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Slide rule
Slide rule for calculating level errors. Slider marked "POSITIVE" "NEGATIVE". On either side of the slider are the fixed pieces. One is marked "ABOVE THE POLE" and then on another part of the same piece it is marked "SCALE OF CORRECTIONS OF TRANSITS IN SECONDS OF TIME FOR LEVEL ERROR IN SECONDS OF ARC LATITUDE 51 degress 28' 39'' NORTH". The other fixed piece is marked "BELOW THE POLE" and elsewhere on the same piece, 'STARS NPD BELOW THE POLE". The back of this slide rule is blank.
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Object Details
| ID: | ZBA0636 |
|---|---|
| Type: | Slide rule |
| Display location: | Not on display |
| Creator: | Troughton & Simms |
| Date made: | circa 1850 |
| People: | Troughton & Simms; Royal Greenwich Observatory Airy, George Biddell |
| Credit: | National Maritime Museum, Greenwich, London |
| Measurements: | Overall: 8 mm x 620 mm x 153 mm |