telescopes

From: Glenn Morton (glenn.morton@btinternet.com)
Date: Thu Jan 24 2002 - 00:01:51 EST

  • Next message: Jonathan Clarke: "Re: telescopes"

    For those who continue to question the observational data available to
    Whewell, they should consider that the Lord Rosse telescope of which he
    spoke was built in 1844 and Lord Rosse used it to view the nebula as
    outlined in a previous post. One source on this telescope said that this
    scope, whose data Whewell rejected, was the largest telescope in existence
    until well into the 20th century:

    "The tube was 57 feet long and up to eight feet in diameter. It was
    suspended between mighty masonry walls 70 feet long, 56 feet high, and 24
    feet apart. The whole instrument was reported to have cost 20,000, a truly
    astronomical sum for an amazing astronomical instrument.

    The telescope was a considerable success, seeing further into space than
    anything which had gone before, and it remained the largest telescope in the
    world from 1845 until well into this century. It attracted as visitors to
    Birr the most eminent scientists and others who wished to experience the
    wonders seen through it. Its most famous discovery was the spiral shape of
    some nebulae - now known to be neighbouring galaxies.

    Within the last few months, the telescope, nicknamed The Leviathan of
    Parsonstown - the Leviathan being a legendary monster, and Parsonstown being
    an old name for Birr - has been restored, and is now a magnificent sight at
    Birr Castle Demesne. It still awaits a new mirror, but this is on the way.
    One of the two original six foot mirrors - the second is lost - is in the
    Science Museum in London - but attempts to get it back have proved
    unsuccessful. Maybe we'll get it back one day.

    William Parsons, Third Earl of Rosse, who received many honours in his day,
    including Presidency of the Royal Society, died from cancer at No.1 Eaton
    Square in Monkstown, Co. Dublin, on October 31, 1867. "
    http://www.gb.nrao.edu/~glangsto/lessons/lessonHISTORY.html

    It was the 100-inch telescope which replaced Lord Rosse's as the largest in
    1918! Thus the majority of the data available to the debaters in the 1920
    about where the nebula lay, consisted of data from telescopes smaller than
    Lord Rosse's. This means that Whewell had at his disposal the knowledge from
    a telescope which was bigger than most telescopes in use today! The Hubble
    has an aperture only slightly larger than Rosse's at 94 inches or 8 feet.

    So please, if we are to criticise my criticism of Whewell's astronomic
    knowledge, understand what he had available to him.



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