflector (whose star disks were "quite in order"), he was given a guided tour of the 100-inch Hooker Telescope, then the world's largest. On his way home, via Chicago, where lack of time prevented him from visiting Yerkes Observatory, he had a meeting in New York with Albert Ingalls, associate editor of The Scientific American, who was primarily responsible for the great surge of interest in amateur telescope construction in America during the 1930s.

The descriptions of John Hindle's work have, for many years, been read by generations of telescope makers on both sides of the Atlantic in Ingalls' famous trilogy, Amateur Telescope Making, first published by The Scientific American, in 1935. He is best remembered for the invention of his ovoid-stroke mirror grinding and polishing machine and for multi-point mirror floatation systems designed to support, without flexure, very large telescope mirrors.



A Hindle mirror-grinding machine is still in use by the Norwich Astronomical Society having passed from Hindle to Dr C.R.Burch of Bristol University and then, in 1948, to the Cambridge Observatories. Here it was employed by Dr E.H.Linwood at the Cambridge optical workshop. On Dr Linwood's retirement, the workshop was closed and following a meeting of NAS member, Mr. B Mitchell, with Dr David Dewhurst, in 1971, a 760mm blank and the Hindle mirror-grinding machine came into the hands of the Norwich Society. Both were used in the construction of a 30-inch (760mm) telescope for their observatory. The machine was housed in the NAS wooden clubroom when this was destroyed by fire in January 1979. However, priority was given to rescuing the machine from the blaze and it sustained only minor damage to its paintwork and drive belts.

Hindle's reputation as a telescope maker encouraged others in the MAS to make their own instruments, a tradition that is still very much alive. It also attracted speakers such as his friend, Dr. W.H.Stevenson to give lectures in Manchester. One memorable talk was given in January 1932 when Dr. Stevenson, a close friend of the Herschel family, recalled a visit Observatory House, Slough, where William and Caroline Herschel had lived over a hundred years earlier. Dr. Stevenson illustrated his description of Herschel's observing methods with many pictures of his instruments, eyepieces and telescope parts and he gave a fascinating account of his own discovery of a large speculum mirror that had remained unknown, even to the family. It had been suspected that some items made by William had been left in a small boarded-up space under a small back staircase. A man had been brought in by Miss Herschel to enter this space but he reported that there was only a big circular metal lid there. The family had showed no further interest in this but Stevenson suspected that there might be more to it. He had the staircase dismantled and found that the metal lid concealed an original Herschel speculum mirror, hidden for 110 years. This was photographed in-situ before its removal and the subsequent repair to the stairs. Dr. Stevenson rounded off his talk with a slide he had taken showing Sir William's three, now elderly, grand daughters and a remnant of the great 40-foot telescope that Herschel had erected in his garden at Observatory House.

At the time of his death, in June 1942, after a long illness, John Hindle was governing director of the firm of Hindle, Son & Co., Ltd, Engineers, Witton, near Blackburn, Lancashire. He was one of the MASs most famous members and will long be remembered. Sixty years after his death, at the end of the 20th century, one can still find references to his inventiveness in telescope construction and mirror making in the 'Gleanings' pages of Sky & Telescope and in many other publications for amateur telescope makers. He is buried, with his wife, in Helmshore churchyard, Haslingden. His memorial bears the simple inscription:

"He helped them to look at the stars"

Post Script:

In November 2000, several members of the MAS visited Telescope Technologies Ltd at Birkenhead. Here we were shown three partly completed 2-meter robotic telescopes, the first large instruments to be constructed in the UK since the demise of Grubb-Parsons Ltd in the mid 1980s.

We were told that the wide field Richey-Chretien optics of these new telescopes are being tested by the very same Hindle Test devised by John Hindle seventy years ago, when he was a member of the Manchester Astronomical Society.

Kevin Kilburn, F.R.A.S.