Long Wavelength Astronomy

Over most of the electromagnetic spectrum the earth's atmosphere absorbs radiation emanating from extraterrestrial sources.  However, there is an atmospheric window for wavelengths from 10 meters through 1 millimeter. Most radio telescopes operate at the shorter wavelengths of less than 0.3 meters.

A relatively new field of astronomical observations is emerging for long wavelength radio emissions with wavelengths greater than 1.0 meter.  At these long wavelengths, relatively low cost receiving stations can be built and dispersed to many locations around the world.

With the use of inexpensive omni-directional antennas and receiving stations, a phased array aperture synthesis telescope can be created. The direction of observation ("beam") is chosen electronically by phase delays between the antennas.

Multiple receiving stations outputs can be cross-correlated to greatly improve the signal to noise ratio of the receiving system. With very long base lines between stations, observations can be made emulating a telescope with a size of the baseline, and with many stations combining their outputs, an extremely sensitive astronomical observatory can be constructed.

Observation Targets

Many astronomical objects emit radiation at long wavelengths, allowing the following observations to be made:

Current Long Wavelength Observatories

Over the last decade several long wavelength projects have been funded and are underway.