Gunter Quadrant

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Object Details

Description: This brass Gunter-type horary quadrant has one brass sight on the top of the quadrant along one radius. There is no pinhole in this sight; it is completely solid. It appears that there was never a second sight. The plumb-bob and string which belong at the vertex are missing. The quadrant contains a geometric square marked from 10 to 50 to 10 in units of one degree, an hour arc (U-shaped) from I to VI to XI to XII and an azimuth arc from 30 to 90 to 120 by ten degrees, an ecliptic arc calibrated by zodiac symbol, a declination scale to 24 degrees, a horizon arc marked from 10 to 30, a second hour arc marked from VIII to I, a calendar arch lettered by month, and a circumference marked from 0 to 90 in units of one-half degree. There are suns between most Roman numerals on the hour arcs, moons on each side of the calendar arch, and sets of three dots at each 5-degree mark on the circumference. Five stars are charted: VH, BE, LH, A, PW. This dial was made for a latitude of approximately 52 degrees. There is no instrument maker with initials T. D. who worked around 1790 in Clifton, or in the inventory of the National Maritime Museum, Greenwich.; References:; Gloria Clifton, Directory of British Scientific Instrument Makers..., Greenwich: National Maritime Museum, 1995.; An Inventory of the Navigation and Astronomy Collections in the National Maritime Musuem, Greenwich, National Maritime Museum.
Location: Currently not on view

1790

Physical Description: brass (overall materials)
Measurements: overall: .6 cm x 12.5 cm x 12.5 cm; 1/4 in x 4 15/16 in x 4 15/16 in

National Museum of American History

GUID (Link to Original Record): http://n2t.net/ark:/65665/ng49ca746a5-0aea-704b-e053-15f76fa0b4fa