Kepler's Panoramic Drawing Device

Figure KCO.1 – Kepler's Camera Obscura ca. 1620
This is Kepler's device as re-imagined by Rod Bantjes   Photo © Rod Bantjes.

Figure KCO.2 – Zahn's Camera Obscura ca. 1685
Source: Zahn, Joannes. Oculus Artificialis Teledioptricus, Sive Telescopium Würzburg: Herbipoli, 1685.

1.0 Uniqueness of Kepler's Design

When I first read Sir Henry Wotton's description of Kepler's rotating camera obscura, I knew it was something radically different from any other camera obscura in his time and since. I had to build one to transform what for many might be an obscure verbal description into something real, and to explore the implications of this remarkable artefact for Kepler's thinking about how visual perception works. As far as I have been able to tell, my device is the first that the world has seen for 400 years.

 

1.1 Overhead Lens: Kepler has placed the camera lens above the user's head so that it projects its image downwards onto the image-plate.^[xxx] This design was not common until the 19^th century when tent-style camera obscuras were widely used as aids in landscape drawing. Camera obscuras in Kepler's time, like Zahn's depicted in Figure KCO.2, had the lens in front pointing towards the scene. Kepler's lens pointed directly upwards and would have projected an image of the sky were it not for an angled mirror above it to reflect light from the horizon down into the device. In order for the image to be upright, the mirror must be directed to the scene behind the observer.

 

1.2 Rotation: Zahn's device is designed for fixed viewing. Kepler's is designed to pivot around a central axis as though one were turning one's head for an all-round view. As Kepler's camera turns, the mirror sweeps round and reflects a changing scene down onto the image plate – a full 360° panorama.

 

In the 19^th century, numerous rooftop panoramic camera obscura were built – such as the ones in Eger, Hungary, Lisbon castle and Grahamstown in South Africa. But in these devices only the optical head turns while the image-plate and platform on which the observers stand remain fixed. As the panoramic image scrolls across the image-plate it also rotates so that it sometimes appears upside down or sideways to the viewer. In Kepler's design, the entire device rotates so that from the individual observer's perspective, the panoramic image scrolls across the image-plate right-side up. This whole-device rotation makes Kepler's design entirely unique.

 

1.3 Image-Scroll: Instead of a single sheet of paper for tracing the projected image, Kepler's device has a continuous roll of paper. The tent-style camera obscuras of the 19^th century were used to draw conventional rectangular landscapes from a single point and direction of view. Kepler used his to create a long, narrow image which records a constantly changing angle of view. My version of the device produces an image 1 foot high and about 7 feet long. This paper-scroll for recording a panoramic image is the second feature that makes Kepler's camera absolutely unique.

Figure KCO.3 – Brahe Quadrant and Celestial Sphere, 1602
Source: Brahe, Tycho. Tychonis Brahe Astronomiae Instauratae Mechanica. Noribergae,: Apud L. Hvlsivm, 1602.

 

1.4 What was Kepler Thinking?: Why was Kepler dissatisfied with the fixed camera obscuras of his time and what was he trying to achieve with this radically different design? As an astronomer, Kepler needed to observe very distant objects with great precision. Because any amount of distortion caused by their instruments or their eyes would compromise this accuracy, early astronomers had to concern themselves with how observational instruments, including the eye, worked. Jonathon Crary is right that for early thinkers the camera obscura was a model of the eye, and its effects were thought to give insights into how we see. Kepler was an influential theorist of perception, and in building the camera obscura he was no doubt trying out new ideas about how perception worked.

 

Thinking through artefacts is a dialectical process. We start with a new idea that we want to test by creating a working model. In this move our idea becomes built into the model. By trying out and exploring the properties of the artefact, we better understand the original idea, its limitations and possibilities, and are able to build upon it with better ideas. Thinking unfolds in two parts: 1) in the head, prior to the artefact, and 2) in interaction with the artefact. We can't get inside Kepler's head, but we can interact with his artefact-of-thought and in this way gain insight into his thinking process.

Figure KCO.4 – Lanci's Panoramic Drawing Machine, ca. 1583
Source: Liedtke, Walter A. “The 'View in Delft' by Carel Fabritius.” Burlington magazine 118, no. 875 (1976): 61-73.

2.0 Design of the Device

All I had to go on in designing this device was the following description written by Sir Henry Wotton of his visit to Kepler in 1620:

	He hath a little black tent … which he can suddenly set up where he will in a field, and it is convertible (like a windmill) to all quarters at pleasure, …[it has a biconvex lens from a telescope] through which the visible radiations of all the objects without are intromitted, falling on a paper, which is accommodated to receive them; and so he traceth them with his pen in their natural appearance, turning his little tent round by degrees, till he hath designed the whole aspect of the field.[xxx]

 

2.1 Windmill: Wotton describes this oddity by comparison to three known things: a tent, a telescope and a windmill. In this period, the entire machinery of a windmill rotated on a platform so that it could be turned to follow the changing direction of the wind (first image in Figure KCO.5). My first design idea was much more like a windmill, where the observer sat inside upon a revolving platform. Perhaps this was how Kepler's was designed, but that would have been too heavy for me since I hoped to carry it in my checked baggage to Europe and South Africa. Instead, mine rotates on top of a surveyor's tripod so that the user must move as she rotates it.

 

2.2 Tent: You can see from the illustration (KCO.1) that I have retained the idea of the tent. So mine looks rather like a 19^th-century tent-style landscape drawing machine (second image in Figure KCO.5), except taller since the user must stand.

 

2.3 Armillary Sphere: I took inspiration from other devices from Kepler's time whose purpose was to record the locations of things in space. The quadrant in figure KCO.3 is from Tycho Brahe's book on astronomical instruments that Kepler would have been very familiar with. I have depicted it here next to Baldassare Lanci's panoramic drawing device (Figure KCO.4) to show the similarities between them.

 

They each have a sighting rod (an alidade) (TS in the depiction of the quadrant and TE for the drawing machine) that can be used to locate things in space. The sight swings round (360° in the quadrant and 180° in the drawing machine) and up (90° and ~45°). These devices, like Kepler's camera obscura, model seeing and measuring the world-in-the-round from a central pivot. Spatial positions are recorded in writing (in degrees of arc) in the case of the quadrant and they are recorded by drawing on a sheet of paper in case of the the drawing machine.

 

The armillary sphere (third device from left in Figure KCO.5) is a fully spherical version of this idea of seeing-in-the-round from a central point. Tycho Brahe's celestical globe (Figure KCO.3) is a spherical depiction of what one sees when one charts the heavens with an armillary sphere. I am certain that this way of seeing, thoroughly familiar to astronomers in his time, was an influence on Kepler's thinking when he imagined the rotating camera obscura. So I have designed the body of my reimagined version on the inspiration of the armillary sphere.

Figure KCO.5 – Design Equation: Windmill + Tent Camera Obscura + Armillary Sphere = Rotating Camera Obscura

3.0 Using the Device

4.0 What was Kepler Thinking?

 

4.1 Spherical Visual Field:

 

4.2 Bodily Motion:

 

4.3 Time and Memory:

 

Footnotes:

 

References: