Period folding is a process for tracking and graphing the light curve of a variable star. It can be a difficult concept to grasp for sighted students and researchers. For the blind and visually-impaired, it can be nearly impossible. GLAS interns Shiloh Miller, Maire Lucero and Sofiia Lauten spent this summer working on a way to make period folding more accessible to blind and visually impaired (BVI) students and researchers by sonifying the data.
Sonifying, or sonification, involves assigning musical notes or tones to data to make it recognizable by ear. The interns did a lot of research about period folding and a lot of brainstorming on how to translate it into nonvisual data. They then experimented with several sound and sonification programs to find the right combinations of notes to properly convey astronomical data. Their work included creating a sonified video explaining period folding to students who are BVI.
Kate Meredith, GLAS director, said the accessibility project came out of an undergraduate astronomy curriculum called OPIS!, Our Place in Space. Because period folding and sonification are complicated, it sat around uncompleted for at least two years. This year was going to be different. “We had at least three sessions where we sat down all together to work out to get as far as the story board before we started to divvy up tasks,” Kate said. In addition to working with Kate, the interns also turned to Jennifer Kotler of the Space Telescope Science Institute, who designs easily accessible data search and analysis tools for telescope missions.
Some background: Simply put, period folding is a process to discover and graph the pulsations of variable stars. Variable stars pulsate between the same levels of brightness, from relatively dim to relatively bright at a regular rhythm.
According to Shiloh, period folding is a real world solution to real world astronomical problems when observing and graphing data from a variable star. “The changing brightness of a variable object, a variable star, can be graphed as a light curve, and this is periodic function that repeats at the same interval,” Shiloh said. “But often this data is really spotty. The atmosphere can mess it up or you don’t have all the time in the world to make these measurements.”
Real world data collected from one observation of a variable star can look like a bunch of unrelated dots on a graph. Astronomers make multiple observations of the same variable star. Then, using some educated guess work, they are able to “fold” the observations into a single graph showing the variable star’s period.
“Period folding is a very complex concept. However, often times when people explain the concept of period folding, they really rely on the graphs,” said Maire. However, visual graphs are not accessible to blind persons. “So, thus, we wanted to make an accessible video explaining period folding to blind individuals using high contrast images and sound and audio to explain it,” Maire said.
“Through out this project we were able to understand what makes the material more low-vision accessible,” Sofiia added. That meant removing excessive information, incorporating more narration instead of text and visuals and including alternatives to visuals, like sound or tactiles. That also means, when using sound, choosing easy-to-follow instrumentation, tempo and range of pitches. “We found if we use a very distractive instrument, we tend to focus more on the music aspect of it and not the actual analysis,” Sofiia said. “So, it’s a bit hard fine tuning it between making it sound objective, still pleasant, but also practically reflective.”
After storyboarding the video, writing a script and gathering the necessary variable star data, the interns tested a variety of programs to find the right sounds for the sonification video. They started with a sonification program called Highcharts, but then went to Astronify. Astronify wasn’t perfect, either, Maire said. “With Astronify we came into a lot of bugs, like it wasn’t recording the full data which was very problematic,” she said. The interns didn’t get the bugs worked out until after the video was completed, which led to a rerecording of some of the data.
Sofiia placed all of the data files on Audacity, a recording software. What the interns discovered was that the sound file on Astronify was a bit to quick and flutey. “We wanted to make it easy to use but still nice to hear so it wasn’t an earsore,” said Maire. And also, the Astronify file I personnally noticed was rather out of tune and they (the notes) were kind of slurred together so you couldn’t distingquish each data point.”
The interns cleaned up the sounds and aesthetics on a music composing app called Garageband. Maire said the data from Astronify was slowed down and the data points were made short and punchy with the use of an electronic sound called “plastic piano.” Plastic piano resembles a piano, but doesn’t actually sound like one. Maire said that was intentional. Using a real instrument, like a piano, can be distracting to someone listening to the data, she said.
The next step was to record the audio. This was fun, but sometimes stressful, Maire said. They padded a closet in the GLAS office with blankets and pillows to create an improvised recording studio. The office airconditioning was turned off to reduce outside noise. When it became apparent that the microphone was finnicky and picked up noises from the computer. The computer was placed under a box to further reduce ambient sound.
“Once I had the big audio file of the script, I put it into Camtasia, which is video editing software,” said Shiloh. “I cut out all the parts where we restarted and then I added in the sonification files.” Shiloh worked on illustrations and animations for the video. The biggest challenges in creating the visuals were learning to use Adobe Illustrator and creating consistency for the animations, Shiloh said. There was a learning curve. “Camtasia was a pretty user-friendly easy to understand software. The same cannot be said for Adobe illustrator,” Shiloh said. There was a lot of trial and error with Illustrator, she said. “But I figured it out.”
She did occasionally turn to others for help. Kate helped with video editing. “I got a lot of help from Kate for Camtasia, because Kate has had experience with that before,” Shiloh said. Shiloh also turned to Jenn Kotler. Kotler has experience creating accessible videos and using Adobe Illustrator. “She kind of showed me the ropes in that regard,” Shiloh said.
Once the video was wrapped up with sound, illustrations and animations, the project still wasn’t done. The interns needed some third party reviews. “We showed the video to several people and got some feedback on things to change,” Shiloh said.
Among those reviewing the video was Olivia Smithmeier, an education consultant for GLAS who is also visually impaired. Then it was back to setting up the recording studio again for further editing.
Kate said she was gratified to see the project completed. “What I appreciated about this project is that we started talking about this project two years ago when the OPIS project started and we poked at it each summer and then gave up because it was complicated,” Kate said. “So this time, we were determined that it had to get done. And it literally was the four of us,” she said. Kate said she showed the finished project off to the OPIS professors the week before the interns’ presentation. The link to the GLAS period folding sonification video is https://tinyurl.com/2y728us