26th July 1609 Thomas Harriot
http://www-history.mcs.st-andrews.ac.uk/Biographies/Harriot.html
His astronomy brought back to the fore, Harriot went on to make the earliest telescopic observations in England. On 26 July 1609 at 9 p.m. he sketched the Moon which was at that time 5 days old, viewing it through a telescope with a magnification of 6. He sketched the Moon again a year later on 17 July 1610, by this time he had a telescope giving him a magnification of 10. Soon he had constructed a telescope with a magnification of 20, then by April 1611 he had a 32 magnification telescope.
(Galileo Galile started recording his observations of the heavens in the autumn of 1609)
Ah, but Galileo told people about it 😉
Very true and a sad loss to science, as follows;
http://www-groups.dcs.st-and.ac.uk/~history/HistTopics/Harriot.html
Quote:-
"Thomas Harriot died in 1621. He had published no mathematical or astronomical works during his lifetime, but he left his papers in reasonably good order and set out his wishes in his will that they should be properly edited and published. This article tells the story of how 380 years have passed since Harriot's death yet, despite many attempts, his dying wishes have not yet been properly carried out."