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By Alison Boyle on

Last Chance To See: Thomas Harriot

Monday marked 401 years since Thomas Harriot made the first recorded astronomical observation with a telescope – so one year since we opened our Cosmos & Culture exhibition celebrating Harriot and other astronomers.

For the last year, we’ve been lucky enough to have some of Harriot’s drawings on display, but for their long-term preservation it’s time to remove them from the light. This weekend is your last chance to see the centuries-old originals before we return them to their owner’s care and replace them with facsimiles.

Harriot’s first drawing of our Moon pre-dates any other telescopic observations. But Galileo beat him to it in discovering moons around Jupiter. Harriot probably read Galileo’s Sidereus Nuncius around July, but by then Jupiter was too near the Sun for him to check it out. This drawing shows his first observations of the moons in autumn 1610. The first night wasn’t too successful – he noted, ‘I saw but one, and that above’ – but over the next year he made 98 further observations and tracked all four Galilean satellites.

Harriot tracks the Galilean satellites (Lord Egremont/West Sussex Record Office, used with permission)

By winter Harriot had turned his telescope on the Sun, risking blindness by viewing it directly with only mist to shield its fierce glare. In December 1610 he saw sunspots – one of several astronomers to independently discover them around the same time.

Harriot notes 'three blacke spots' on the Sun (Lord Egremont / West Sussex Record Office, used with permisson).

So with all these achievements, why isn’t Harriot as famous as Galileo? Well, unlike his Italian counterpart he already had rich patrons, so didn’t need to publish his work to attract sponsors. He may have also preferred to keep a low profile after a brief stint in prison as a Gunpowder Plot suspect. After his death, his astronomical papers lay undiscovered for over 150 years, so not many people have seen them in the last four centuries. If you’re in London this week, take a good look while you still can.