{"product_id":"mural-quadrant-l2157-005","title":"Mural quadrant","description":"This 8ft Mural Quadrant was made for the second Astronomer Royal, Edmond Halley by (or under the direction of) instrument maker George Graham and was such a success that it became a prototype for similar instruments all over Europe.\u003cbr\u003e\u003cbr\u003eA mural quadrant is, as the name would suggest, a telescope mounted on a quarter circle frame which is then mounted on a wall aligned north-south so that the two sides or radii run vertical and horizontal.  The telescope is pivoted at what would be the centre of the circle while the circle's circumference carries a scale from 0 to 90 degrees. This allows the observer to measure the angular height of the star he or she is observing.\u003cbr\u003e\u003cbr\u003eTelescope: The tube length is 8ft with an 8ft 0.5inch focus. Its object glass was replaced in 1789 replacing the common OG with an achromatic one.\u003cbr\u003e\u003cbr\u003eMount: The mount is made up of an iron and mahogany frame with a brass scale divided into 96 parts by subdivision which could then be readjusted to produce a 0-90 degree angle scale. The scale was redivided by John Bird in 1753 and the quadrant remounted to face north instead of south.\u003cbr\u003eGeorge Graham\u003cbr\u003e\u003cbr\u003eOriginal size: 2438 mm","brand":"prodigi","offers":[{"title":"Fine art poster \/ XS: 30 x 20cm \/ none","offer_id":57027669361022,"sku":"GLOBAL-FAP-8X12","price":22.95,"currency_code":"GBP","in_stock":true},{"title":"Fine art poster \/ S: 45 x 30cm \/ none","offer_id":57027669393790,"sku":"GLOBAL-FAP-12X18","price":28.95,"currency_code":"GBP","in_stock":true},{"title":"Fine art poster \/ M: 60 x 40cm \/ none","offer_id":57027669426558,"sku":"GLOBAL-FAP-16X24","price":38.95,"currency_code":"GBP","in_stock":true},{"title":"Fine art poster \/ L: 75 x 50cm \/ none","offer_id":57027669459326,"sku":"GLOBAL-FAP-20X30","price":54.95,"currency_code":"GBP","in_stock":true},{"title":"Fine art poster \/ XL: 90 x 60cm \/ none","offer_id":57027669492094,"sku":"GLOBAL-FAP-24X36","price":69.95,"currency_code":"GBP","in_stock":true},{"title":"Fine art poster \/ XXL: 150 x 100cm \/ none","offer_id":57027669524862,"sku":"GLOBAL-FAP-40X60","price":82.95,"currency_code":"GBP","in_stock":true},{"title":"Framed picture \/ XS: 40 x 30cm \/ none","offer_id":57027669557630,"sku":"MUS-CFPM-12X16","price":59.95,"currency_code":"GBP","in_stock":true},{"title":"Framed picture \/ S: 60 x 45cm \/ none","offer_id":57027669590398,"sku":"MUS-CFPM-18X24","price":79.95,"currency_code":"GBP","in_stock":true},{"title":"Framed picture \/ M: 75 x 50cm \/ none","offer_id":57027669623166,"sku":"MUS-CFPM-20X30","price":119.95,"currency_code":"GBP","in_stock":true},{"title":"Framed picture \/ L: 90 x 60cm \/ none","offer_id":57027669655934,"sku":"MUS-CFPM-24X36","price":159.95,"currency_code":"GBP","in_stock":true},{"title":"Framed picture \/ XL: 100 x 70cm \/ none","offer_id":1851143094316,"sku":"MUS-CFPM-28X40","price":204.95,"currency_code":"GBP","in_stock":true},{"title":"Postcard \/ Standard: 6 x 4in \/ Single","offer_id":57027669688702,"sku":"GLOBAL-POST-MOH-6X4","price":1.95,"currency_code":"GBP","in_stock":true},{"title":"Postcard \/ Standard: 6 x 4in \/ 10-pack","offer_id":57027669721470,"sku":"GLOBAL-POST-MOH-6X4-10","price":14.95,"currency_code":"GBP","in_stock":true},{"title":"Postcard \/ Standard: 6 x 4in \/ 20-pack","offer_id":57027669754238,"sku":"GLOBAL-POST-MOH-6X4-20","price":24.95,"currency_code":"GBP","in_stock":true},{"title":"Postcard \/ Large: 7 x 5in \/ Single","offer_id":57027669787006,"sku":"GLOBAL-POST-MOH-7X5","price":2.95,"currency_code":"GBP","in_stock":true},{"title":"Postcard \/ Large: 7 x 5in \/ 10-pack","offer_id":57027669819774,"sku":"GLOBAL-POST-MOH-7X5-10","price":19.95,"currency_code":"GBP","in_stock":true},{"title":"Postcard \/ Large: 7 x 5in \/ 20-pack","offer_id":57027669852542,"sku":"GLOBAL-POST-MOH-7X5-20","price":29.95,"currency_code":"GBP","in_stock":true},{"title":"Greetings card \/ Standard: 6 x 4in \/ Single","offer_id":57027669885310,"sku":"GLOBAL-GRE-MOH-6X4-BLA","price":2.5,"currency_code":"GBP","in_stock":true},{"title":"Greetings card \/ Standard: 6 x 4in \/ 10-pack","offer_id":57027669918078,"sku":"GLOBAL-GRE-MOH-6X4-BLA-10","price":15.95,"currency_code":"GBP","in_stock":true},{"title":"Greetings card \/ Standard: 6 x 4in \/ 20-pack","offer_id":57027669950846,"sku":"GLOBAL-GRE-MOH-6X4-BLA-20","price":26.95,"currency_code":"GBP","in_stock":true},{"title":"Greetings card \/ Large: 7 x 5in \/ Single","offer_id":57027669983614,"sku":"GLOBAL-GRE-MOH-7X5-BLA","price":3.5,"currency_code":"GBP","in_stock":true},{"title":"Greetings card \/ Large: 7 x 5in \/ 10-pack","offer_id":57027670016382,"sku":"GLOBAL-GRE-MOH-7X5-BLA-10","price":19.95,"currency_code":"GBP","in_stock":true},{"title":"Greetings card \/ Large: 7 x 5in \/ 20-pack","offer_id":57027670049150,"sku":"GLOBAL-GRE-MOH-7X5-BLA-20","price":33.95,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/2785\/2654\/files\/l2157-005.jpg?v=1772715918","url":"https:\/\/prints.rmg.co.uk\/products\/mural-quadrant-l2157-005","provider":"Royal Museums Greenwich prints","version":"1.0","type":"link"}