Parkes Observatory report

Staff

Michael Grimshaw has joined the band of casual staff looking after the ever increasing number of people passing through the Visitors Centre. We have been waiting for the "post-Dish" peak for some time, but Visitor Centre numbers and activity continue to grow steadily.

Martin McColl is leaving us in November to take up a position with the Sub Millimetre Telescope group in Tucson, working with Harry Fagg.

Coffee, foccaccia and other goodies

Progress towards the establishment of a cafe in the grounds of the Parkes Visitors Centre continues, and is now clear for all to see after the relocation of the six-sided BBQ shelter from the VC grounds to the Quarters. A contract has been signed with the tenants, Michael and Andrea Carter, who will operate the cafe and are raring to go. The tender for the construction of the cafe and the new BBQ area is to be finalised this week (starting 7 October). Construction is to be completed in 16 weeks, which should see the cafe open at the end of January 2003.

CPSR2

A frenetic fortnight in August saw the installation of a new supercomputer facility in the upstairs control room. Currently called CPSR2 ("Caltech Parkes Swinburne Recorder 2") the equipment makes an impressive sight, comprising 30 Dell 2650 rack-mounting PC servers, each containing two 2-GHz CPUs, interconnected on a GigaNet network (for the data) and a 100 Mb/s ethernet network (for control).

Two of the main design goals of the new system were to (a) significantly increase the recorded bandwidth over the earlier system, and (b) record direct to computer disk and analyse the data on-site in near real time, avoiding the use of tapes. The new system can record 1 Gbit/second, comprising four
64-MHz bands sampled at two-bit precision. This is an order of magnitude more than the first CPSR baseband recorder (or the S2 VLBI recorder), giving access to many more pulsars than any previous baseband system.

The system records direct to IDE disk, and can record at full speed for several hours before the disks fill. Reducing the data on the present system takes about twice real time, but can run in parallel with data-taking, thereby extending the maximum continous observing period.

The system at present is sitting in temporary open racks, but will soon be installed in two fully shielded cabinets to reduce RFI (and fan noise!).

The system is intended primarily for pulsar timing but has stimulated discussion of potential applications in other areas, particularly VLBI.

Mars tracking

A contract between the ATNF and NASA/JPL for the use of the Parkes Telescope for tracking spacecraft over the period September 2003 _ March 2004 has recently been signed. The contract will see NASA pay around A$3 million to upgrade the surface of the telescope, commission ATNF to build a new 8.4-GHz receiver, and to operate the telescope for tracking spacecraft for around 1000 hours. The surface upgrade will enlarge the area of perforated Aluminium panelling from 44 m to 54 m diameter, replacing about half of the remaining original steel mesh panels. The new surface will significantly improve performance at all frequencies above about 8 GHz. Combined with the new receiver and feed, the sensitivity of the telescope at 8 - 9 GHz will be approximately twice that of the existing system.

The choice of receivers available for astronomy observations during the five to six month main tracking period will be somewhat constrained. In particular, a choice will need to be made between the HI Multibeam receiver and the new 10/50 cm pulsar receiver. One of these will be unavailable for the duration of the tracking.

The return of Parkes to space tracking is being driven by the large number of spacecraft converging on Mars, or in the same sidereal range, towards the end of 2003, heavily taxing existing NASA tracking resources. The decision on which of these spacecraft will be tracked by Parkes is yet to be made, and may occur dynamically at the time of the tracking. For more information, see www.csiro.au/index.asp?type=mediaRelease&id=MarsTrafficJam

Operations news

Generally operations have continued smoothly into 2002, with lost time for the year to date running at about 1.0% for equipment faults and about 3% for bad weather / high winds.

Problems were experienced in June and July with a failed DLT tape drive on the Multibeam Pulsar filterbank system, which seemed to precipitate a number of minor but irritating problems particularly at the faster sampling rates. Much work has since been expended in upgrading the main data-taking computer (to a DEC Alpha XP1000) to improve system performance and reliability, with promising results in preliminary testing.

Commissioning of the Wideband (1 GHz) Correlator during March and April was not as successful as hoped and has been rescheduled for October, during the elevation gearbox replacement shutdown.

The Multibeam receiver continues with one dead channel (10A) and a few others with slightly degraded and/or erratic performance. Approximately 15 new LNAs are in the process of being built at Marsfield with a view to overhauling the Multibeam package sometime in 2003.

Operational developments

New zenith drive gears have just been fitted to the telescope and as we enter the fourth week of the maintenance shutdown for this work, everything is proceeding very smoothly. The gearboxes were removed (for only the second time in 40 years of operation) on 20 September. After a complete new set of gears and bearings were fitted in both boxes, they were reinstalled on 4 October.

For a pictorial representation of the job so far, look at the pointers under `Happenings at Parkes' on www.parkes.atnf.csiro.au/visitor_info/visitor_info.html

At this stage particular thanks are due to staff from other sites who have made a great contribution to the work involved in this major job, namely Brian Wilcockson, Steve Broadhurst, Clive Murphy and Ollie Dowd. Steve's wife had a baby, Penelope Avril, on the last morning Steve was to be in Parkes. As a result Steve missed seeing the gearboxes go back on the telescope, but we believe he made it back to Sydney in time for a very different but equally miraculous event!

As this report is being written, two gear experts from Hofman's, a Perth based gear company, have begun grinding each tooth on the racks that the output pinions from the gearbox mesh with to lift the counterweight and tip the dish. The grinding is expected to take all week. We will then have a few days of system tests and be back in normal operation from 18 October.

John Reynolds
Parkes Officer-in-Charge
(John.Reynolds@csiro.au)