who was the second?
Astronomer and composer of music.
William Herschel
Frederick William Herschel (; ; 15 November 1738 – 25 August 1822) was a German-born British astronomer and composer of music. 
how many globular clusters are in the milky way About 150 to 158 currently known what are these? It is a spherical collection of stars that orbits a galactic core. do they contain metal? It consists of Population II stars, to which astronomers refer to as heavier elements as metals and to the proportions of these elements as the metallicity. how the last term calculated? Astronomers use several different methods to describe and approximate metal abundances, depending on the available tools and the object of interest. who were among the observers of this collection of stars? Abraham Ihle and William Herschel.
wiki:19645860
William Herschel [SEP] Introduction
Herschel pioneered the use of astronomical spectrophotometry, using prisms and temperature measuring equipment to measure the wavelength distribution of stellar spectra. In the course of these investigations, Herschel discovered infrared radiation. Other work included an improved determination of the rotation period of Mars, the discovery that the Martian polar caps vary seasonally, the discovery of Titania and Oberon (moons of Uranus) and Enceladus and Mimas (moons of Saturn). Herschel was made a Knight of the Royal Guelphic Order in 1816. He was the first President of the Royal Astronomical Society when it was founded in 1820. He died in August 1822, and his work was continued by his only son, John Herschel.