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30 October 2024
Accessible Content in Astronomy: Period Folding
Kate Meredith GLAS Education
Maire Lucero
GLAS Education
Chris Schultz
GLAS Education
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Gazing at a clear night sky, the stars, constellations, and faint galaxies are mysterious and magnificent. Many scientists observe these picturesque details and seek to analyze their patterns using many data analysis techniques, such as period folding. Generally, period folding involves stacking data gathered over many observing runs to reveal a complete cycle. It assumes the data follow an oscillating or periodic pattern. A common explanation of period folding is the process of horizontally dividing a scatterplot wave into segments as long as the period of the wave and stacking these segments together to compile one complete, continuous wave. The mathematics of period folding is complex, so verbal descriptions are used to introduce the concept. Even a clear verbal explanation of period folding is difficult to construct, so many educators use visual aids. However, visualizations are not accessible to low-vision students. How does a professor provide the same visual examples when teaching period folding without relying on a visual aid?
Geneva Lakes Astrophysics and STEAM (GLAS) has been working with the University of North Carolina at Chapel Hill for the past four years to improve the accessibility of the Our Place in Space (OPIS!) curriculum. In the summer of 2023, GLAS staff and interns set out to design an audio-based and visually accessible video explaining period folding. The GLAS video is based on the OPIS! "What is Period Folding?" by Aaron LaCluze of Central Michigan University. It is available on the Skynet University YouTube channel.
Image: A series of data points that form a wave with two peaks and one full trough is shown in high contrast. A vertical line intersecting the curve at the beginning of the second cycle shows the location of the sonification that is being played.
The new version of the video uses several techniques to improve accessibility. One technique is data sonification, the process by which data is represented by nonverbal audio to communicate graphical information. In the period-folding video, high pitches represent higher brightness values, and the sound follows the graph from left to right. The sonification files provide the same examples as a visual aid while providing a low-vision-accessible explanation of period folding.
The team lead on this project included the GLAS president and director of education, Kate Meredith. The process began by dissecting the definition and process of period folding. It was important for the team to fully master the concept before creating the video to provide a concise yet thorough explanation. Simultaneously, they highlighted vital accessibility features. During the planning process, Shiloh Miller, a summer intern from the University of Chicago, wrote a script for the video, ensuring that all visuals had an audible explanation. After compiling the information, the team began creating the visual content.
Next, two interns, Maire Lucero and Sofiia Lauten, developed the sonification. Maire is an intern and student from Badger High School in Lake Geneva, Wisconsin, and Sofiia is an intern from the University of Wisconsin Madison. The sonification was created using the Python package Astronify, which was developed by the Space Telescope Science Institute (STScI) server years ago. After the two interns programmed the audio files, they were imported into GarageBand to improve the acoustics. The ideal timbre for sonification is simple and acoustically pleasing, so the audio is enjoyable but not distracting. The notes should also be quick to explicitly differentiate data points. Sonification is not only a science, but it is also an art incorporating musical knowledge of pitch and sound design.
Meanwhile, Shiloh designed the visuals and animations of the video. With coaching from Jen Kotler, a UX designer from STScI, she precisely designed simple visuals to reduce distractions for the viewer, and she used a high-contrast color palette, so the animations were visible to partially blind viewers. The intern effectively incorporated accessible elements to create an aesthetically pleasing video with smooth animations.
The final step of the project was to record the script. Maire provided the vocals while Shiloh managed the sound controls. The pair retreated to a small storage closet to record the vocals to reduce any external noise. After the video components were compiled, a low-vision GLAS employee tested the product. Our current product includes edits based on the employee’s recommendations.
During the video creation process, the team developed an innovative framework for designing accessible content. The goal was to create a useful product for all viewers while providing thorough audio for students with blindness or low vision. The video not only aims to teach period folding but also seeks to provide an example of accessible content that is not dependent on visual acuity. This video allows low-vision students to explore the concept of period folding on par with their fully sighted peers.
GLAS Education seeks to provide comprehensively designed educational materials for equitable access to STEM content regardless of ability or disability. For more information about GLAS visit our website at glaseducation.org.
References
- Period-folding video
- Astronify download and documentation
- Reichart, D. E., "Robotic Telescope Labs for Survey-Level Undergraduates," The Physics Teacher, 59, no. 9, (2021): 728–729, https://doi.org/10.1119/10.0007416.