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The English mathematician Thomas Harriot was the first to study the Moon in detail using an astronomical telescope in 1609, and it is known with certainty that this occurred several months before Galileo Galilei, the famous Italian physicist, did the same. Galilei, however, was the first to have published his observations in a book entitled “The Starry Messenger” (translated from Latin). His book revolutionized our concept of the Universe.

The instrument did not become widely known to the public until 1608 when Hans Lippershey (or Lipperhey), a Dutch optician of German origin, began to make and sell telescopes. Lippershey applied for a patent for what he claimed was his own invention, but was refused on the grounds that the device was already in existence.

It is difficult to determine when a refracting telescope was first assembled using lenses. The first person to do so with certainty, and thus the person to be credited with its invention, was the English mathematician Leonard Digges who constructed a refracting telescope sometime between 1540 and 1553 to assist with his topographic surveys. Leonard Digges – or perhaps his son, the English astronomer Thomas Digges – was also the first to turn a refractor towards the sky to study celestial objects.

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The first refracting telescopes consisted of two lenses separated by some distance within a closed tube. The larger of the two is the objective, or primary lens, and the second is the ocular. The role of the lenses is to concentrate light rays into a single point – the focal point – so as to obtain a sharper magnified image.

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Evidence that lenses were in use during the first century BC can be found in the records of the Roman authors Pliny and Senecio who reported that an engraver at Pompeii used a lens to help him in his work. Other historical evidence reveals that the Arabs were using lenses by the year 600 AD, as were the Vikings around the year 900.

Among his many industry accolades, Robert was named Fellow of the International Society for Optics and Photonics, SPIE, in 2021. This prestigious honor is a distinction recognizing individuals for their technical accomplishments and for their service to the general optics community. Robert is a graduate of Georgetown University's McDonough School of Business and is an exceptional Horseman.

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We respectfully acknowledge the University of Arizona is on the land and territories of Indigenous peoples. Today, Arizona is home to 22 federally recognized tribes, with Tucson being home to the O’odham and the Yaqui. Committed to diversity and inclusion, the University strives to build sustainable relationships with sovereign Native Nations and Indigenous communities through education offerings, partnerships, and community service.

In appreciation for Robert’s arduous commitment to help advance the field of optics, the Robert M. Edmund Endowed Chair in Optical Sciences was established by his long-time friend and Edmund Optics board member, Dr. John P. Schaefer, and the Fredrick Gardner Cottrell Foundation.

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In 1942, Robert’s father, Norman Edmund, founded a mail-order company, Edmund Scientific, providing consumers with optical devices. Within a decade, Norman's small optical surplus company became famous as the go-to source for telescopes, microscopes, science toys and gadgets of every description. In 1976, Robert assumed the leadership role and has since overseen the growth and re-positioning of the company, now called Edmund Optics, to its current emphasis. Today, Edmund Optics is regarded as a leading producer of optics, coatings, imaging systems and photonics supporting the worldwide technical community.

There are several types of aberrations, the main ones being chromatic and spherical. All types of aberration cause deformation of the image transmitted by the telescope.

The Assyrians (people who lived in a region that is known today as Iraq) were perhaps the first to have used lenses to magnify objects, possibly around 1,500 BC. The evidence is a rock crystal discovered by the English archaeologist John Layard in 1850 during the excavation of the ancient city of Nimrud. The crystal was cut and polished into the shape of a lens, however it is not entirely certain that it was used as a magnifying lens and not as jewellery or for some other purpose.

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Unfortunately, we now know today that it is impossible to focus light from an object into a single point using only one lens. The phenomenon that prevents this from happening is known as aberration.

It is the glass of the lens that allows light to be concentrated. Glass is denser than air, and when light rays pass through it, they are bent from their path in different directions. This phenomenon is known as “refraction”. Lenses, to be effective in a telescope, must be shaped so that all the refracted light rays converge in a single point.

These days, refracting telescopes are made using several lenses that are designed and put together in ways that minimize the problems caused by aberrations.

Chromatic aberration occurs because light rays of different colours are not all bent by the same amount as they pass through a lens. Consequently, it is impossible to concentrate the rays into a single point. Chromatic aberration causes coloured fringes to appear around the image.

Robert M. Edmund, CEO and Chairman of the Board of Directors for Edmund Optics, is well known for his expertise in business strategy, optical manufacturing and product development, as well as global catalog marketing. He has over 50 years of professional contributions in the field of optics and photonics.

Among his commitments to the optics industry and education, Robert dedicated the company’s Edmund Scientific Division to outreach, teaching thousands of young students throughout the U.S. about optics each year. In addition, he has lobbied on Capitol Hill in support of optics for more than 30 years. He is also very involved with the University of Arizona, serving on advisory boards and is the founding chairman of the Wyant College of Optical Sciences Advisory Board.

Also at Wyant College, Robert established an undergraduate student scholarship, named for his father, and a graduate student scholarship bearing his own name to help further the academic and research interests of future generations of optical engineers.

Spherical aberration is due to the shape of the lens. A lens is nothing more than a piece of glass with each surface shaped like a portion of a sphere. Unfortunately, a sphere is not the best shape for concentrating light rays into a single point, but is the easiest shape to make when grinding and polishing glass. Spherical aberration causes images to be blurred.