Parkes report

Steering Committee visit

The Observatory hosted the ATNF Steering Committee (ATSC) over 14 – 15 April, using the Quarters facilities. A very enjoyable dinner for ATSC members and visitors was provided on the night of the 14th by the Dish Cafe. The visit featured the obligatory "hayride" for the Committee, and a visit to the focus cabin for the more enthusiastic, including new ATSC members Brett Biddington and Matthew Colless, along with the illustrious Bob Frater (making his first return to the focus cabin in many years). Many thanks to all staff for making the visit such a success.

Operations

Telescope operations this year have continued to be largely trouble free, with less than 1% of time lost to equipment faults in the year to date. Lost time due to wind is currently at 2.5% as the usual calmer conditions typical of the middle of the year prevail. A recent intermittent problem with the focus-cabin receiver translator caused several hours' lost time and several sleepless nights for technical staff. The fault was eventually identified as leakage to ground in a filtered connector — part of the system that had not been touched in seven years.

Receivers

Construction of the new seven-beam "methanol multibeam" receiver is proceeding on schedule for commissioning in October this year and is advertised as available for general observing from January 2006. Technical specifications are summarised in the Parkes Users Guide. The receiver will be commissioned with a single-frequency LO system. A second LO chain will be added as resources permit over the following months.

As has been flagged for some time, a second-phase refurbishment of the 20-cm multibeam receiver is being planned, for some time in the next six to 12 months. The main reason for the refurbishment is to replace all remaining original low noise amplifiers (LNAs), several of which are exhibiting instabilities that are proving deleterious to pulsar searching and, to a lesser extent, spectral-line observing (this list now includes channels 11A, 11B ,12B and 13B). Any other maintenance issues of a pressing nature that come to light once the package is disassembled will also be addressed. An upgrade of the cryogenic refrigerators is also being contemplated, subject to the results of further tests.

It is expected that the refurbishment will take approximately three to four months. The refurbishment will be scheduled with user requirements and demands foremost in mind. First thoughts were to begin the work in late 2005, but this could have a serious impact on some existing long-term projects. Undertaking the work towards the end of the 2005OCT Semester may be a better option.

A project concept document has been submitted for a new 12-mm receiver package for Parkes. The new package will employ the same LNAs and orthomode transducers as the Compact Array 12-mm systems. A possible option is to build the receiver as a dual-horn system to double its efficiency for position-switching observations; however this increases the complexity, cost and construction time. With the newly-designed and manufactured feed illuminating the full 54-m high-performance aperture at Parkes the new system should deliver approximately 4 dB of extra sensitivity over the old system.

Owing to the projected high demand in the upcoming semester for both of the large multibeam receivers (20-cm multibeam and the methanol multibeam), a study is being made of the feasibility of allowing the methanol multibeam to be mounted in either position on the receiver translator. If feasible, this option will give greater flexibility in scheduling observations with both multibeam receivers in the same semester. Such flexibility would come at some cost in the availability of the 10/50-cm receiver and other packages, but overall should allow a better match of the schedule to the scientific merits of the proposal pool.

Backends

Modifications to the conversion system were completed in May allowing the full 1-GHz bandwidth of the 10-cm receiver to be exploited. The 1-GHz bandpass sampled by the wideband correlator is now flat to within 3 – 4 dB across 900 MHz (2650 – 3550 MHz). At present the modifications have been made only to the first half of the conversion system — modified modules for the second frequency chain are under construction.

A problem with the wideband correlator (WBC) samplers was found and rectified in May. This problem is believed to have been exacerbating the "residual ripple" problem in some WBC observations. Subsequent tests have shown a distinct improvement.

Construction of the prototype of the Digital Filterbank (DFB) is close to complete and installation is scheduled for the second half of June. The fully-functional DFB is expected to be operational late this year.

Brief specifications of the prototype and final DFBs are given in the Parkes User Guide, available through the Parkes home page under "Documentation".

Site changes

The new bus is on the right and the old bus is on the left, with the dish in the background.

The upgrade of the worst section of the 6-km road to the site started in November was completed somewhat behind schedule in April, owing partly to delays with rain and problems in sourcing of gravel. The upgraded section has vastly improved the overall quality of the road. The upgrade was jointly funded by CSIRO and the Parkes Shire Council, with the Council carrying out the work.

Work progresses on the new kitchen at the quarters, with construction now complete and fitting-out starting in earnest.

A new shed has been erected on site adjacent to the existing workshop and carpenter's shop. The new shed will serve a number of functions including as a workshop for welding, grinding and cleaning and other activities which are not wholly compatible with the precise machining and milling that is carried on the main workshop. The shed will also garage site vehicles, and provide covered storage for the many raw materials that presently have to sit outside.

The Observatory has a new bus which arrived on site on Monday, 6 June.

Broadband links

The prospect of a new broadband (> 1Gb/s) data link to the Observatory has taken a major step forward with the letting of a contract by AARNet to run the optical fibre connection from the Observatory to their backbone fibre, west of the Newell Highway. The contractors expect to finish laying and terminating the fibre tails in early July. The Observatory is providing cable pits and conduit for the last 100 m from the property boundary to the tower.

Visitors Centre

A new program for the 3-D theatre featuring a 3-D "virtual tour" through the telescope is currently in final production at the Swinburne University of Technology. Pre-release screenings at the Visitors Centre have generated a lot of positive feedback and all are keenly awaiting arrival of the finished product. Thanks go the Matthew Bailes and his team at Swinburn University for turning this long-awaited dream into reality (or a virtual reality at any rate).

On Sunday 24 April of the Anzac weekend, the Observatory staged a "Twilight Concert at the Dish". A sound stage was erected in the paddock adjacent to the Visitors Centre and ticket holders were treated to a memorable and varied program from students of the Conservatorium of Music. The Dish Cafe catered for the event, which also showcased the products of the local organic wine producer, Rosnay Wines. All of the 200 tickets were snapped up and the feedback has been uniformly enthusiastic. Plans for a similar event in the near future are already being drawn up.

The Visitors Centre is the venue for a monthly meeting of the Central West Astronomical Society. This society was founded in 2002 and aims to foster and promote astronomy awareness in the Central West of NSW. In addition to the regular monthly meetings, the society hosts dark-sky viewing nights at a site in Cookamidgera, about 10 km south of Parkes.

This year the Society continued to attract a wide range of guest speakers to its monthly meetings. They included Colin Bembrick (noted amateur), Alan Dyer (Canadian Sky and Telescope magazine editor), John Dobson (astronomy legend), Dr John O'Byrne (Sydney University first-year Physics Director) and Prof Joel Weisberg (Carleton College). For more information on the CWAS and its activities, see the following URL: www.cwas.org.au/ .

The Society's annual AstroFest will be held throughout the month of July. A feature of this astronomy festival is the "David Malin Awards" astrophotography exhibition and competition. Astrophotographs taken by amateurs from throughout Australia will be exhibited in the Observatory's Visitors Centre for the entire month. Last year over 14,000 people viewed the exhibition. Inspired by this success, the exhibition will this year tour the country to selected venues beginning with Sydney Observatory in August.

The AstroFest's two-day conference will be held on the weekend of the 16 – 17 July. A stellar array of speakers is lined up. Two of the highlights of the conference will be the "John Bolton Lecture" on Saturday and the Grote Reber Memorial lecture on Sunday. The AstroFest is open to anybody with an interest in astronomy. For more information on the CWAS AstroFest and the "David Malin Awards" see: www.parkes.atnf.csiro.au/events/astrofest/.

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