A Data Science Project for Eclipse Watchers
Quick Success Data Science
I live only a couple hours' drive from the path of totality for this year's eclipse, and it drives me crazy when people say that they're staying home because "95% of the sun will be covered and that's good enough."
I can assure you it is not good enough. Not by a long shot. I saw totality in 2017 and, while I won't call it "life changing," it was definitely one of the great events of my life.
Here's the thing: the sun is 480,000 times brighter than the full moon. When 95% of the sun is occluded – even accounting for limb darkening – it's still over 7,000 times brighter than the moon! That's the same brightness as an overcast day.
And because it takes about 75 minutes for totality to arrive, your pupils easily dilate to keep up with the waning light. For most of the eclipse, you can't even tell it's happening.
Totality, when the sun is completely covered, is over 200x darker than an overcast day. The temperature plummets. People gasp in awe. Birds stop singing. Your neck hairs stand on end. A black sun surrounded by silver radiance dominates the sky and your brain struggles to make sense of it.
In this Quick Success Data Science project, you'll gather data to document the evolving Light Curve during a solar eclipse. This will make a nice STEM project for older children and will capture the dramatic change in illumination during the last few minutes before totality.
Data scientists use data every day but don't often get a chance to "give back" by acquiring new data. To that end, this article includes links to other eclipse projects that allow you to contribute to larger data-gathering efforts in the role of "citizen scientist."
The Light Curve Project
The goal of this project is to plot the change in illumination as the eclipse progresses. Almost everyone in the USA will see at least a partial solar eclipse and can participate. To reproduce the full light curve, however, you'll need to be in the path of totality (see this map for locations).
What You'll Need
You'll need the following equipment:
- A digital light meter
- Paper and pencil (not necessary if light meter can record the time and measurement)
- A clock (not necessary if light meter can record the time and measurement)
Ideally, you'll want to have clear skies.
Recording Illuminance Values
To capture illuminance values, you'll need a light meter. You can find inexpensive versions on sites like Amazon by searching for "digital light meter."
Alternatively, you can download a light meter app on your phone. This may become inconvenient, however, if you want to use your phone for multiple tasks, such as for taking pictures and recording sample times.
The light meter manual should include instructions on which direction to point the light sensor relative to the light source. In many cases, this is perpendicular to the source.
You can find the starting time for the eclipse for your location at Total Solar Eclipse on April 8, 2024: Path Map and Times (timeanddate.com). You'll want to take at least one reading before the eclipse starts, to use as a baseline.
You'll then want take readings every 3–5 minutes until about 10 minutes before totality, at which time you'll want to decrease the sample spacing to around a minute. (Since software can interpolate between points, there's no need to overdo it). I would take only one reading during totality so you can focus on enjoying the spectacle.
Plotting the Data
The ultimate output will be a chart like the one below. You can plot this on graph paper in real time or record the values and produce the chart later. Using software like Excel or Python will allow you to "fit a curve" to the data points.
The light meter units will be in lux, which are lumens per square meter. As per Wikipedia, a lumen is the unit of luminous flux, a measure of the perceived power of visible light emitted by a source, in the International System of Units (SI).
Luminous flux represents the amount of visible light emitted by a light source or received by a surface. It differs from power (radiant flux) in that radiant flux includes all electromagnetic waves emitted, while luminous flux is weighted according to a model of the human eye's sensitivity to various wavelengths.
The following chart documents the lux readings for multiple conditions. Totality falls between twilight and deep twilight, such as experienced after the sun sets. You can use this table to help annotate your chart.
For most of the eclipse, the dimming (or brightening, if you're recording the post-totality event) is very gradual. Things start to change rapidly minutes before totality, as shown by the steep decline in the light curve. This rapid dimming will result in a surge of excitement, and you may very well forget to record values!
When you complete your chart, be sure to post it on social media to show your friends and relatives how clever you are.
Other STEM Projects for the Eclipse
If light curves aren't your thing, here are some other eclipse projects suitable for "citizen scientists."
SunSketcher Project
This project uses the free SunSketcher app and your phone's camera to record the event and help astronomers study the sun's oblateness. Oblateness refers to a sphere that is flattened at the poles and bulges at the equator due to centripetal force produced by rotation.
The goal of the SunSketcher project is to acquire millions of measurements from near the eclipse centerline on April 8. The ultimate goal is to improve our understanding of the sun's shape.
You can read more about SunSketcher at this site and download the free app here. You can find the centerline for the eclipse on this map.
Recording Environmental Effects
NASA is calling for volunteers along the path of totality to contribute to its ongoing Eclipse Soundscapes Project. Through the use of visual, audio, and written recordings, researchers will increase their understanding of the influence of the eclipse on regional ecosystems.
Science on the Edge
The International Occultation Timing Association (IOTA) has been monitoring variations in the sun's diameter for decades. This requires observations of the edge regions of both annular and total solar eclipses. You can contribute too, assuming you have a telescope, solar filter, a video camera, and a few other items. For the details, see Chapter 11 (page 238) in the IOTA manual.
You can find additional projects at science.nasa.gov and by doing an online search for "Citizen Scientist Projects For the 2024 Solar Eclipse."
Viewing Safety
As you may have gleaned from this article, even when 99% of the sun is covered, it is still too bright to safely view without eye protection. You'll need proper eclipse-viewing glasses rated ISO 12312–2. For more guidelines, see NASA's official site on Eclipse Safety.
Summary
The lifeblood of data science is data, and the 2024 solar eclipse gives data scientists the opportunity to "give back" to the community by acquiring and sharing useful astronomical data. The light curve project described here is a fun and easy way to introduce kids to science. Many more citizen scientist projects are available and allow you to contribute to ongoing astronomical research at NASA and elsewhere.
Thanks
Thanks for reading and please follow me for more Quick Success Data Science projects in the future.
