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Sketches of Saturn from the Letter on Sunspots

Galileo Galilei

Galileo's own small sketches showing how Saturn appeared through his telescopes, from his letter on sunspots.

These sketches are Galileo's own attempt to record Saturn's puzzling appearance through his telescope.

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Scanned page of printed Italian text from Galileo's letter on sunspots. Two small diagrams appear mid-page in the text: one shows Saturn as a shape with two side lobes, and another shows a rounded oval with two small stars at its sides.
Galileo Galilei, sketches of Saturn, from his letter on sunspots.

About this source

What it is

This is a page from Galileo Galilei's printed letter on sunspots, containing two small diagrams of Saturn as he observed it through different lenses.

Why it matters

Saturn's rings were not understood at the time, so Galileo's telescopes showed the planet as an odd shape with side lobes rather than a clear ring. These sketches reveal both the limits of early telescopes and Galileo's effort to record exactly what he saw, even when he could not fully explain it.

Look closer

  • How does Galileo's sketch of Saturn differ from how we now know the planet looks?
  • Why might recording an unclear or strange shape still be valuable to later scientists?
  • What does this tell you about the limits of the instruments Galileo was using?

This painting is part of the curated material that grounds the AI version of Galileo Galilei on Humy.ai — when students ask about related events, the AI can quote it and cite it.

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Title page of the 1610 Latin book Sidereus Nuncius by Galileo Galilei, printed in Venice by Thomas Baglionus. Black text in several type styles, with a central woodcut emblem of a seated figure in an oval frame flanked by cherubs. Handwritten shelfmark appears at the bottom.Book

Primary source

Sidereus Nuncius

Galileo Galilei · 1610

Engraved oval portrait print of a bearded older man with receding hair, wearing a white collar and a buttoned dark coat, in an oval frame. Inscribed 'Galileus Galileus Florentinus' at top, 'Eques Octavius Leonus' and 'Romanus pictor fecit' at bottom, and dated '16 24' with 'Superiorum licentia'. Printed on cream paper with a grayscale color scale at right.Painting

Primary source

Portrait of Galileo Galilei (1624 print)

1624

Oil portrait of an elderly bearded man with a white collar, wearing a black robe, seated at a table with books, a pair of dividers in his raised hand, and a celestial globe to the left, in a dark background. A brass plaque on the frame reads Galileo Galilei.Painting

Primary source

Oil Portrait of Galileo in His Study

Unknown Italian painter · 18th century (?)

Oval-framed line engraving of an older bearded man in a large white collar and dark doublet, with a Latin inscription above reading Galileus Galileus Florentinus, and an artist credit below. Handwritten Italian caption on mount beneath.Painting

Primary source

Galileo Galilei, line engraving by Ottavio Leoni

Ottavio Leoni · 1624

Title page of the 1632 Florentine edition of Galileo Galilei's Dialogo, printed in large serif capitals with a decorative woodcut emblem, imprint 'In Fiorenza, Per Gio: Batista Landini MDCXXXII', and several library stamps and handwritten shelf marks.Book

Primary source

Dialogue Concerning the Two Chief World Systems

Galileo Galilei · 1632

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