True, most telescopes have narrow fields of view and are hence unlikely to endure many wiped-out exposures. But the Iridium spacecraft will follow one another only 9 minutes apart on near-polar orbits, five or six of which lie above the horizon at any given time. Furthermore, they will be visible to many of the world's astronomers for much of the night during summer months.
Radio astronomers have a lot more to worry about.
Thus the Iridium armada could affect their observations of such things as cool stellar atmospheres and extragalactic masers. The satellites will start exchanging radio waves with portable telephones and pagers on November 1, 1998. Consequently some radio astronomers have argued that Iridium should be denied operating licenses. Astronomers continue to wonder whether and how Iridium will keep up its end of the bargain. In early 1998 the telecommunications firms worked with NRAO astronomers to measure the OH-band emissions from several Iridium satellites.