The largest and most visible scientific instruments on the PARI campus are the two 26 meter (85ft) radio telescopes.  Originally constructed by NASA for communications with satellites and spacecraft, more than $3 million has been invested to enhance the telescopes and adapt them for radio astronomy. Sensitive multiple frequency receivers are being developed for research of a phenomenon called IntraDay Variables (IDV). IDVs are unseen clouds of matter in the Milky Way Galaxy. PARI’s radio telescope array will watch for changes in brightness from distant normally constant radio sources as they become obscured by these clouds of material.

Perhaps the best known PARI radio telescope is the 4.6 meter (15ft) antenna, nicknamed “Smiley” because a Smiley face was painted on the dish as a friendly wave to Soviet satellites during the Cold War era.  Smiley is used remotely over the Internet by middle and high school students and teachers to study radio astronomy.  Young learners investigate the rotation of the Milky Way Galaxy.  PARI conducts workshops to certify teachers and has developed several lab exercises teachers use in their classrooms.  The program has been supported by the NASA Space Telescope Science Institute IDEAS Program, the Z. Smith Reynolds Foundation, Progress Energy, American Institute of Physics Meggers Award Program and the American Astronomical Society.  To date, about 500 teachers and students have been certified and Smiley has been used by more than 3,000 students, some as far away as Australia.

PARI has a 12 meter (40ft) radio telescope housed in a radome. When funding is secured, it will be used for a survey of the Milky Way Galaxy at 22GHz for water masers – regions of star formation.  A similar survey has been completed in the Southern hemisphere but none have been conducted for the Northern hemisphere.  The survey itself will take about seven years to complete and requires a dedicated precision surface telescope like the PARI 12m.

PARI operates a low frequency antenna for studying the effects of Solar flares on the Earth’s ionosphere and the effects of the interaction of Jupiter and one of its moons, Io.  The project is part of a worldwide effort called Radio Jove, managed by astronomers at NASA Goddard Space Flight Center.