Astrophysics (Index)About

very-long-baseline interferometry

(interferometry based upon storing timing data at each telescope)

The term very-long-baseline interferometry (VLBI) is self-explanatory, but is taken to imply a radio telescope interferometry technique suited to baselines sufficiently long to make real-time processing of the signals unwieldy. The signal data as well as its timing are stored at each telescope and later processing of the collected data determines the exact direction from which the signal came, allowing telescopes far apart (e.g., thousands of miles) to be used. Its use has achieved angular resolutions in the 10 microarcsecond range. VLBI arrays often use existing distantly-separated telescopes, and may be short-term projects, such as for specific surveys. Some VLBI arrays:

A recent development is electronic very-long-baseline interferometry, which is near-real-time transmission of the data for immediate analysis.

While VLBI clearly is useful for observing sufficiently bright radio sources, it offers as a byproduct, measurement of changes in the distance between receivers, down to the millimeter range, and reveals the effects of plate tectonics.

Further reading:

Referenced by pages:
Australia Telescope Compact Array (ATCA)
Dominion Radio Astrophysical Observatory (DRAO)
Earth rotation synthesis
Earth-sized VLBI
electronic very-long-baseline interferometry (e-VLBI)
European VLBI Network (EVN)
Green Bank 140 Foot Telescope
Green Bank Observatory (GBO)
Greenland Telescope (GLT)
Gould's Belt Distances Survey (GOBELINS)
high-resolution imaging
International Celestial Reference System (ICRS)
Jodrell Bank Observatory (JBO)
Mark II (MKII)
Max Planck Institute for Radio Astronomy (MPIR)
Next Generation Very Large Array (ngVLA)
OH/IR source
radio astronomy
speckle masking
spectral correlator