Peter Barlow and the Barlow Lenses.
On October 13 1776 British mathematician and physicist Peter Barlow was born. He is still reknown today for his development of two varieties of achromatic (non-colour-distorting) telescope lenses, the so-called Barlow lenses. Despite lacking formal education, Peter Barlow became assistant mathematical master at the Royal Military Academy in Woolwich in 1801. His first research achievements mostly focused on the field of mathematics. His 'Theory of mathematics' was published in 1811 he started working in the field of magnetism around 1819 Just a few years later, Barlow elected fellow of the Royal Society. He worked on problems associated with magnetic measurements and the issue of deviation in ship compasses caused by iron pieces in the hull. In 1825 he was awarded the Royal Society Copley Medal for his method of correcting the deviation by juxtaposing the compass with a suitably shaped piece of iron used as neutralizing plate. The scientist also began conducting experiments on the influence of rotation upon magnetic and non-magnetic bodies, which was suggested by John Herschel . In the meantime, Barlow already published his second book titled 'New mathematical tables', which soon became well known as 'Barlow's Tables'. In the book, Barlow factors, squares, cubes, square roots, reciprocals and hyperbolic logarithms of all numbers from 1 to 10000. Another major scientific contribution by Peter Barlow the famous Barlow Lens which is understood as a diverging lens which, used in series with other optics in an optical system, increases the effective focal length of an optical system as perceived by all components that are after it in the system. It is mostly used in the field of astronomy has an effect of increasing the magnification of the image. . During his career, Barlow made several contributions to theand published an essay on the strength and stress of timber in 1817. This work was continued after his death by his sons, who also included a biography of their father. . At yovisto, you may enjoy a video lecture by Carolin Crawford on 'Large Telescopes and why we need them'