The Parallax Telescopes were a system of eight telescopes positioned at the edges of the solar system to provide various information and imaging. 
The Parallax Telescopes were created for Project Parallax by Juke Limited in order to collect information from deep space. The eight telescopes were placed at the edges of the solar system and would focus on various galaxies. The Parallax Telescopes sent information to the Parallax Nexus on Earth, so various universities and STASA could subscribe to the system in order to have access to deep space information. 
Juke Limited used the telescopes to receive information on their rivals' movements within the solar system in order to beat the competition.
During the First Formic War, the telescopes did not notice the incoming Formic scout ship because they were not trained to notice the flight patterns of the ship. The Parallax Telescopes were unable to send information to Earth as the scout ship traveled toward Earth because it released gamma radiation. Once the gamma radiation cleared up, Ukko Jukes revealed the telescopes to his son and showed him that the remaining El Cavador crew were still alive.
The Parallax Telescopes were used after the First Formic War to track the incoming Formic mothership and fleet. As the mothership neared Earth, a Formic fighter sent ahead of the fleet destroyed the most important telescope, Copernicus. Using International Fleet fighters, the Hegemon Ukko Jukes quickly retaliated, destroying the Formic ship. He later reported of the destruction of Copernicus to Earth, which incited fear and panic.
Some time later, however, the remaining seven Parallax Telescopes were also destroyed simultaneously by Formics.