by Dave Letcher

Sometime around 1515 – 1520 Leonard Digges was born in Barham, a parish in Kent, UK. He died about 1559. Digges was well-known as a mathematician and surveyor; in fact he is credited with the invention of the theodolite. Digges wrote on many topics including military engineering, surveying, and cartog-raphy, in English too rather than the Latin or Greek traditionally used for scholarly articles.

Much of what we know about Leonard Digges comes from writings by his son, the famous English mathematician and astronomer Sir Thomas Digges, who was born in 1546 and died in 1595. Thomas promoted the Copernican system and postulated the “dark night sky paradox” but more about him in a future article. It should be noted that, after Thomas’s father died, he was entrusted to the guardianship of a Mr. John Dee, whom historians regard as a Renaissance natural philosopher.

Thomas, in his 1570 book, “Pantometria” describes his father’s use of a “proportional glass” to view people and objects at a distance. Colin A. Ronan, FRAS (1920 – 1995), a British astronomer and specialist in the history and philosophy of science claimed that Thomas’s description is of a telescope, either a reflector or refractor. Ronan suggests Leonard’s invention of a functioning telescope dates to sometime between 1540 and 1559. Some have suggested that some of Thomas’s description is exaggerated, perhaps due to praise given to an adored father but other parts appear to be credible. In the quote that follows we read a portion of what Thomas wrote.

“… my father by his continual painful [painstaking] practices, assisted with demonstra-tions Mathematical, was able, and sundry times hath by proportional Glasses duly situate in convenient angles, not only discovered things far off, read letters, numbered pieces of money with the very coin and superscription thereof, cast by some of his friends of pur-pose upon downs in open fields, but also seven miles off declared what hath been done at that instant in private places.”

Writings by William Bourne (c. 1535 – 1582), an English mathematician and Leonard’s colleague have provided us with information about Leonard’s experiments using lenses and mirrors. Why don’t we know much more from Leonard himself? Probably because he took part in the 1554 rebellion-went-bad led by Sir Thomas Wyatt against Queen Mary. Leonard, initially condemned to death had his sentence commut-ed but he forfeited all of his estate.

Sources:
Leonard Digges (scientist). http://en.wikipedia.org/wiki/Leonard_Digges_(scientist) Retrieved October 24, 2012.

Greene, Nick. Leonard Digges. http://space.about.com/od/astronomerbiographies/a/Leonard_Digges.htm. Retrieved October 24, 2012.

Ronan, Colin. Leonard and Thomas Digges. Journal of the British Astronomical Association, 101(6):1991.

The first telescope? http://www.actionoptics.co.uk/The First Telescope.htm.