Features:

  1. This is where backyard astronomy ends up if you let it get out of hand.

  2. The Leviathan was built by William Parsons, Lord Rosse, formally 3rd Earl of Rosse (1800-1867)---but I don't think that is Himself on the platform (see Wikipedia: Hiberno-English: Reflection for emphasis: Himself).

  3. It was located at Birr Castle (Lord Rosse's estate) in Birr (formerly Parsonstown), County Offaly, Ireland.

  4. The Leviathan was a reflector with primary mirror of diameter 1.83 meters (72 inches or 6 feet) made of speculum with a mass of nearly 4 metric tons. It took 5 attempts in 3 years (1842--1845) to construct the primary mirror (see Wikipdia: Leviathan of Parsonstown: Construction and Design).

    Speculum is an alloy of copper and tin with a dash of arsenic---which gives it that extra kick---invented for reflector telescope mirrors by Isaac Newton (1643--1727).

    It is brittle, tarnishes easily, and reflects only about 16 % of incident visible light.

    By the later 19th century, reflector primary mirror were made of glass (eventually borosilicate glass: see Wikipedia: Borosilicate glass: optics) with a thin reflective coating first of silver and later of aluminum (see Wikipedia: History of the telescope. No more speculum.

  5. The Leviathan could be slewed through a fairly large range in altitude (maybe 10°--170°???), but only ∼ 15° in azimuth centered on the meridian (see Wikipdia: Leviathan of Parsonstown: Construction and Design).

    The telescope mount was an altazimuth mount with such limited range in azimuth that was close to a transit mount (see Wikipedia: Leviathan of Parsonstown: Side note).

    Astronomical objects could be observed for about an hour centered on their transits of the meridian.

  6. The Leviathan's poor telescope mounting and the cloudy-rainy climate of Ireland greatly limited the utility of the Leviathan, but it was a magnificent cryptid.

  7. The Leviathan was dismantled in 1914. A modern Leviathan reconstruction was build in 1996--1999.

  8. The Leviathan's greatest discovery was the spiral nature of the spiral nebulae which we now call spiral galaxies (see Wikipedia: Leviathan of Parsonstown: Operation).

    The discovery 'twas by Himself, Lord Rosse, in 1845.

  9. The Danish-Irish astronomer J.L.E. Dreyer (1852--1926) began his compilation New General Catalogue (NGC) deep-sky objects (most notably galaxies) using the Leviathan in the period 1874---1878.

  10. See the Leviathan / Lord Rosse (1800--1867) videos below (local link / general link: telescope_leviathan_lord_rosse_videos.html).

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