MIT Near Real Time Correlator

The latest HALCA satellite auto-correlation spectra are shown when the Green Bank Earth Station is tracking HALCA. Also the NRAO 140 ft telescope auto-correlation spectra may be displayed. Both HALCA bands (A and B) are displayed below. The spectra have 512 channels in the 16 MHz total band width. The spectra are based on 1 second of data taken automatically by the MIT Near Real Time Correlator every few minutes. The raw data are fourier transformed and the spectra are averaged. Each plot shows the HALCA spectra at least once. The second of two graphs on each plot is either the NRAO 140 spectra or additional HALCA data. If the two lines are similar, the data are probably both from HALCA (ie. the 140 is not set up to observe).

The dates of the data extraction are encoded in the top plot label. The label contains a string indicating which file is used to produce a plot. These files are given names based on the time of data capture at the MIT-NRC. The name format is MMDDHHMM.A for HALCA IF A and MMDDHHMM.B for HALCA IF band B. (MM is the two digit Month code, DD is two digit day of month code, HH is two digit hour of day code and MM is two digit minute of hour. Halca A channel Data captured on August 15 at 12 hours 24 minutes has name 08151224.A)

Note! Because this is a Real-Time Spectrometer, if Green Bank is not Tracking HALCA, there are no valid space data and the space Spectrum is Flat!

Current Spectra


Spectra images are updated every few minutes. The images above are linked to encapsolated postscript files, providing higher resolution images of the data.

If the tracking station is not tracking HALCA, then the MIT-NRC captures pseudo random noise generated by the station decoder. The spectrum of this data is flat.

Other Web Sites

Return to the NRAO Green Bank Tracking Station page.

The MIT Group maintains a description of the latest MIT NRC results.

VSOP/HALCA has a home page. The VLBA Correlator NRAO Socorro is developing other hardware and software for the NASA OVLBI project. There is a Space VLBA Correlator home page as well.

Return to the Station Software Guide. The National Radio Astronomy Observatory (NRAO) is a facillity of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.
Last update: 97 August 15