Discovering the Invisible Universe GAVRT Chapter 1

Karl Jansky (1933) Trying to build antenna that would not be susceptible to static from T storms Hiss peaked 4 minutes earlier each day Pattern corresponded to sidereal day

Grote Reber (1937) Built first modern radio telescope Made first radio map of sky (1944) Identified source of Jansky’s hiss as Milky way Picture of Reber’s Telescope

Characteristics of Radio Signals Proportion of radio waves that reaches earth compared to visible light is small Radio waves cannot be seen or heard by humans Radio waves passing through an electrical conductor (wire) will induce a current.

Radio Telescopes Need large aperture (diameter) to collect signal over large area. Parabolic shape focuses radio waves to one point where they induce current in conductor Arrayed telescopes effectively increase telescope diameter Interferometry allows telescopes to see more detail Very Large Array in New Mexico is example of arrayed telescopes

The GAVRT Telescope 34 m in diameter, Cassegrain design, Hour angle, declination mount S and X band receivers Built as part of Deep Space Network in 1960 Used by NASA for Echo. Voyager, Magellan, Donated to AVSTC in 1996 Present GAVRT Missions include: Jupiter Quest, Uranus Storm Study, Variable Quasar Project Add picture of GAVRT telescope at night

New GAVRT http://www.gavrt.org/