Newtonian telescope Newtonian telescope The Newtonian telescope, also called the Newtonian reflector or just the Newtonian, is a type of reflecting telescope invented by the English scientist Sir Isaac Newton (1642–1727), using a concave primary mirror and a flat diagonal secondary mirror. Newton's first reflecting telescope was completed in 1668 and is the earliest known functional reflecting telescope. The Newtonian telescope's simple design makes it very popular with amateur telescope makers. Newton's idea for a reflecting telescope was not new. Galileo Galilei and Giovanni Francesco Sagredo had discussed using a mirror as the image forming objective soon after the invention of the
Hermanos Conde Hermanos Conde Hermanos Conde (Conde Brothers) are luthiers, makers of classical and flamenco guitars. The Conde dynasty was founded in Madrid by Domingo Esteso in 1915. Esteso trained his nephews Faustino and Mariano Conde Sr. Later, the young Julio Conde joined his brothers. Domingo Esteso died in 1937, and after that time the three Conde Brothers continued working for Esteso's widow under the name of "Viuda y Sobrinos de Esteso" (Esteso's Widow and Nephews) until 1960. In the early 1950s, Julio Conde set up a new handicraft guitar center. From 1960 until 1988-89 they took over the shop and called