Friday, 1 September 2017

William Gilbert - Physician-in-ordinary

Our caveman ancestors painted images of the Moon on cave walls. However, few images have survived, or have been found. The best preserved Neolithic Moon maps have been found in Knowth, Ireland and are nearly 5000 years old. However, it is quite hard to make out the features.

Leonardo da Vinci made a charcoal drawing of the Moon in 1505. The very first Tudor map of the Moon that can be verified was drawn sometime before 1603 by William Gilbert physician-in-ordinary to Queen Elizabeth I. William Gilbert was born in 1540 and died in 1603. We don't know when his map was drawn but it was published posthumously in 1651 in the book De Mondo Nostro Sublunaria Philosophia Nova. 
Gilbert's map was drawn without the aid of a telescope and shows good approximations to the correct positions of the lunar maria but shows no details of any craters.  The map is reproduced below next to  a photo of the Moon taken by myself through a Konus 500 reflecting telescope.
Gilbert's map shows a region called Regio Magna Occidentalis which corresponds to an area occupied by the Sea of Serenity, the Sea of Tranquility and the Sea of Fertility. The small ellipse at East-North-East labelled Britannia is Mare Crisium (the Sea of Crisis). Gilbert's Continens Meridionalis and Insula Longa correspond to parts of Oceaus Procellarum.  Unfortunately Gilbert's map was unkown until 1651 by which time Galileo's Starry Messenger had provided a detailed examination of the lunar surface with a 30X telescope. However, Gilbert's map is interesting as it clearly shows what details on the lunar surface could be viewed in Tudor times with the naked eye.

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