Dip circle

Dip circle with brass stand, wood and glass casing with door. Three levelling screws, horizontal circle with clamp and attached vernier scale. The vertical circle is in brass, graduated, with two magnifying lenses. Two knurled screws secure the lower casing, and one for moving the 'Y's which lower or raise the needle from the agate bearnings. There is a level and two needles, probably used with this instrument. The circle diameter is 26cm.

The dip circle is by Thomas Charles Robinson, with needles by Henry Barrow and John Dover. It was in use at the Royal Observatory, Greenwich, from January 1843 to October 1861. It is referred to in the published Greenwich magnetical and meteorological observations 1845, 1847 etc., in Greenwich Observations, 1860 and in Derek Howse's volume on Greenwich Observatory (1975), p. 155.

Object Details

ID: AST0760
Collection: Astronomical and navigational instruments
Type: Dip circle
Display location: Not on display
Creator: Robinson, Thomas Charles; Henry Barrow & Co Dover, John Dent, Edward John
Date made: circa 1842
Credit: National Maritime Museum, Greenwich, London
Measurements: Overall: 390 mm x 375 mm x 22 mm
Parts: Dip circle