» Dent Dipleidoscope (0555)

Immagini

DESCRIPTION

The dipleidoscope, an instrument for determining the local midday within a few seconds, was invented by James Bloxan and patented by Edward Dent, the builder of the Westminster clock, in 1843. It consists of a prism formed by two mirrors and a glass plate mounted on a solid brass base that can be leveled by adjusting the screwable legs. In operation, one observes two images of the sun, one from the glass plate reflection and one from the internal prism reflection. These two images come closer together until they are superposed at midday. The glass plate is darkened to attenuate the sun's brightness.

ISCRIZIONI

Il coperchio del prisma porta la scritta: "Dipleidoscope Breveté de M.^r Dent".

BIBLIOGRAPHY

[1] Stott, C. ; Hughes, D. W.; "The Amateur's Small Transit Instrument of the 19th Century", The Quarterly Journal of the Royal Astronomical Society, Vol. 28, 1987. Pagg. 30 -- 41;
[2] URL [ http://adsabs.harvard.edu/full/1987QJRAS..28...30S ]
[3] Stong, C. L.; "Simple Ways to Calculate the Orbits of Space Vehicles", Scientific American, January 1969, Volume 220, Number 1; pagg. 123 - 126, 128.;
[4] G.B. Amici Nuovo Cimento tomo I pg 44 50 , 1855

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