The app, SpyMeSat, provides notifications when spy satellites and unclassified imaging satellites are zooming above your head and may be taking your picture.
All of the imaging satellites in SpyMeSat are in low-Earth orbit at an altitude of about 805 kilometers.
Enabled SpyMeSat satellites include such zoom-lens notables as GeoEye, the French space agency's SPOT-5, India's CartoSat-2A, DigitalGlobe's WorldView satellites and Canada's RADARSAT-2.
"I actually got the idea for the app from talking to friends outside the aerospace industry who were always very interested in space and satellites and imaging from space. This app answers those questions in a fun and interactive way," said Alex Herz, president of Orbit Logic in Greenbelt, Maryland which developed the app.
The app uses available public information about commercial and international imaging satellites. It also uses orbit data from the North American Aerospace Defense Command (NORAD).
SpyMeSat does not include all imaging spacecraft. No classified imaging satellites, from any nation, have their orbit information published, so these satellites do not show up in the app.