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Partial solar eclipse 2026 LIVE
Join the Royal Observatory Greenwich live online to watch the 90% partial solar eclipse visible from the UK
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Cutty Sark Rig Climb
Experience life at sea and climb the rigging of one of London's true icons
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Astronomers Take Over
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How to see the 12 August 2026 partial solar eclipse
Learn more about the best solar eclipse visible from the UK and Ireland so far this century, when around 90-96% of the Sun will be covered by the Moon
ZWO Astronomy Photographer of the Year 2026 shortlist
Discover a selection of the breathtaking images shortlisted in the global astrophotography competition
Making Waves: Dr Dawn Wright
Oceanographer and chief scientist Dr Dawn Wright on diving to the deepest part of the ocean – and why we need to stand up for our blue planet
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Calder, Robert
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1793
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1793
1795
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Admiral John Markham correspondence; letters from Robert Calder (Manuscript)
1793-1795
MRK/100/6
Robert Calder, Chatham, to Sir Henry Martin, Comptroller, with his thoughts on improvements to HM Ships, after Lord Howe saw the French ships outcarry all our ships, on the shape of the hull, the placement of the guns, the length of masts, stowage of ballast, the state of the rigging. (Manuscript)
1793
MRK/100/6/1
Admiral John Markham correspondence; letters from Robert Calder on French warships. (Manuscript)
1793-1795
MRK/100/6/1-3
Robert Calder to Sir Henry Martin, Comptroller, with recommendations on the top masts, on his alterations to the top gallant shrouds of the Theseus, on erecting a wheel in his cabin suspended from the beams of the poop deck to steer the ship, fitted with an iron tiller, for which the officers of the Theseus have signed their support. (Manuscript)
1793
MRK/100/6/3
Robert Calder, London, to Sir Henry Martin, Comptroller, with further thoughts on HM Ships yards, on reefing points, gaff rigging, and sails to improve speed and pointing to the wind, on sheaves and blocks, is willing to make a trial of his ideas. (Manuscript)
1793
MRK/100/6/2
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