Product images of Borda circle
We use a 280gsm fine art paper and premium branded inks to create the perfect reproduction.
Our expertise and use of high-quality materials means that our print colours are independently verified to last between 100 and 200 years.
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Manufactured in the UK
All products are printed in the UK, using the latest digital presses and a giclée printmaking process.
We only use premium branded inks, and colours are independently verified to last between 100 and 200 years.
The repeating circle consists of a circular polished brass frame, with a wooden handle. The index arm carries the index glass and the telescope arm, with the finder arc, is semi-circular and carries the horizon glass. The tangent screws and clamping screws are positioned on the back of both index arms. The instrument has four index shades, three red and one green, and three horizon shades, two red and one green. Index-glass adjustment is made by a screw and on the horizon glasses by capstan screws. Attached to the circle is a magnifier on a hinged 115mm swivelling arm serving both verniers with a frosted glass shade. There is also a threaded telescope bracket with perpendicular adjustment made by a rising-piece and a milled knob. The telescopes, unidentified parts and the box are missing. The instrument has a polished brass limb with an inlaid silver scale from 0 to 720 by 20'. It also has a polished brass finder arc from 180 to 0 to 160 by 1, with two brass stops. The repeating circle has two silver verniers measuring to 20 arcseconds, with the zeros at the right.
- Image reference: F6430-001
- National Maritime Museum, Greenwich, London