What would the world around you look like if you were staring at a black hole?

This application places a black hole in the field of view of your iPhone’s camera and gravitationally "lenses" the resulting live video feeds just as a black hole would warp the light from surrounding stars. The resulting "Black Hole Vision" reveals interesting features of black hole lensing, including a "photon ring" of strongly lensed images around the black hole. The measurement of this photon ring will be the target of future astronomical observations from space with the Black Hole Explorer: an orbit satellite that will take the sharpest images in the history of astronomy! To learn more about BHEX, head over to https://www.blackholeexplorer.org/.

The code is open source and freely available on GitHub at https://github.com/graveltr/BlackHoleVision, along with documentation that explains the underlying black hole lensing equations and how they are implemented in Black Hole Vision.

The code was written at Vanderbilt University by Trevor Gravely with input from Dr. Roman Berens and Prof. Alex Lupsasca. We also acknowledge Dominic Chang for useful input and comments. This project was supported by CAREER award PHY-2340457 and grant AST-2307888 from the National Science Foundation.

The lensed image of the spiral galaxy Messier 101 was generated using material produced by NASA and STScI and can be found here: https://hubblesite.org/contents/media/images/2006/10/1865-Image.html?news=true.

License: This app includes a port of the GNU Scientific Library's (GSL) implementation of Jacobi elliptic functions and the elliptic integrals to Metal. It is licensed under the GNU General Public License v3.0 (GPL-3.0). You can view the full license and obtain a copy of the source code at: https://github.com/graveltr/BlackHoleVision.