Amateur Pulsar Observations - Hannes Fasching  (OE5JFL)

NOTE: All images presented here and most of the text has been downloaded from this website with permission of Hannes. The information here is but a small sample of the detail available on Hannes's comprehensive website which details the latest pulsar 'trophy' count.

Efforts with a 7.3 m diameter offset dish by Hannes have seen the successful detection of 22 pulsars so far - as of 4th April, 2017 - on 424 MHz or 1294 MHz (or both).  He would like to acknowledge the assistance of others towards achieving his success, particularly Andrea Dell'Immagine (IW5BHY), as well as Mario Natali (I0NAA).

The two weakest pulsars detected as April 2017 are...

424 MHz: B1919+21 on 424MHz (S400 = 57 mJy)

1294 MHz: B0823+26 on 1294MHz (S1400 = 10 mJy)

...an impressive result !

Detected Pulsar List - 7.3 m Dish

The following pulsars were received as of April 4th 2017. Signal/Noise ratio measured with IW5BHY software.

Note *: The Crab pulsar was a challenge, 30 rotations/sec and high dispersion. Received at the first attempt!

Note **: The B2016+28 and the B2020+28 are only about 1 degree apart from each other. The 424 MHz profiles for both pulsars were obtained by analyzing the same recorded file.

System

Antenna:  7.3 m homemade offset dish, OE5JFL tracking system
Feeds: 70 cm (424 MHz) dual-dipole with solid reflector, 23 cm (1294 MHz) RA3AQ horn
Preamplifiers: 23 cm cavity MGF4919, 70cm 2SK571 (30 years old!)
Line Amplifier: PGA103+
Interdigital filter: designed with VK3UM software, 70 cm 4-pole, 23 cm 3-pole
Receiver: RTL-SDR (error <1ppm), 2 MHz bandwidth
Software: IW5BHY (Andrea), Presto, Tempo, Murmur (Mario - I0NAA)

Antenna

The antenna used by OE5JFL to observe pulsars.

The parabolic dish antenna is a 7.3m homemade offset dish, f/D=0.46 .

Results

The results of detection of two pulsars (out of 22) are given as examples below.  They are B0329+54 (approximately 3300 light-years away in the constellation of Camelopardalis) and B0950+08 (approximately 1,000 light-years away in the constellation of Antlia).

 The details of the two pulsars' ephemerides can be found on the ATNF database.

PSR B0329+54

------------------------------------------------------------------
#     NAME          RAJ         DECJ                P0      S400
                    (hms)       (dms)              (s)     (mJy)
------------------------------------------------------------------
1     B0329+54      03:32:59.3  +54:34:43.5   0.714520   1500.00
------------------------------------------------------------------

This pulsar is the second strongest of all pulsars at 400 MHz (1.5 Jy) after the Vela pulsar (5 Jy).

Hannes's results for B0329+54 using Andrea's software and Presto. In this 1294 MHz reception the pre-pulse and post-pulse of the B0329+54 normal mode can be seen very well.

b0329_pre_pot_pulse

The corresponding result from Presto...

PSR B0950+08

This pulsar is a more difficult target as it is about 6 dB weaker than B0329+54 at 400 MHz.

------------------------------------------------------------------
#     NAME          RAJ         DECJ                P0      S400
                    (hms)       (dms)              (s)     (mJy)
------------------------------------------------------------------
1     B0950+08      09:53:09.3  +07:55:35.7   0.253065    400.00
------------------------------------------------------------------

Hannes's 1294 MHz result for B0950+08 using Andrea's software and Presto.

The corresponding result from Presto...

Verification Tests

Verification testing is an important part of validating results.  Hannes has provided some good examples of such verification.

Pulse Period Check: Verification was done by plotting the S/N in the folded profile against fold period.  This showed a distinct peak at the pulse period of the B0329+54 pulsar at 424 MHz.

Dispersion Measure Check: More verification is done by plotting the S/N of the folded profile against de-dispersion delay (ms/MHz).

Hannes has used IW5BHY's program to do the two verification checks mentioned above to confirm if the pulses are likely to come really from a pulsar and not RFI. The folding time (useful on 70cm and 23cm) and the dispersion time (useful only on 70cm) are varied and the change in S/N plotted. As an example Hannes performed these two tests for the 424 MHz recording of B0329+54. The left picture shows S/N depending on varying the folding frequency, in the right picture the dispersion time is varied.

Hannes's results are certainly impressive.  Further details of the 7.3 m dish results can be found here.