Ripple is a mobile application that collects real-time, crowdsourced data about astronomical events. When a user takes a photo of an event, anybody within a 1-mile radius gets an alert asking them to take a photograph too, if they can see it. Events are quickly "rippled" out as each photograph is taken so that accurate data can be gathered about where events were visible from. Ripple also collects high-quality photographs for later analysis.

This project is solving the Alert-Alert! challenge.


When you take a photo of an astronomical event with Ripple, everybody around you is invited to also take a photo. A thumbnail of the original image is displayed so that the user knows what they are looking for. If they can also see the event, they take their own photo and everybody around them is alerted, and so on. If they are unable to see an event from their current location, a simple shake of their device dismisses the camera and marks their location beyond the viewing area of their event.

Ripple also allows users to browse events, seeing each photo, where they were taken, and the area in which the event was visible. Ripple has the potential to collect a vast amount of useful data about rare astronomical event.

Project Information

License: MIT license (MIT)

Source Code/Project URL:


Screenshots -


  • Ross Penman