Amateur Pulsar Observations - PARI Facility

NOTE: All images presented here and a large part of the text has been downloaded with permission from this website.

Moe Wheatley (AE4JY) and Pieter Ibelings (N4IP) have detected 4 pulsars - B0329+54, B0531+21, B0950+08 and B1133+16 using the 26 metre PARI dish @ 327 MHz.  They were ably assisted by:

  • Charles Osborne, K4CSO provided overall RF support and antenna work.
  • David Moffett, provided current topocentric, Doppler-corrected pulsar rotation frequencies using TEMPO program.
  • Joe Taylor, K1JT, helped steer us towards an easier to see pulsar than our original target(Crab) and later provided some de-dispersion code examples for post processing.
  • The PARI staff for helping fix and debug the normal equipment problems encountered when operating equipment of this scale.

Background (extracted from the website)

Pulsars have always been a fascinating topic but seemed to be limited to the realm of professional radio astronomers due to the large antennas required and specialized receivers and computing resources.  While working on the RFSpace SDR-14 digital spectrum analyzer/receiver hardware ( ), it occurred to us that it may be possible to capture pulsars using this hardware platform.

The idea was to modify the SDR-14 hardware to allow an external trigger signal to be used to begin each block capture at precisely the same rate as the Pulsar frequency.  This would allow us to then process each block "in phase" with the pulsar period and average and integrate with the pulse position remaining stationary in time.

Modifying an SDR-14 to add an external sync signal was relatively easy and modifying SpectraVue to display Power versus Time was done in a few days as well as building and testing the Pulsar sync generator.  A GPS locked 10 MHz reference was input into a PTS-160 frequency generator that had a native resolution of 0.1 Hz.  By running the generator at a higher frequency and adding an external divider, a resolution of < 1 uHz was obtained.

The Antenna

The PARI facility antenna used to observe the pulsars.

The parabolic dish antenna is 26 meters in diameter and was operated at a wavelength of roughly 92 cm (327 MHz).

Operating Position

The operating position at PARI.

System Block Diagram

Showing overall configuration of the pulsar detection system.

The components inside the dotted line are the existing PARI hardware - the components outside the dotted line are those of the Wheatley/Ibelings system.

The Results (July 8-10, 2005)

The results of detection of 4 pulsars at 327 MHz are given by Moe and Pieter.  They are B0329+54 (~ 3300 ly), B0531+21 (the Crab Nebula pulsar - ~ 6,500 ly), B0950+08 (~ 1,000 ly) and B1133+16 (~ 1000 ly).






As freely admitted by Moe and Pieter - "Although the pulsars were observed by amateurs using simple hardware, the antenna system was hardly amateur " - the antenna aperture available to amateurs is the key limiting factor.