4th APT meeting, Sydney, Australia 4-7/12/1995 ------------------------------------------------------------------- A. APT business meeting. 5/12/95 --------------------------------- Present: CHINA: Ye Shuhua (Shanghai), Wu Lin Da (Shanghai), Liu Xiang (Urumqi), Zheng Yong (Nanjing), Ca Jainqing (Xian), Qian Zhihan (Shanghai), Jiang Dong Rong (Shanghai) JAPAN: Makoto Inoue (NRO), Taizoh Yoshino (CRL), Koichi Yokoyama (NAOJ, Mizusawa) AUSTRALIA: Ron Ekers (ATNF), David Jauncey (ATNF), Tasso Tzioumis (ATNF), Peter McCulloch (U.Tas.), Victor Migenes (ATNF/DSN), Paul Harbison (Tidbinbilla/DSN) RUSSIA: A. Ipatov (IAA RAS) GERMANY: Hayo Hase (IfAG), James Cammbell (Geodetic Institute, U. Bonn), Erwin Groten (IPG-D) USA: John Bosworth (NASA, Goddard), Ben Chao (NASA/GSFC), Alan Whitney (Haystack) KOREA: Chang Hoon Lee (DRAO), In Sung Yim (DRAO) CANADA: Wayne Cannon (ISTS/SGL, York Uni.) EVN/JIVE: Harvey Butcher (EVN/NFRA), Maria Rioja (JIVE) Agenda: 1. Follow-up from Kyoto APT meeting September 1993 Minutes Action items 2. APT Membership NASA Deep Space Network Status Other countries 3. APT Activities so far establishing contacts dissemination of information on facilities science meetings science experiments (adhoc scheduling only) compatibility - nothing achieved 4. Future development of APT What can we learn from the EVN model? board of directors ? program committee ? technical working group ? Scheduling the network for astronomy experiments Reports from observatories on scheduling methods Allocate a block of time for APT experiments in 1995 Relationship to APSG (Asian Pacific Space Geodynamics) 5. Updated APT information (distributed at this meeting) Use of Internet/World Wide Web How to include Geodetic information? 6. Coordination with other networks EVN DSN 7. Next APT meeting Location Date Content 8. Technology compatibility issues recorders, translators, correlators, software 9. Sharing technology - coordination of activities Receivers, clocks ---------------------------------- 1. Minutes of previous meeting The minutes of the 2nd APT meeting, Kyoto, Japan, September 1993 were presented by Tzioumis and accepted by the meeting. Action items arising on membership and coordination of the APT are covered in other sections of this agenda and will be discussed there. 2. APT Membership - Brazil, SEST and Hartebeesthoek were invited to join the APT. - NASA/DSN - one membership with two representatives: Technical - V. Altunin Scientific - R. Preston - Other candidates are geodetic antennas i.e Kokee Park, NASA/USNO Santiago, Chile operated by NASA/University of Chile O'Higgins, Antarctica, operated by IfAG, Germany Most of the information for these exist in geodetic tables etc ACTION: Include O'Higgins information in tables. Provide WWW links to geodetic information. 3. APT activities Dissemination of information on facilities and establishing contacts proceeded as planned via the APT tables and email. On compatibility only the problems were highlighted. A list of the APT international programs (by D. Jauncey) is given below: APT International Astronomy/Astrometry Programs ----------------------------------------------- Program PI Co-Investigators -------------------------------------------------------- 5 GHz imaging survey China Aust., USA, South Africa SHEVE Imaging Aust/USA China, Japan, SA Mk3 Astrometry Aust/USA Japan, China, SA K4 Astrometry Japan Australia "Burst-mode" tests Japan Australia Pulsar Astrometry Australia South Africa Pre-launch surveys: 22 GHz Continuum US/Japan Australia 22 GHz Line Australia Japan, USA, China 1.7 GHz Line/Cont. Russia Aust., SA Radio Stars Australia China, Japan, USA, SA 4. Future --------- Harvey Butcher, EVN chairman, outlined the organisation of the EVN and discussion occurred for each item. i) Directors meeting: An EVN Directors meeting takes place once per year, to re-emphasise commitment and talk through current observational problems including money. Also plan for the future. These meeting are VERY IMPORTANT for the network. Mdme Ye suggested an APT "Board of directors" with rotating chairman who would host the annual meeting. In the ensuing discussion it was generally agreed that such a board would be very good for the APT. ACTION: Have a directors meeting at next APT Workshop. At this point, discussion also occurred on the rapid correlation for network feedback. In the EVN, this task is performed by the JIVE support scientists who correlate calibration data quickly and check the gains, phase jumps and general quality of the data. The feelings of the participants were positive but no decision was taken. ii) Program committee & scheduling for Astronomy EVN PC committee with members from local time assignment committees (TAC). There are also geodetic agreements. In answer to a question by Bosworth it was stated that in general this is collegial activity and no payment is involved. For each APT observatory, a description of current Time Assignment practice was given: -- R. Ekers for the ATNF, Australia, described the process for allocating time on the AT Compact Array and Parkes. Proposals are accepted for 4-month terms (about 75 proposals /term) and evaluated by TAC. For VLBI proposals, a priority is assigned by TAC and then passed to a VLBI sub-committee for coordination and scheduling. Fraction for VLBI is less than 30 days/year. More geodetic time may also be available on ATNF antennas. However, need longer term coordination to find common periods. Could be done through the VSOP interaction. -- Inoue for JNET (Nobeyama, Kagoshima, Mizusawa) + Kashima The PC is the same as for the 45m antenna. -- Yamamoto - Mizusawa geodetic station i.e. geodetic network scheduling. Allocated 1 year in advance -- Qian for China: Joint VLBI committee for Shanghai and Urumqi VLBI scheduling, to resolve conflicts with individual requests. -- Campbell for O'Higgins: Only operational twice per year, in February and June or October. Participation in astrometry is ok. An Astronomy program will need permission and satellite tracking decision. For observations in February 1996, schedule tentative particiaption by O'Higgins. ACTION: Ask for time on O'Higgins. -- Bosworth for NASA program: Schedule 1 year in advance. There is a "master schedule" which is finetuned in 3-month period. Coordinated by Nancy Vanderberg. There is a move to new philosophy to allow creation of new programs. Process is currently bounded by correlator time. ACTION: Letter to Ken Johnston, Copy John Bosworth re Kokee Park participation and Washington correlator availability. Suggestion from Ekers: Try to allocate block of time for APT observations. There was long discussion on the feasibility of such time allocation. It soon became evident that the most realistic system will be observations in the standard S/X VLBI band with the Mk3 network. The meeting decided to define an astrometric program for the APT session and find a common time. Decision: Schedule 3 days at end of June 1995. Program: Astrometry, 1-day geodesy, plus some astronomy by using radio stars. Participation possible by: Japan: Kashima, Mizusawa; Australia: Parkes, Hobart, DSN (may need pressure to get DSN time at Tidbinbilla); China: Shanghai, Urumqi; South Africa: Hartebeesthoek; Hawaii: Kokee Park; Chile: Santiago (keep informed). ACTION: On John Reynolds (ATNF VLBI scheduler) to find common date in this period. Discuss possibility of Program Committee at next APT meeting. iii) Technical Working Group (TWG) The EVN runs such a technical group for the exchange of technical information primarily on the VLBI hardware, identifying and fixing problems and coordinating upgrades. There was a "compatibility working group" but no progress was made and activities waned. Yoshino mentioned the IRIS working group in 1992, 93 with technical development centres at CRL, Haystack and VSOP and suggested that this could be combined with a TWG. Jauncey suggested that the APT setup a general TWG, not limited to VLBI but addressing general technical issues on radio astronomy. The scope will be to share technical information and people. After considerable discussion it was decided that a technical group should be setup. ACTION: Paul Harbison (DSN, Tidbinbilla) to come up with proposal. iv) Relationship to APSG Organisation parallel to APT but still developing. It was suggested that annual meeting may be at the same time with some time in common. Mdme Ye is the contact. ACTION: Suggestions and feelings to Mdme Ye. v) Newsletter Brief discussion to make a newsletter in the form of the summary of this meeting. No definite actions allocated. 5. Updated APT information ACTION: Tzioumis and Edwards to produce an APT homepage hosted at ATNF. 6. Coordination with other networks EVN - Key role for Chinese observatories since Shanghai and Urumqi are in both EVN and APT. Mdme Ye agreed for China to assume the coordinating role and avoid conflicts in schedule. mm-VLBI - Japan already participating in current network (Inoue) Space VLBI - there was a GVWG request for S-VLBI coordination in the APT region. No final decision. Deferred till after next S-VLBI meeting. DSN - Migenes suggested that an official request for time to DSN from the APT is needed, requesting time separate to host-country time and similar to the RASA program. ACTION: Generate letter to DSN. Ekers suggested that networks should come under some URSI/IAU body. Bosworth mentioned that geodesy is already under STSG. 7. Next APT meeting Jauncey offered to host the next meeting in Australia either Sydney or Hobart, in about 1 year's time. This will also involve the Australian Geodetic community. ACTION: Jauncey to coordinate arrangements for next APT meeting. ACTION: Tzioumis to produce minutes of current meeting. Items 8 & 9in the agenda were deferred to the General discussion next day. Agenda is shown below. General Discussion - Friday Oct 14, 1994, 10:00 -13:30 ------------------------------------------------------ AGENDA 1. Technology compatibility issues (Introduction by Wayne Cannon) Definition of future standards Tape copying Correlators with mixed systems Real time correlation 2. Compatibility in instrumentation needed for astronomy, astrometry, geodesy Difference between imaging and delay measurements Design criteria for future systems 3. How to develop future collaborations Information exchange Joint developments between Geodesy and Astronomy 4. How to handle the push for "user pays" Do we share facilities or charge for use? How will data conversion centres operate? 5. How we justify our science can we learn from experiences in other countries or other disciplines? 6. The need to focus our activities on well defined outcomes. Comments -------- The issues in the agenda above were vigorously debated in a long and wide-ranging discussion. A summary of this is beyond the scope of these minutes. However, one "action item" emerged form the compatibility discussion. To prevent incompatibilities in future VLBI systems, it was proposed that a ``standards'' committee be setup under international auspices, such as URSI and CSTG. Ekers offered to put this item on the URSI agenda. Harvey Butcher, the current EVN chairman, agreed to initiate such a committee. ACTION: Harvey Butcher to intitiate international standards committee on "generalised interfaces" for VLBI systems.