POWERHOUSE COLLECTION

McClean spectroscope in case

Object No. H10031

Spectroscopes are devices that take the light emitted from objects and split it up into their component colours. Every element has a different signature spectrum, and thus the spectroscope allows the observer to identify what elements the object is composed of. Spectroscopy was first used in astronomy in the early 1860s. One of its first uses was to determine the elements that comprise the Sun. Star spectroscopes allow a user to determine the composition of a celestial object, its motion, density, and temperature. This particular type of spectroscope is called a McClean's Star spectroscope. Frank McClean (1837-1904) was a British civil engineer and amateur astronomer. On his retirement, he became dedicated to the science of astronomy, building an observatory in his home. He devoted himself to improving the astronomical spectroscope. Existing star spectroscopes, at the time, required the image of the star to be lined up in the very small 'slit' in the device. McClean developed a spectroscope that did not use a small 'slit' but a concave cylindrical lens that brought the lines of the spectrum to a focus on the retina. Its easy-to-use form meant that once a star was lined up with a telescope, the eyepiece could be removed and the spectroscope inserted. This allowed the device to be used on a wider range of telescopes, and it became instantly popular with amateur and professional astronomers. Frank McClean received the Gold medal from the Royal Astronomical Society in 1899 for his work in systematically surveying the spectra of the Northern and Southern stars. This particular Watson & Sons spectroscope was used in conjunction with Sydney Observatory's 6 inch telescope, H9887. This 6-inch refracting telescope was made by Sir Howard Grubb of Dublin and was used in the North Dome of the Observatory and was thus probably used by Lawrence Hargrave. This spectroscope remains of national significance due to its pioneering role in Australian science and its association with Australia's earliest astronomers and astronomical equipment. It is also of international significance due to its association with nineteenth century scientific instruments and their makers. Reference: Glass, I. S., Victorian Telescope Makers; the Lives and Letters of Thomas and Howard Grubb, Institute of Physics Publishing, Bristol and Philadelphia, 1997 Faed-Muybridge, Dictionary of National Biography, Vol 2, 2001, pg 505. John Browning, How to Work with the Spectroscope, W Johnson printers, London, 1882, pg 26-28 Written by Erika Dicker Assistant Curator, February 2008.