astronomy

Solarigraphy

Solarigraphy is a astronomy topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Solarigraphy rather than just read about it. In short: Solarigraphy (or solargraphy) is a concept and a photographic practice based on the observation of the sun path in the sky (different in each place on the Earth) and its effect on the landscape, captured by a specific procedure that combines pinhole photography and digital processing. Invented around 2000, solarigraphy uses photographic paper without chemical processing, a pinhole camera and a scanner to create imag…

Key takeaways

Solarigraphy belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Solarigraphy to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Solarigraphy from memory before moving on to harder problems.

Reference excerpt

Solarigraphy (or solargraphy) is a concept and a photographic practice based on the observation of the sun path in the sky (different in each place on the Earth) and its effect on the landscape, captured by a specific procedure that combines pinhole photography and digital processing. Invented around 2000, solarigraphy uses photographic paper without chemical processing, a pinhole camera and a scanner to create images that catch the daily journey of the sun along the sky with very long exposure times, from several hours to several years. The longest known solarigraph was captured over the course of eight years. Solarigraphy is an extreme case of long-exposure photography.

Beginnings Previous experiments with long exposures on photosensitive papers and with registration of the sun arcs in the sky were done at the end of the 1990s in Poland by the students Paweł Kula, Przemek Jesionek, Marek Noniewicz and Konrad Smołenski and in the 1980s by Dominique Stroobant, respectively. In 2000, Diego López Calvín, Sławomir Decyk and Paweł Kula started a global and synchronized photographic work known as "Solaris Project". This work, which mixes together art and science, is based on the active participation through the Internet of people interested in the apparent movement of the Sun, that is photographed with artisan pinhole cameras loaded with photosensitive material and subjected to very long exposures of time.

Characteristics Solarigraphs are images that show real elements that cannot be seen with the naked eye representing the apparent trajectories of the sun in the sky due to the rotation of the Earth on its axis. They are mostly made with pinhole cameras and very long exposures, from one day to six months between the winter solstice and the summer solstice or vice versa. The images show the different paths of the Sun the observer has according to the respective latitude over the Earth's surface. The cameras are loaded with photosensitive materials (mainly photographic paper in black and white) so that the sunlight produces a direct blackening on the surface. The trajectories of the Sun and the landscape image appear directly on the surface of the paper forming a negative that is digitised and treated with image processing software. These images also provide information about the periods in which the Sun does not appear to be shining as it is hidden by clouds, which provides information about the weather.

Technical basis and procedure

The key to the technique is the nature of photographic paper that darkens by direct light without having to develop it, thus giving the low sensitivity necessary for such long exposures. Although lenses can be used in obtaining solarigraphs with exposure times of a few hours, for longer exposures a pinhole through which the light enters the camera is more convenient. For this purpose home-made pinhole cameras, usually made of using empty drink cans, film canisters or recycled plastic tubes. A photographic paper for black and white is placed inside the container that acts as a camera, and once the camera is fixed in the chosen place, usually pointing east, south or west, the pinhole is uncovered allowing the light to enter until the camera is collected. The image, already visible at that time on the paper, is negative and ephemeral, since the light continues to expose the emulsion if it is shown, so it is necessary to protect the paper from the light and scan it so it can be viewed in a useable format. This second digital part of the process includes inverting the image to make it positive and usually increasing the contrast. Different circumstances make solarigraphs to show different colours depending on the colour of the light and the paper chosen, but also on conditions such as temperature and humidity at different times of impression, in addition to chemical changes in the paper during exposure.

References

External links

Videos about solarigraphy. "Solargraphy", short film documentary. Taro, Gaizka y Zapiór, Maciej, 2014 "En la solarigrafía nada se interpone entre la superficie del sol y el papel". El Faro de Vigo, farodevigo.es, 23 August 23, 2012. Solarigrafia escolhida como Picture of the day, January 21, 2012, by NASA. Solargraphy camera simulation: flat vs cylinder vs hemi-cylinder pinhole cameras. https://vaidasphotos.com/solargraphy https://vaidasphotos.lt/solargrafija/

Illustrations

Worked examples

Example 1 — a first encounter with Solarigraphy

Start with the simplest possible case. Write down what Solarigraphy claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In astronomy, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Solarigraphy before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Solarigraphy ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Solarigraphy

In research: Solarigraphy appears in astronomy research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Solarigraphy in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Solarigraphy is common in secondary-school and first-year university syllabi. It links to neighbouring topics Alternative photographic processes, Astrophotography, Photographic processes, so understanding it makes those chapters shorter.
In everyday life: Look for Solarigraphy outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Solarigraphy in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Solarigraphy means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Solarigraphy out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Solarigraphy in simple terms?

Why does Solarigraphy matter?

Because it connects several astronomy ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Solarigraphy?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Solarigraphy.