Parkes Observatory report

Staff

After advertisement of the Parkes Deputy Officer-in-Charge position, Lewis Ball has accepted an indefinite appointment. In addition to duties at Parkes, Lewis will have a major role in strategic Human Resources for the ATNF as a whole.

Karin Unger has joined the casual staff who keep the Visitors Centre ticking over.

Urumqi receiver shipped

Mr Sun Zheng-Wen and Mr Wang Wei Xia, engineers from the Urumqi Astronomical Observatory in China, have returned home with a new cryogenic L-band (18-cm) receiver built at the ATNF. Sun and Wang have spent almost a year living and working at Parkes building the receiver, with the tireless assistance of Martin McColl. Jon Crocker has also played a major role in the process, completing the metal fabrication and machining at the very high standard required. Many other also contributed to this very successful project, particularly Graeme "Herbie" Gay of Marsfield who made key contributions in the design of the receiver and with logistics.

The new receiver is the first cryogenic receiver to be installed on the 25-metre Urumqi telecope, and replaces the existing room-temperature L-band receiver.

Martin will travel to Urumqi later this month to assist in the installation of the new receiver, which arrived safely (we hope!) in China in mid-June. Dick Manchester, whose close scientific ties with Chinese astronomers were instrumental in setting up the contract, will also travel to Urumqi to help set up the observing system which will be used primarily for studying pulsars.

Sun and Wong became part of the Observatory "family" over their extended visit and leave behind many friends and happy memories. We eagerly await news of their repatriation when Martin returns!

Eclipsing millisecond pulsar discovered

The combination of observations with the Parkes Telescope and with the Hubble Space Telescope has revealed a millisecond pulsar J1740-5340 which is periodically obscured by a red companion star.

Nichi D'Amico and Andrea Possenti from the Astronomical Observatory of Bologna targeted 96 `globular clusters' - tightly packed balls of stars on the edge of our Galaxy that are known breeding grounds for millisecond pulsars. J1740-5340 was found in a globular cluster called NGC 6397. The pulsar is hidden by its companion star for about half of each 1.35 day orbit.

Francesco Ferraro and collaborators from the Astronomical Observatory of Bologna hunted through archival data from the Hubble Space Telescope and the European Southern Observatory and identified an unusually red star at the pulsar position. The shape and brightness of the star fluctuate in step with the pulsar's orbit because of the distortion of the star by the gravitational effects of the pulsar.

The pulsar is apparently dragging material from its red companion, and this discovery of the first such system may shed new light on models for the evolution of millisecond pulsars.

For more information , look at the News from Parkes links on http://www.parkes.atnf.csiro.au/visitor_info/visitor_info.html .

Parkes Multibeam Pulsar Survey completed!

The long-running Parkes Multibeam Pulsar Survey, a major survey of the Galactic plane using the 20-cm Multibeam receiver and dedicated pulsar filterbanks, was completed on 14 March 2002. Michael Kramer (Jodrell Bank), Paulo Freire (Arecibo) and Dion Lewis (U.Tas./ATNF) were the observers for the final pointing, representing a team of a dozen or so pulsar observers for whom the Parkes quarters have become a second home.

Observing for this survey, a collaboration between Jodrell Bank, ATNF and the University of Bologna, commenced in 1997 and has been one of the Observatory's principal research activities in the intervening 5 years.

The success of the survey has exceeded all expectations, with more than 600 new pulsars already found and another 100 or so expected to be revealed when the data are reprocessed. The survey will then have roughly doubled the number of pulsars known, with around two thirds of all known pulsars having been discovered with the Parkes telescope.

The Parkes Multbeam Pulsar Survey has its own Web page at http://www.atnf.csiro.au/research/pulsar/pmsurv/ .

Pulsar workshop

Lewis Ball and Simon Johnston hosted a two-day Pulsar Science workshop at Turner's Vineyard, Orange, in March. Many of the most exciting recent developments in observational and theoretical pulsar research were presented. The meeting was funded by a grant under the International Researcher Exchange (IREX) scheme to fund collaborative pulsar research between Australia and Germany, and was attended by around 30 pulsar astronomers, including all but one of those on the grant. A number of attendees took the opportunity to visit the Observatory after the meeting.

Operations news

Operations continue to run smoothly with no major problems. Lost observing time remains dominated by high winds, accounting for 4.5% of total time for the year to date. Time lost to equipment faults is currently 1.2% over this period.

We experienced a minor Easter Miracle when beam 8B of the 21cm Multibeam receiver was found to have returned to life. The first stage LNA of beam 8B had died during routine cryogenic maintenance in November 2001. After similar maintenance in June 2002 beam 8B is still alive and well, but failures of the LNAs in two other channels in the outer beams have now occurred (10A is currently unusable and 12B is about 10K higher than normal). This establishes a trend of failures resulting from the thermal cycling associated with essential six-monthly maintenance, and options for future removal and refurbishment of the receiver are now being actively considered.

The pulsar filterbank is exhibiting unexpected noise levels around 1 - 3 Hz in 512 channel mode. This has had a negative impact on deep searches for slow pulsars. The cause appears to be related to power supply problems - investigations are continuing.

Operational developments

A contract for the use of the Parkes telescope by NASA for tracking spacecraft associated with a traffic jam on Mars in late 2003 and early 2004 is expected to be signed in the next few weeks. The contract will involve an upgrade of the telescope surface, with around 1000 square metres of the galvanised wire mesh to be replaced by perforated aluminium panels. The panels will be fitted around May 2003, taking the diameter of the perforated surface from 44 metres to 54 metres. A considerably upgraded X-band (8 GHz) receiver will also be built as part of the contract. While the details of the schedule are yet to be decided, it is likely that the telescope will be involved in tracking for around 10 hours per day between September 2003 and March 2004

New zenith drive gears and pinions have been manufactured in Brisbane and Perth and are about to be shipped to the Observatory. A major shutdown of around six weeks is planned in September 2002 to allow the installation of the new gears and the refurbishment of the teeth on the zenith racks.

The new pulsar Wide Band Correlator was installed in the tower on 25 March. Commissioning work revealed some hardware and firmware problems that have so far resisted the herculean efforts of Warwick Wilson, Evan Davis and other members of the electronics group. The next attempt to install the WBC is expected to occur at the end of the September shutdown.

The new 10/50 cm pulsar receiver is taking on impressive proportions. A test of the logistics of the installation of this substantial package will take place towards the end of 2002, with the receiver expected to be usable around the end of the January 2003 observing term.

Outreach

The number of public visitors to the Visitor Centre continues to climb, delighting (and exhausting) the staff whose role is at the pointy end of satisfying public interest. Numbers for the first three months of 2002 indicate a further increase of around 30% over the same period in 2001, pointing towards an astonishing total over 150,000 visitors for 2002 if the trend continues. New point of sale software has been installed to help cope with the sales of products and tickets to the AV shows and is working very smoothly.

Media interets in the Dish also continues unabated. The Parkes role in the Apollo 11 mission featured in a recent episode of ABC TV's Dimensions in Time program, and the imminent release of the movie The Dish in Japan is prompting a number of requests from film crews for visits to the telescope and interviews with both current staff and old timers.

John Reynolds
Officer-in-Charge
and Lewis Ball
Deputy Officer-in-Charge
(John.Reynolds@csiro.au)