David Sinden:'A Life in Optics' by John Nichol

 In the late 1960’s my interest in astronomy led me to attempt to make a telescope, mirror and all. Trying to learn the art of grinding and polishing a fine optical surface from a book was difficult. About that time I heard of a telescope mirror making class being held locally by Jack Youdale, one of the first amateur telescope makers in the UK to make a Maksutov telescope. Filled with enthusiasm, I joined the class and completed my first mirror. I had discovered a love of optics that was to enrich my life and bring me much pleasure. Jack would frequently talk about David Sinden, and his many impressive achievements as chief optician with Grubb Parsons. Fortunately, it was not long before I met the charismatic man who was to further fire my enthusiasm for optics and telescopes. What follows is a brief account of some of David’s many achievements.

Thomas Grubb is a name synonymous with world quality astronomical telescopes. The firm of Thomas Grubb, established in Dublin in the early nineteenth century, produced many of the world’s finest astronomical telescopes, the company was known for quality and innovation. In 1868 Thomas retired and his son Howard took over the running of the business. In 1918 Grubbs relocated to St Albans. Hard times beset the business and it was bought by Sir Charles Parsons (son of the third earl of Rosse, who was famous for his 72 inch telescope). The new business, Sir Howard Grubb Parsons and company, was relocated to Newcastle in 1925. The last chief optician at Grubbs (as the company was called by its employees) was David Sinden.  David rose from humble beginnings to work on some of the largest optics made in the UK. After the untimely demise of Grubbs in 1984 (the actual date of closure varies depending upon the reference used), David set up his own business, the Sinden Optical Company, and went on to produce many fine optics until his death in 2005. David represented the last in a line of highly respected optician’s traceable back to Thomas Grubb and the third Earl of Rosse, a pedigree of some distinction.

David was born in Hartlepool on 31st July 1932, he subsequently moved to Haverton Hill and then onto Billingham before moving to Newcastle after his appointment to Grubb Parsons. From an early age David became interested in astronomy, at the age of sixteen, encouraged by his father Fred, David made a six inch parabolic mirror which was mounted in a telescope made with the help of his father. David made the drawings for the instrument and his father fabricated the parts. The telescope caused a stir around Hood Street, Haverton Hill, and neighbours dropped by to view the moon, planets and stars with the telescope. The local press featured the story with a picture of the telescope and father and son on Friday November 26th 1948. David was always tinkering and trying to find out ways of doing things. Leslie, David’s younger brother recalled a couple of examples. On one occasion David’s mother had asked him what he wanted for his birthday, David replied, ‘a bin’, which he subsequently got. David wanted to make a casting from aluminium; he devised a setup based around a metal dust bin. The bin was pieced in several places to allow air to pass through it. A fire grate was placed in the bottom of the bin, together with some coal. A ladle containing the aluminium to be melted was fixed near the top. Finally, a vacuum cleaner was used to blow air through the apparatus to achieve a high enough temperature to melt the aluminium. The project was a success and the casting successfully made.  On another occasion the outcome was not so successful. David wanted to braze some metal and came up with the idea of using a vacuum cleaner to blow air together with domestic coal gas in order to produce a flame with the required heat. The apparatus was set up with Leslie turning on the gas and electricity and David trying to ignite the mixture, several unsuccessful attempts were made, then unexpectedly, the vacuum cleaner shot off like a rocket with a tail of flames shooting from the rear. Fortunately, no permanent damage was done, the vacuum cleaner survived and David’s mother, who was not at home during the experiment, was none the wiser.

Ray Townsend, a good friend of David’s and fellow apprentice at the local ICI works recalls that David was a keen cyclist. Ray would pace David at ever faster speeds whilst riding his BSA motorcycle. But David was not only interested in riding quickly; he also managed to win a standing still contest on his bicycle. I remember David telling me that he used to take part in cycling time trial events on some of the same courses that I had ridden in my cycling days. David eventually decided to get a motor between his two wheels and bought a motorcycle. Ray Townsend recalls, ‘He bought himself an old 250 cc motorbike, it was a New Imperial and it really needed some TLC.  In no time he had transformed it.  I’m not sure which he enjoyed the most – riding it or restoring it.  Restoration or creation, be it telescopes or motorcycles, Dave had the magic touch that made it happen.’

 

 

David became more and more dissatisfied with his experiences at I.C.I. as an apprentice fitter, both the environment and the nature of the work was not to his liking.  When he had completed his apprenticeship he left I.C.I. and started work at Durkins (a local optician), as an expert in optical instruments (much to his father’s disapproval).  In typical style he designed and built some apparatus for collimating binoculars. David was much happier dealing with that kind of work and it eventually led him to his work at Grubb Parsons.

 

In the late 1950’s David sent a mirror of his own making to Grubb Parsons, they tested it and were so impressed that they employed him. David was quick to progress and by 1961 he was promoted by David Brown to the post of optical manager. The pair formed a formidable team and went on to produce many world class optics. David Brown was an influential figure in the development of post war astronomical telescopes; he died prematurely at the age of just 59 on July 17th 1987. Brown’s contributions to astronomy earned him an honorary doctorate from Durham University in 1981. In many ways he could be regarded as a British version of the great American astronomer/telescope maker George Ritchey.

 

The 1.2 M McKellar Telescope

The Brown Sinden years at Grubbs produced many fine telescopes, including in 1961, the 1.2 metre McKellar Telescope at the Dominion Astrophysical Observatory in Victoria, British Columbia named after Andre McKellar, the first to discover the temperature of interstellar space and the presence of organic molecules in the same medium.  1962 saw the pair produce a very fine 40 inch mirror for the Pic du Midi observatory, France. The tube and mount were produced in France. The telescope was funded by NASA and its purpose was to take high resolution photographs of the moon for use in the space programme. The telescope is still in use, and producing the highest quality images, a testament to the quality of the optics.

 

 

1963 saw the completion of the Elizabeth telescope, 40 inches in aperture and destined for South Africa. Originally sited in Cape Town the telescope was subsequently moved to a superior location at Sutherland. In the same year they produced a 72 inch telescope for Helwan in Egypt. This was one of five 72 inch telescopes made by Grubbs over the years. Additionally, they made a 72 inch telescope without optics for the Haute Provence Observatory in France.  Unfortunately, the Helwan mirror was damaged when the telescope was relocated; the replacement mirror was made in Germany.

 

 

 

David Sinden (on the left) and George Oliver with the 72 inch Helwan mirror.

 

1966 saw the completion of a 30 inch Telescope for Jungfraujoch, Switzerland. The observatory is spectacularly sited high up on an alpine peak overlooking a glacier. The following year Grubbs completed, at the behest of no lesser authority that the Vatican, a 16/24 inch Schmidt camera to be sited at Castel Gandolfo. 1967 was an important year for the two David’s, with it came the completion of the 98 inch Isaac Newton Telescope (INT). After years of planning and deliberations the instrument was sited at Herstmonceaux, England. The June 1965 issue of Sky and Telescope magazine featured a front cover image of the 98 inch mirror with David standing alongside it, a proud moment indeed. There are many anecdotes associated with Grubbs, one which David told me, concerned the INT mirror. The cavernous workshops in which the mirrors where made had large overhead cranes running on rails on either side of the building. It was a regular occurrence for a big mirror to be moved off the machine for testing or some other reason. One day the Isaac Newton mirror was lifted from the polishing machine when it began to sway this way and that as it was being moved. David Sinden realised that the mirror was going to collide with the workshop wall if immediate action was not taken. As if by reflex he raised his arm between the swaying mirror and the workshop wall in an effort to arrest the wayward motion. Miraculously, the beast responded and disaster was averted. It was only after the event that David realised how close to serious injury he had been.

 

 

 

The 98 inch Isaac Newton Telescope in the Newcastle works.

 

From its less than ideal location in East Sussex the 98 inch telescope did make some useful observations, but England was never really the ideal location. In 1979 the decision was made to relocate the telescope to La Palma, and a new mirror 100 inches in diameter made form a superior glass was produced by Grubbs. Unfortunately, David had left Grubbs by this time and played no part in making the new mirror.

 

 

1972 saw the run of large mirrors continue with a 72 inch mirror for Padua, Italy. 1973 was another high year for Grubbs with the completion of the 48/72 inch Schmidt camera for Siding Spring Australia. This important telescope would play a key role in mapping the southern hemisphere skys. The following year saw the completion of the 154 inch Anglo Australian Telescope. Arguably the pinnacle of David Sinden’s career, this was the last of the great equatorial telescopes to be built. The telescope has an excellent reputation and the quality of its optics are well regarded.

 

 

1976 saw the production of an unusual telescope mirror by Grubbs, this was the 150 inch for the United Kingdom Infra Red Telescope (UKIRT). It was unusual in that the mirror was thin by the standards of the day. As the telescope was intended for observations in the longer infra red end of the spectrum, the surface accuracy of the mirror did not have be as accurate as that needed for observing in the shorter wavelengths of the optical region. Consequently, the mirror blank could be thinner, thus saving weight and allowing for a cheaper telescope to be made. In the event, the mirror exceeded expectations and continues to make ground breaking observations. The following appeared in the September 2011 edition of Sky at Night Magazine; ‘Astronomer from Europe have spotted the most distant quasar ever seen. The luminous galaxy, which is powered by a black hole, is easily the brightest object that has been identified at such a distance from the earth. Astronomers discovered the new quasar, dubbed ULAS J1120+0641, in observations by the United Kingdom Infrared Telescope in Hawaii.’

 

   

Despite David’s involvement with massive telescope optics he never forgot his roots as an amateur astronomer. One of his projects at Grubbs involved the production of small telescopes for the amateur market. The Andromeda, was a 5 inch Newtonian reflector on an altazimuth mount. The Perseus, was a 9 inch Maksutov telescope aimed at the serious amateur astronomer.

 

The Andromeda

 

In the late seventies, despite the success of a series of large telescopes and optics, Grubb Parsons was in trouble. It was part of a much larger group of companies, and it would appear that making world class astronomical telescopes was not it’s main priority. Sadly, circumstances led to David leaving his beloved Grubbs in 1976. These were difficult times for the master optician. Grubbs went on to produce the replacement 100 inch Isaac Newton mirror and the 4.2 m William Herschel mirror, without David, before and finally closing in 1984. After a period of reflection David returned to making optics with the birth of his own Sinden Optical Company (SOC) in 1979.

 

Apple, one of the world’s most successful businesses, is said to have had it’s origins in a humble garage, and so it was the case with SOC in David’s garage in Walbottle, Newcastle. Before long the business was relocated to Byker in a small industrial unit bursting at the seems with the paraphernalia associated with optical work. The location of the unit was far from ideal with security being a constant worry. Eventually the business was moved to a larger unit in a more secure location in Ryton. A company website was established stating, ‘Our company was established in 1989 by David Sinden for the production of large and difficult optics for professional use. Previously, he had been chief optician for the firm of  Grubb Parsons in Newcastle-upon-Tyne, who’s reputation for manufacture of massive telescopes was famous world wide. For example…..the 3.9 metre Ritchey Chretien scope of the Anglo Australian Observatory used by David Malin for his wonderful astro photographs.’

 

The Sinden Optical Company was to go on to produce many fine optics and instruments, what follows is a brief outline of those achievements (not in chronological order)……

 

Loved by the Victorians, the Camera Obscura is a fascinating device. Best situated on a high point with commanding views over the local area, a camera obscura projects images of the locality onto a large circular table situated in a darkened room. The images are particularly vibrant and a pleasure to behold. The manufacture of the optics for the camera obscura became a SOC specialty. It all began with the one for the national flower festival, held in Gateshead in 1990. Unfortunately, like everything else at the festival it was disposed of at the closure of the event. 1994 saw a more permanent example being established at the Tivaria Tower, Cadiz in Spain. Lisbon, Portugal was to be the next recipient of a camera in 1997. The Spanish were obviously impressed with the Cadiz instrument, resulting in another one being established in Jerez.  The fifth camera saw an installation being made in Havana, Cuba in 2003. Although the original camera in Gateshead was lost with the closure of the flower show, there does remain one example of a Sinden camera obscura in the UK, at the Foredown Tower, Hove.

 

1998 saw SOC venturing into the restoration of classical telescopes, many made by the original Grubb company of Dublin, no one was better qualified than David to undertake these renovations. One of the first was the McClean telescope of the Norman Lockyer Observatory, Sidmouth. The instrument was a dual photographic and visual instrument and was fully restored by David. Interestingly, this telescope was featured by the BBC north east regional news programme. In it David is seen talking about optics and some of the machines which had been acquired from Grubbs after its closure, were shown in action. Most of the telescopes made by the original Grubb company were refracting telescopes, one notable exception was a 15 inch reflector made in 1835 for Armagh observatory. This instrument was lovingly restored to its former glory by SOC.

 

David (right) and Jack Youdale with the 15 inch Grubb Reflector.

 

 

David’s passion and gift for massive optics did not end when he left Grubbs, he was asked by a Japanese Observatory to make a 36 inch optical set. This commission was as a direct result of his reputation established at Grubbs. It was stipulated that the mirror must be made by David Sinden himself.

 

David with the 36 inch Indian mirror.

 

Although a big mirror, the 36 inch was not the biggest mirror made by David since leaving Grubbs. This honour goes to a 48 inch mirror made for an observatory in India. I well remember seeing this mirror being polished on a machine, originally used by Grubbs, a massive glass disk slowly rotating, with a large polishing lap moving purposefully across its surface, under the watchful eye of the master optician.

 

June 2005, a star is born! Well not quite, but David did receive the accolade of having a minor planet named after him in acknowledgement of his contributions to optics.  Asteroid 10369 Sinden, will for ever serve as a reminder of the master optician’s work. A presentation took place at SOC, Ryton by a group from Armargh Observatory in which David was presented with documentation about his own ‘star’.

 

In 1888 the Reverend Espin was appointed vicar at Tow Law, in County Durham, where he established an observatory with a 24 inch reflecting telescope. Espin was an interesting man and it would take many lines to do him justice.  After his death in 1934 the observatory became neglected and fell into disrepair. Many years later David was to restore the 24 inch telescope, originally made by Calver, to it’s former glory and present it to Newcastle University. The telescope was installed in a large dome situated at Close House in the Tyne valley. I had the good fortune to visit the observatory on a number of occasions in the late 70’s and early 80’s. Today, it would appear that the observatory has become neglected and has fallen into disuse. The old Calver telescope has seen it all before! Hopefully, common sense will prevail and this historic instrument will once again be cared for and valued.

 

In 1993 David was awarded the honorary degree of master of science by Newcastle University in recognition of his work. David was vey pround of this achievement and could often be seen sporting his University tie.

 

Fortunately, in astronomical optics, most mirrors are concave and as such form an image which can be tested by one means or another. However, some are convex and do not, by themselves, form an image that can be tested without additonal optics. The Ritchey Chretien (RC) optical system, as used by  many of the world’s largest telescopes, has a concave primary mirror and a convex secondary mirror. Both surfaces have highly aspheric surfaces, they are hyperbolic. So the RC secondary, a convex hyperbolic surface, represents a difficult challenge for all but the most accomplished of opticians.  David was asked to make, and successfully completed, such a mirror, with a diameter of 617mm, for the 2m Liverpool Telescope to be set up on La Palma.  The Liverpool telescope was one of a number of 2m aperture instruments which marked a revival of large telescope making in the UK, unfortunately Telescope Technologies of Liverpool, who made these instruments did not last for long.

 

Throughout the existence of SOC Saturday morning represented something of an open house. Amateur astronomers and telescope makers would gather at David’s workshop to seek advice and pick Davids brain on one subject or another. Inevitably David would end up telling one of his often repeated stories about some event that had taken place at Grubbs, the stories were always told with such passion that you felt like you had witnessed the event first hand. Strangely, the stories were never diminished by the fact that they might have been heard before. David was a character, he liked nothing more than to talk optics, usually for several hours. It has been said that he could have talked for England! A quick phone call to David was out of the question, there was always a lengthy explanation to what seemed like the simplest of questions. Patrick Moore had tried on several occasions to get David to appear on The Sky at Night, David for some reason, always resisted and unfortunately it never happened.

 

David once stated that his intention was to live to be 100 and make mirrors until he was 99. Unfortunately, this was not to be the case, he was sadly stricken with cancer. He did battle the illness and continued making optics as long as he possibly could. Here is an extract from a message posted on the Cloudy Nights forum on 1st August 2005:

 

I'm 73 years old now and two years ago I was planning to retire when I was 80. However, just about a year and a half ago I was hit with a serious Lung Cancer which is most likely to be terminal. Statistics indicate that I may not reach Christmas - tho' I propose to fight as well as I can.

Sorry to be so gloomy, Jack - just trying to transmit information.
 
 

I am dreadfully weak and just able to get out of my chair and walk to the nearest Tea-pot.

I'm drowning in E.Mails and have a crisis with my correspondence.

 

Sadly, David died shortly after on 29th August 2005.

 

 

 

David Sinden 1932-2005 RIP
 
Text copyright J Nichol 2012
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