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ATCA Release notes for 2023APR

Staged Schedule Release: This semester, due to the significant uncertainty about the BIGCAT installation timeline, the schedule will be released in stages. The first release covers the period from April 1 to July 31. The entire semester has been provisionally scheduled, so if your grade is above the cutoff but you have not been scheduled in the period covered by the first release, your time has been allocated later in the semester. If BIGCAT is installed before your observations have been carried out, we will get in touch with you.

The schedule covering the period after July 31 was released as version 4 on May 1, when it became clear that BIGCAT would not be installed in this semester.

ATCA observing: ATCA observations may be conducted by trained observers at any location, including the Paul Wild Observatory, the Marsfield Science Operations Centre (SOC) or remotely.

To book on-site accommodation at either the observatory or Marsfield lodge, or just to register that you plan on observing at the SOC without requiring accommodation, please visit our online booking system, and make your booking at least two weeks in advance.

First-time observers are required to undergo a basic online training program, to learn the fundamentals of observing with the ATCA. Observers with prior experience are also welcome to participate in this training program.

This semester, we will be moving away from having a Duty Astronomer, to a system where each project has their own Observing Expert who can provide support before, during and after observations.

To learn more about our new basic training and the Observing Expert model, please visit the ATNF support page.

Observing experts (OEs) for each project this semester will be contacted by the observatory on or before March 15. Each OE will be informed of their duties and responsibilities for their project, and given instructions for how to perform their role.

Registration to observe, or to undergo training, or to book accommodation will require you to have an ATNF UNIX account. If you need to obtain an account, please use the online request form. Please note that it may take several business days to process this request, so please make your request well in advance of your training or observing.

CABB modes: Only the following CABB modes will be available for the 2023APR semester:

  1. the 1MHz continuum ("no zooms") mode,
  2. the 1MHz zooms mode (1M-0.5k), with up to 16 zoom bands per IF available,
  3. the 64MHz mode (64M-32k), which provides 32 channels of 64MHz bandwidth and up to 16 zoom bands (each having 2048 channels across it) in each IF
  4. the "hybrid" mode, with 2048 x 1MHz channels in IF1 (and no zooms) and 32 x 64MHz channels in IF2 (with zooms), and
  5. the VLBI tied-array mode.

See the CABB webpage for more details. CABB mode changes are mostly routine, except for changes to the 1MHz zoom mode, 64 MHz zoom mode, and hybrid mode, which require approximately one hour: this mode change is done by local staff or suitably trained others. In the graphical version of the schedule the requested CABB mode is shown in the top right corner of each block.

The 64 MHz and 1 MHz zooms modes are degraded due to bad blocks in both IFs. In IF1, blocks 3, 12 and 15 do not correctly form zooms, and in IF2 blocks 22, 23, 25 and 29 are also faulty. These faults mean that 3 zooms in IF1 and 4 zooms in IF2 cannot be trusted to provide useful data. Unfortunately it is not possible before testing to know which of your scheduled zooms might use these blocks, and so if you plan on using zooms this semester, please reach out to your observing expert well in advance, and/or to observatory staff.

Blocks 3 and 25 are always faulty in the pulsar binning mode also, but because they create large blocks of faulty channels in the continuum bands, the pulsar binning mode is no longer offered.

ATCA portal: The portal is a web-based tool that enables the observers to book in advance for observing blocks and to register as the current observer-in-charge. It also provides alerts, contact details, and a improved chat facility over that previously used in the ATCA observing VNC session. More details are available from the ATCA Users Guide. First-time users should refer to the ATCA Portal Beginners Guide.

ATCA Legacy Projects: CSIRO Astronomy and Space Science implemented a program of ATCA Legacy Projects starting from the 2016OCT semester. Legacy Projects are large, coherent science investigations, not reproducible by any combination of smaller projects, that generate data of general and lasting importance to the broad astronomy community. More details are available from the Legacy Project webpage. The call for Expressions of Interest proposed that Legacy Projects would be supported at the level of 25% of the available observing time. As there was some uncertainty over the funding of the ATCA into the future, the TAC was advised that ATNF would be willing to support Legacy Projects at a higher level.

The highest priority project C3132, "GAMA Legacy ATCA Southern Survey (GLASS): A Legacy 4cm Survey of the GAMA G23 Field", completed its observations in the 2019OCT semester. The other high-priority project C3157, "Imaging Galaxies Intergalactic and Nearby Environment (IMAGINE)", completed its survey in 2020OCT. The project C3145, "Star Formation in the Southern Hemisphere (StarFISH)", completed its survey in 2022APR.

No ATCA Legacy project requested time this semester.

Radio Frequency Interference (RFI): There is a strong emitter in the 16cm band in the 2630-2670 MHz range, a previously relatively clear part of the spectrum often used by 16cm-band observers for their delay calibration. Instructions for dealing with this are are available from the ATCA Current Issues webpage. RFI in the 16cm band also causes the sampler statistics to fluctuate, and the automatic attenuator setting often does not work. A set of standard attenuator settings for the 16cm band has been determined and these can be manually set -- see section 3.2.2 of the ATCA User Guide for more details. (If they have been set by a previous observer, it may not be necessary to set them again.)

There is also some RFI in the 15mm band in the frequency ranges 17.7--18.2 GHz, 18.8--19.3 GHz and 19.7--20.2 GHz which arises from a geostationary satellite and is stronger towards equatorial declinations. See the ATCA Current Issues webpage for more information.

RFI in the 16cm band cannot yet be mitigated on-line, but a mode in the correlator allows observers to more easily mask its effect on the diagnostic visibilities, using median averaging. Instructions on how to do this can be found from the ATCA Current Issues webpage.

NAPA Proposals: A number of NAPA (Non A Priori Assignable) proposals have been submitted for ATCA in 2023APR. We have a policy for dealing with NAPA over-rides, intended to ensure highly time-critical projects can be scheduled on the telescope. For the 2023APR semester, any NAPA which received a grade equal to or higher than the grade at which most of the projects got most of their time, will be able to over-ride any scheduled project. For this semester, all twenty-three NAPA projects meet this criteria.

If triggered, observatory staff will discuss with the proposers the best time for the over-ride to occur, which may not necessarily involve any project being displaced. Requests to trigger a NAPA proposal can be made by emailing the ATNF alert group, as described here.

Any observations displaced by a NAPA will be rescheduled if possible, but this is not guaranteed.

There are two NAPA projects that are authorised to use the rapid response service. Rapid response over-rides may occur at any time without staff or observer intervention.

Investigators triggering NAPAs are reminded that claim staking is not permitted under ATNF policy.

In order to minimise the impact of multiple competing triggers to observe the same event, the TAC has recommended that we encourage data sharing between NAPA teams who nominate to observe the same coordinates with the same receiver configuration and observing strategy. Observatory staff will discuss this arrangement with the affected teams should this situation arise.

Green Time: Green time should be requested through the Portal. Instructions for doing this can be found in the "Book" tab in the Portal. Requests for green time can be made at any time during the semester, but the final allocation will not be made until 1 week beforehand.

If you are requesting green time for a project that was not ranked by the TAC for this semester, please also email Jamie Stevens ( with a summary of what you are requesting to observe.

Only projects explicitly approved and that appear in the Portal schedule may be observed on the telescope. Under no circumstances can the telescope be used without prior permission from the Directors or the scheduler.

Daylight Saving: Daylight saving in New South Wales will end at 3:00am (AEDT) on Sunday, 2nd April 2023, when clocks will be put back one hour. AEST is 10 hours ahead of UTC. Daylight saving in New South Wales will start again at 2:00am (AEST) on the first Sunday in October 2023.

Public Holidays:

  • Good Friday (Aus) Friday Apr 7 2023
  • Easter Sunday (Aus) Sunday Apr 8 2023
  • Easter Monday (Aus) Monday Apr 10 2023
  • Anzac Day (Aus) Tuesday Apr 25 2023
  • King's Birthday (NSW) Monday Jun 12 2023

Version history: Version 1 of the schedule, covering April 1 to August 1, was released on 2023 March 1.
Version 2 of the schedule was released on 2023 March 29. This version moved some projects in April and early May to accommodate some global VLBI observations.
Version 3 of the schedule was released on 2023 April 11. This version changed the 6C configuration to a 6D, to prevent the use of stations without mains power.
Version 4 of the schedule was released on 2023 May 1. This version was for the full semester, with some other minor changes.

Generated: Jamie Stevens (1-may-2023)