and housed in the original observatory was the largest and most technologically advanced telescope in NSW from the late 1930s when it was completed up until the mid 1960s when the 24 inch and 40 inch telescopes were constructed and installed at Siding Spring Observatory. This telescope with its observatory dome was one of the first in Australia to incorporate electric motors to operate the telescope and dome. The intact complex complete with observatory, instruments, working design drawings, machinery, jigs, documentary archive is likely to be of State heritage significance as a rich research resource with the ability to provide insight into many aspects of the field of astronomy and the history of its development in NSW. Linden Observatory Complex was listed on the New South Wales State Heritage Register on 5 March 2010 having satisfied the following criteria. The place is important in demonstrating the course, or pattern, of cultural or natural history in New South Wales. The Linden Observatory is of State heritage significance for its historic values. Ken Beames' 24" telescope housed in the custom built observatory was important in the history of telescope making in Australia and NSW as it was the largest Australian made telescope in NSW from the time of its construction in the late 1930s until the 1960s when the 40 inch and 24 inch telescopes at Siding Spring Observatory were designed and constructed. Beames' 24 inch telescope is regarded as one of the most significant amateur built instruments in Australia at the time it was built, and remains so to this day. While amateur instruments of this aperture are becoming more common, instruments of this size with professional standard mounting and drives are not. . The observatory where Beames made his telescopes and other instruments and optics associated with the strudy of astronomy is tangible evidence of the ongoing, strong and productive relationship between the amateur and professional in the field of astronomy from the late 19th century through the 20th century. The historic significance of the 24 inch telescope is increased by the fact that it was made by one of the very few Australian telescope makers working in Australia at the time. Not withstanding the uniqueness of his telescope making activities Beames was a prolific producer of telescopes producing around 450 instruments ranging from 6 inch telescopes through to the 24 inch telescopes . The 24 inch telescope was also