English Telescope Makers & Designers of the Twentieth Century

English telescope makers & designers of the twentieth century.

By Peter Abrahams.

Astro-Systems; Banks; Barnett; Bassett & Gowin; Burnet; Clarke-Smith; Cox, Hargreaves & Thomson; Fuller; Hargreaves; Hinds; Hindle; Hysom; Irving; Reid; Roberts; Slade; Telescope Technologies; Tel-Optics; Tweedale; Wildey; Willstrop; Wynne.

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Astro-Systems Ltd. Luton, Beds. Robbie Miller, ex-Fullerscopes employee. 10 cm to 30 cm telescopes, equatorial mounts. Low cost, made of sheet & tube metal, David Hinds optics. Advertisement Hermes July 1980, 4 inch mirrors to 24 inch Cassegrains. Review of 10 inch Newtonian, Hermes July 1980. Bedford Astronomical Supplies, same address, Peter Drew, makers of Maksutovs, 90 mm, David Hinds optics. (1978)

William Banks. 40 Newport Street, Bolton. Maker of equatorial mounts. Refiguring & resilvering of Newtonian mirrors. Author of Telescopes: Their Construction, Adjustment & Use.

Leslie G. Barnett, reflectors, Slough, Newtonians, traditional, alt-az, wooden mount. 8.5 inch Newtonian on an equatorial head, without stand. 8.5 inch size chosen because Henry Wildey wrote that an 8.5 inch reflector was the equivalent of a 6 inch refractor. Mirrors made by Barnett or possibly by Wildey, who is still alive.

Bassett & Gowin. Saltdean, Sussex. 'Makers of astronomical mirrors and accessories, Parabolic mirrors 6 inch to 24 inch, 1/10 wave accuracy, flats, kits, mirror cells', advertisement in Hermes, 1968.

W. Burnet & Son. Boston, Lincs. 'Makers of astronomical telescope eyepieces and components, Ramsden eyepieces 1/4 inch to 1 1/4 inch', advertisement in Hermes, July 1969.

Captain G.T. Clarke-Smith. Engineering at Alvin Motors, developer of the iron lung. Fabricated a refractor; and a fork mounted 18 inch Newtonian / Nasmyth reflector, used by Clarke-Smith, then donated to Manchester university in the 1950s for use at Jodrell Bank, and now at Salford Observatory (missing the Nasmyth optics). There might be an identical telescope in the US. The primary is glass laminated onto a back, possibly made by Grubb Parsons, possibly in a bid for a larger scope - the truss tube resembles a scaled down Pretoria reflector ( ). There are no makers marks visible on any of the castings. The main bronze worm wheel on the RA axis is from David Brown engineering. An image of the telescope at Salford Observatory: (Information on Clarke-Smith from Martin Brown)

Cox, Hargreaves & Thomson. Astronomical telescopes, optics only. John Hargreaves designed the telescopes, and worked in the patent office. John Victor Thomson had made a 36 inch mirror for the spectrograph on the Palomar 200 inch. The mechanical parts were subcontracted to H.G. Barlow & Son, who built the telescopes. (Unknown whose name appeared on telescope). H.W. Cox and his brother L.A. Cox, were the first in England to make Schmidt cameras, see ATM books, JBAA 48 (1938) 308-313, JBAA 50 (1939) 61-68.

Dudley Fuller. Fullerscopes. Used optics by Wildey, Hinds, AE Optics. Early models were marked 'Fullerscope'.

Frederick J. Hargreaves, mirror maker, very skilled, 47 inch for Uccle in Belgium, taught Wildey, President of BAA, Jupiter observations & drawings.

David Graham Hinds, amateur astronomer, made mirrors in the 1940s & 1950s, a friend of Henry Wildey.

David Hinds. Tring, Herts; and Hemel Hempstead, Hertfordshire. Son of D.G. Hinds. Produced hundreds of mirrors, 6, 8 and 10 inch, excellent quality; supplied Broadhurst Clarkson, Fuller, and many other manufacturers & retailers; supplied flats to AE Optics; performed aluminizing for many firms, but later stopped production & now retails commercial telescopes:

John Henry Hindle (2 Nov 1869 - 17 May 1942)

Hindle was self-taught, worked as an 'ironmaster', and was owner of Hindle, Son & Co., Ltd., Engineers, of Witton, Blackburn. The business patented & produced baling presses and looms for weaving cotton or wool felts used for drying paper. By the mid 1890s, Hindle was a consultant on electrical motors and dynamos. He patented controls, safety devices, and electromagnetic brakes for hoists and elevators. He started his own engineering business in 1910, first in Manchester, then moving in 1918 to Haslingden, and then to Blackburn, where his Union Engineering Works served the textile industry. His only son Thomas assisted and continued the business after Hindle's death.

Hindle made many mirrors, including some of the larger amateur telescope optics of his era, as an avocation, giving the mirrors to various observatories. A 25 inch mirror was kept and used by Hindle, and a 20 1/2 inch mirror was given to W. H. Steavenson.

His largest telescope was a fork mounted equatorial 30 inch Newtonian, weighing 3557 pounds, for Cambridge University Observatory (Scientific American, September 1939), installed at Cambridge, then sent to the Cape of Good Hope, back to Cambridge, and then to Spain. Albert Ingalls published Hindle's description of the project in his column in Scientific American for September, 1939, noting that it was the largest amateur telescope known to Ingalls, made since the ATM movement began in 1926. A 3 1/2 inch blank of Chance glass was ground to f4 and mounted in an 18 point Hindle cell. The tube was thin sheet steel, braced with tensile steel wire; and the secondary electrically heated. The electric drive used a gramophone motor, with a governor that was braked or released for slow or fast tracking, and a separate motor for slewing.

The Hindle test for Cassegrain & Gregorian secondaries, using a large spherical mirror (the 'Hindle sphere') to produce an image of the surface of the secondary, has been a standard test since its introduction in 1931. After he published this test, the Dominion Astrophysical Observatory in Victoria commissioned Hindle to fabricate a 19 1/2 inch secondary for the 72 inch DAO telescope, but it is unclear if this job was accepted or completed.

Hindle designed a grinding and polishing machine that used an 'ovoid stroke', declining to patent it, but publishing a description in the 'Amateur Telescope Making' books.

World travel was another avocation of Hindle, visiting many observatories and witnessing the pouring of molten pyrex to form the 200 inch disk for Mt. Palomar.

References:

Hindle, John. The Compound Telescope-Cassegrainian and Gregorian Types. The Mechanical Flotation of Mirrors. How to Make a Diagonal for a Newtonian Reflector. Chapters in 'Amateur Telescope Making' and 'Amateur Telescope Making-Advanced', edited by Albert G. Ingalls, various editions.

Hindle. Correspondence with Ellison, carried in the 'English Mechanic' during 1926, on the subject of thermal effects on telescope mirrors and how changes in temperature can effect observations.

Hindle, J.H. A New Test for Cassegrainian and Gregorian Secondary Mirrors. Monthly Notices of the Royal Astronomical Society 91 (1931) 592-593.

Hindle, John. The Pouring of the 200-inch Mirror Disk: An Eye Witness Account. JBAA. 45 (1934) 200.

(Hindle) Porthouse, William. Hindle, John Henry. 1869-1942. Monthly Notices of the Royal Astronomical Society 103 (1943) 66-67.

(reprinted: Ingalls, Albert Graham. Telescoptics. Scientific American 170:5 (May 1944)

Ingalls, Albert G. An Amateur 30" Reflector. Scientific American, September, 1939.

Photos of Hindle's work appear elsewhere in the ATM books; the 30 inch blank on a grinding machine is seen on page 245 of ATM, fourth edition, 1935; and the 20 1/2 inch is on page 453 of ATM.

Jim Hysom.

Hysom, born 1933, made his first mirror at 17 years, a 6 inch f8, and then wrote to Horace Dall.

He began his career at Cox, Hargreaves, and Thomson. His first assignment as an optician was three 11 1/4 inch plane parallel windows for a 10 inch Cassegrain at Woomara rocket test site in Australia, which was tested by placing in front of a collimator and using a knife edge test. Optician John Mortleman became Hysom's most influential tutor.

His next job was at Optical Surfaces, where almost all of the work involved making etalons and other physical optics, until they hired a manager from Hilger & Watts, who decided to cease production of amateur astronomical optics, the product most important to Hysom.

Circa 1962, the Leicester Astronomical Society formed the Leicester Astronomical Center with a winter project of building 6 inch f8 telescopes. Mike Goddard and Cliff Shuttlewood decided to expand the project into a business; Goddard supplied the financing, had an honors degree in physics from Oxford, and a family business of Wadkins power woodworking tools. The business was called Leister Astronomical Center Ltd, fabricating 6 inch f8 and 8.5 inch f6 telescopes designed by Shuttlewood, who also made the optics. While at Optical Surfaces, Hysom made mirrors for LAC, and they soon hired Jim Hysom for optical fabrication.

A 2500 square foot factory building was found in Luten, Hysom's home town, and the business grew to 12 employees. 12 inch reflectors were added to the line.

The business became Astronomical Equipment around 1967.

The business split into AE Optics & AE Mechanics circa 1977. AE Optics closed around 1993, when Jim continued business at Hytel Optics.

Astronomical Equipment was comprised of Jim Hysom and his younger brother Robert, who was a machinist and handled mechanical production. Robert later founded AE Mechanics, when Jim's business was renamed AE Optics. Cliff Shuttlewood designed and engineered the telescopes. The business lasted 10 years

Products included Newtonians, Cassegrains, Newtonian-Cassegrains. Hundreds of 6 inch and 8.5 inch telescopes were produced. Very few AE telescopes were imported to the U.S., circa 1974, but their open tube design was not successful in the U.S. 8 inch Maksutovs were produced. Over 100 3 1/2 inch Maksutov front elements were made and matched with primaries made by David Hinds.

A 12 inch fork mounted telescope carried the label Astronomical Equipment.

16 inch equatorial telescopes to universities: Hatfield Polytechnic, upgraded to 20 inch with the same mount and an improved drive, later moved to University of Hartford. Leicester U. Cardiff U. Armagh Observatory. These cost 2000 pounds in 1968, and used the same drive as the 12 inch telescope, that had problems with periodic error.

24 inch Cassegrain optics, 108 inch focal length, for University of Keel, supplied with a Newtonian secondary that was not used.

33 inch glass discs cut to hexagonal profile, slumped & figured, 94 of these sold to CERN at Geneva for use in a Cherenkoff radiation detector and 33 sold to Fermi Lab.

Cassegrain secondaries were tested by grinding & polishing the back into a sphere, resulting in a meniscus profile, then tested from the back with the Dall null test using test lenses made by Dall. Later procedures 'incorporated' the Dall null lens into the profile ground in the back of the secondary, which worked well. Dall and Hysom both realized that if a wedge was put in the meniscus, the two surfaces could be more easily differentiated under test. This procedure was used to make the secondary for the 30 inch Steavenson telescope at Royal Greenwich Observatory. The procedure was also derived & published by (Frank Cooke) in Applied Optics.

Cliff Shuttlewood in photo in the middle of large sheet.

AE Optics sold Russian binoculars in the late 1960s, at the suggestion of Horace Dall.

After AE Optics closed, projects completed by Hysom included:

-12 inch replacement objective for the Northumberland telescope.

-Three mirror telescope, optics fabricated to spherical surface by Hysom and figured by Willstrop.

-36 inch mirror for Cambridge.

-41 inch plate glass slumped by George Hall, refigured by Hysom, for detection of cosmic rays in the atmosphere.

-0.5 meter mirror for Cambridge Astronomical Society, 1992.

-COAST optics: five 16 inch paraboloids, five 20 inch flats, five tertiaries, and over thirty 4 inch flats, each unit producing a parallel beam. All optics were of Zerodur and figured to 1/20 wave. COAST was designed by the Cambridge University physics department, installed near Cambridge, and has resolved Capella and observed 'star spots'.

H.N. Irving. Teddington, Middlesex. Made mirrors since before WWI. 6 1/2 inch Newtonian. 1978, reflectors 15 cm to 30 cm, optics from Hinds. Refractors 3 inch, 2 1/2 inch, 2 1/8 inch. Author of: Hints and Care on the use of the Reflecting Telescope, n.d., 8pp. 1973, making mounts & eyepieces, not mirrors. Son, Ron Irving, an instrument maker, not an optician.

Esmond J. Reid, complex commercial & miliary optics, was an employee of AE Optics.

Austin Roberts & Co. Birkenhead, Cheshire. Started 1967 by a group of ATMs. Reflectors, 115 mm and larger. (Hermes, 1973)

W. Slade. Conham Hill, Hanham, Bristol. Astronomical telescope maker, flats, refiguring & resilvering of mirrors. Employee of Hindle.

Telescope Technologies, 2 meter primaries contracted to Zeiss, made in Russia; secondaries by Sinden. Neil Parker, chief mechanical designer, employee at RGO.

Tel-Optics. Frome, Somerset. 'Manufacturers of Telescope Mirrors, specialise in supplying complete Kits for 4 inch to 10 inch mirrors', advertisement in Hermes, October 1970. (ATM supplies, not finished mirrors?)

Charles L. Tweedale. Articles in English Mechanic circa 1894. Invented a zonal test.

Henry Wildey. Mirror maker, some of good quality, up to 16 inches diameter, active Jupiter & Saturn observer in the 1940s. 1978, one man business, supplies complete telescopes, makes eyepieces.

Roderick Willstrop. Optical designer.

Fabricated several telescopes: 7 inch f7 mirror. 5 1/4 inch doublet objective glass. Three mirror telescope, 4 inch prototype, 2 3/4 inch perforation, leaving an annulus of glass 6/10 of an inch wide with a complex surface profile that is 7 fringes aspheric. Three mirror telescope, 20 inch aperture with 10 inch perforation, f1.6 primary, glass taken to spherical by Jim Hysom & figured by Willstrop.

Designed 12 inch doublet now in Northumberland telescope.

Designed the 'three mirror telescope',

Willstrop, R.V. MNRAS 210 (1984) 597-609. 3 mirror telescope, one design optimised for a fully illuminated 2 degree field, another with a 4 degree field having the central 2 degrees fully illuminated, and vignetting outside that area. The flat field version has a field of about 3 degrees.

MNRAS 225 (1987) 187. Three mirror telescope scaled up to an aperture of 5 metres.

There is a description of the optical null tests I used in making the prototype, and suitable tests for the big one, in Optics in Astronomy, ed. J.V. Wall, Cambridge University Press, 1993 (Proceedings of the 32nd Herstmonceux Conference, held 9 - 11 Sptember 1991), see Chapter 12, pp. 139 - 155. This reference also has a reproduction of part (44 x 64 arc minutes) of one of the better photographs I had taken at that time. Roderick Willstrop.

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01 November 2002