Parkes Observatory report

Chief Executive visit

The CSIRO Chief Executive Officer Geoff Garrett visited the site on 5 August, accompanied by his wife Janet, their first return visit since 2001. The visit included an informal "Q&A" session which was much appreciated by staff, and a comprehensive inspection of the site. Peter May, recently appointed as Executive Director, CSIRO People and Culture, was also present and this was his first visit to the site. The visit also gave Dr Garrett an opportunity to talk at length to two overseas-based astronomers currently visiting the Observatory.

The visit was "double-headed" with a visit by a group of CSIRO Alumni, accompanied by Susan Smith from the CSIRO communications group. The visiting alumni, about 15 in number, were formally welcomed by Dr Garrett before joining him, Janet, Peter, and local staff in the Dish Cafe for lunch. The alumni were then given a tour of the telescope, which was very well received. The feedback from all visitors on the day was enthusiastic, and the inaugural CSIRO Alumni event at the Observatory pronounced a great success.

Operations

Operations continue to run smoothly, with time lost (year-to-date) around 3% (comprising 1% equipment faults and 2% high wind).

Planning for a two-week shutdown in November continues, with the main activities being the refurbishment of the translator drive system, replacement of the focus-cabin hoist and preparatory work for the installation of the new seven-beam Methanol Multibeam receiver. (At the time of writing it appears that the full commissioning of the Methanol Multibeam receiver will be delayed until January).

A longer shutdown, of four to five weeks is planned for April 2006 to refurbish the Azimuth gearboxes. This work will include replacement of all original gears and pinions in these boxes. Most of the gearbox components have run essentially untouched since 1961. It is also planned to remove the 20-cm Multibeam receiver during this shutdown to complete its refurbishment. This work will comprise replacement of all remaining original low noise amplifiers (LNAs), and some modifications to the refrigeration system. The receiver is expected to be out of service for three to four months.

Receivers

Completion of the Methanol Multibeam receiver in time with scheduled delivery on 15 November now looks unlikely, owing to unforeseen delays in construction. Preparatory installation work will proceed in November, but full commissioning will be delayed until January.

The 20-cm Multibeam receiver continues to exhibit instabilities in three or four channels, but no further deterioration has been seen in recent months. These instabilities affect spectral-line users relatively lightly but pulsar search observations are more heavily affected. The problems are evidently due to microphonic instabilities in some of the older (original) LNAs, all of which will be replaced in or after April 2006.

The analogue pulsar filterbank has been rejigged slightly to allow an increased bandwidth of 864 MHz at 3-MHz resolution (centre beam only). The improved system has been used successfully to search for highly dispersed pulsars near the Galactic Centre at both 10 cm and 3 cm.

The MARS (3 cm) receiver was trialled recently with a interim conversion system to deliver approximately 1-GHz bandwidth (8.0 – 8.9 GHz), as opposed to the 400 MHz of bandwidth previously available. Plans are in hand to rebuild the new system for routine use in 2006.

A proposal to construct a new K-band (16 – 26 GHz) receiver has formally been approved, and a full project plan is now in process. The present estimate is for a two-year construction time, approximately. The receiver will follow the highly-successful design of the Compact Array 13-mm receivers as closely as possible, and is expected to deliver a 4 or 5 dB improvement over the existing K-band receiver at Parkes as well as greatly increased frequency coverage.

Backends

The wideband correlator (WBC) continues to work well, apart from fundamental limitations in timing fast pulsars (P < 20 ms). These limitations are mostly in the form of periodic artifacts in the amplitude versus pulse phase domain, which are suspected to arise from small differences between the individual correlator chips at short pulsar periods.

The Digital Filterbank Mark 1 (DFB1) continues to work very well, with none of the artifacts at short periods that affect the WBC. This prototype is restricted to the single bandwidth of 256 GHz, and also has some time resolution limitations for fast pulsars. The Mark 2 version of the DFB expected later this year will have 512 MHz maximum bandwidth and time resolution limits meeting the original specification. An upgrade to the full design bandwidth of 1 GHz is not expected until the April 2006 semester.

It is now possible to run the DFB and WBC in parallel using the TCS observing program, though with a little extra complexity in observing.

Upgraded Observatory network access

All is in readiness at the Observatory for arrival of a new broadband fibre-link, which is expected at anytime in the next few months. This connection will initially provide a 1 Gbit/s external data link, compared to the existing link of 512 kbit/s (or .0005 Gbit/s) however the new link will have a total capacity of > 50 Gbit /s if fully utilised. Similar link upgrades at Narrabri and Mopra will follow close behind, providing greatly expanded capabilities for e-VLBI. The highly successful VLBI observations of the Huygens probe in January provided a tantalising taste of what could become routine in the future with the faster links replacing chartered aircraft!

Staff

Lewis Ball has accepted a position as Deputy Director at Marsfield, effective from July 2005. We wish him every success in his new post. Lewis has remained a regular visitor to the site since July a presence we are only too happy to encourage!

Gina Spratt was delivered of a healthy baby boy, Jack, on 19 July and is currently on maternity leave. Gina is expected to return to work on a part-time basis in October, and all here are awaiting her return with eager anticipation.

Tom Lees is now back at work full-time following his successful shoulder surgery last year.

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