Will the Real “First Moon Mapper” Please Stand Up?

Building on the Hubble-Slipher smackdown from last week, a group of historians at the Royal Astronomical Society in the U.K. is aiming to give credit where it’s due to the man who drew the first maps of the moon using a telescope.

Popular thought pegs Italian scientist Galileo Galilei with this feat—in fact, the International Year of Astronomy is built around Galileo’s first use of a telescope to peer into the heavens 400 years ago.

Galileo produced and published a series of drawings based on his observations, including maps of mountains and craters on the moon, the phases of Venus, and the four large moons he could see orbiting Jupiter [the gas giant actually has more than 60 moons, but only four were visible using 1600s technology].

The key part of the above statement is the word “published.” Historically, if you get your work on the record first, you get the glory.

The trouble is that an English mathematician named Thomas Harriot also made detailed maps of the moon using a telescope several months *before* Galileo.


—Image copyright Lord Egremont/RAS

This only makes sense, when you consider that the first functioning telescopes surfaced in the Netherlands in 1608, and within months the devices were for sale in shops across Europe.

Galileo took some time to make his own higher powered versions, which he turned toward the skies in the fall of 1609. Harriot beat him to the punch by creating a telescopic moon map in July of 1609.

I find it hard to believe that—among the myriad science enthusiasts of the era—plenty more people didn’t quickly get over peeking through their neighbors’ windows and decided to aim their shiny new “three-powered spyglasses” at the moon and the stars.

But maybe I’m too naïve.

In any case, there is hard evidence that Harriot had the idea and followed up on it before Galileo. He was either too modest or too complacent to make a big splash with his work.


A purported portrait of Harriot circa 1602

—Image courtesy Max Alexander / Trinity College / Science Photo Library, copyright Trinity College

After all, Harriot had some pretty nice digs in London and the generous patronage of a wealthy English earl. Galileo, meanwhile, was a struggling professor at the University of Padua seeking to gain a better job and the attention of possible funding sources. You do the math.

This isn’t to say Galileo is undeserving. Like many natural philosophers before and after, Harriot drew nice pictures that mimicked the world as he saw it.

Galileo did more than sketch, he drew conclusions that would reverberate throughout human history—lunar mountains and spots on the sun show that the heavens are not perfect, as religion dictated at the time; Earth is not the center of the solar system; the Milky Way isn’t a diffuse band of clouds but a dense collection of stars.

Ultimately, it seems the point isn’t always to be first to see something, but to be first in seeing the implications. So Harriot, we salute you for your maps, and Galileo, we celebrate you for your vision.