Black Hole Vision vs Below Me

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.

What's on the other side of the horizon? Point your iPhone or iPad at the horizon, tilt it down, and Below Me shows you the countries that lie beyond the curve of the Earth, as if you could look straight through the planet. Below Me isn't a map. It's a window. Every border you see is placed where it really is from where you stand: computed on the WGS84 ellipsoid with great-circle math and projected through the Earth along your line of sight. Tilt further and the countries get farther away. Point straight down and you're looking at your antipode. FEATURES • Live AR view: country borders, sea names, a labelled 10° grid and distance labels floating over your camera image • Crosshair readout: which country or sea you're looking at, how far away it is and in which direction • Info panel you can fold away to a small tag for a clear view • Mini globe showing your position and line of sight, drag it to spin • Outdoor mode that dims the camera for bright daylight • Colour tints for land and seas, thin or bold borders • Choose kilometers or miles • English and German • Works offline. No account, no tracking, no internet needed FREE Explore everything within 5,000 km of where you stand. PRO – ONE-TIME PURCHASE • Whole Earth: range up to 20,000 km, all the way to your antipode • Place search: any country, 34,000 cities offline or any place worldwide via Apple Maps. Up to five red markers, and an arrow guides you there through the Earth • Relief: mountains, shelves and deep-sea trenches as coloured, shaded terrain • Your exact antipode, marked in yellow straight below your feet • Fine borders and coastlines (Natural Earth 1:10M, five times more detail) • Home marker: a red dot shows where home is when you travel • Major cities with distance • Local time at the point you're looking at • Country info card: outline, capital, area, population, currency, calling code, languages • Live day-night line and the sun through the Earth: tilt down at night and see where it's shining right now • Simulate a location: explore the Earth from New York, Tokyo or anywhere else Buy once, keep forever. Family Sharing included. No subscription. For the curious, travellers, teachers, pilots, sailors and anyone who has ever stood on a beach and wondered what lies out there. Requires an iPhone or iPad (iOS 18 or later).