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The Altitude and Azimuth Instrument


Edinburgh's Altitude and Azimuth Instrument

Edinburgh's Altitude and Azimuth Instrument

One of the main instruments purchased by the Astronomical Institution of Edinburgh for their Observatory was an Altitude and Azimuth (AltAz) device. It is not clear why this instrument was purchased bearing in mind that they were purchasing a superior resolution Transit Instrument and a Mural Circle with which to measure celestial Right Ascension and Declination with supreme accuracy.

The instrument, made by Troughton & Simms in London, cost £432/15/- and was delivered and installed in October 1830. It occupied a position in the Dome of the Observatory from which it would ultimately be necessary to remove it to make way for an Equatorial Telescope - which was not on the original purchasing list of the Institution.

This instrument was never "used in anger" and there was an unsuccessful attempt to sell it at a later date. It is currently in storage in Edinburgh.

Whilst not being used for a specific purpose, Thomas Henderson did check it out and he made a sequence of Azimuth measurements of the Edinburgh skyline which we reproduce in the following image.

Edinburgh's Skyline by Azimuth

Edinburgh's skyline by Azimuth from the Calton Hill Observatory - 1830's