Rules and Guidelines for Hosting IAU GAs

Every three years the International Astronomical Union (IAU) has its General Assembly (GA) where it offers a rich scientific program to its members and conducts its administrative business. The proceedings of the scientific program are documented in the IAU Highlights of Astronomy (from 1968 until 2012) and in the Transactions A Proceedings of each IAU GA; the administrative business is documented in the Transactions B Proceedings of each GA.


An IAU General Assembly (GA) is scheduled over 12 days, from Monday through Friday over two weeks, with registration starting on the preceding Sunday. The plenary Opening Session is held on the Monday afternoon or Tuesday afternoon of the first week; the plenary Closing Session is held on the Thursday afternoon or Friday afternoon of the second week. The exact dates may be set depending on local arrangements and are to be discussed with the IAU.

The scientific program normally comprises six Symposia, each of 3-days in duration and spread over three working days, because of the two administrative Sessions of the GA per se. Three Symposia are scheduled during the first week, and three during the second week. Also held during the 10 working days are some 12-18 Focus Meetings, each lasting 1-2 days, and 9 Division Meetings, each lasting 2 days.

The selection of Symposia and Focus Meetings is made by the IAU Executive Committee (EC), in consultation with the IAU Division Presidents (DPs).

Each Symposium and Focus Meeting is organized by its own international Scientific Organizing Committee (SOC), which liaises with the host's NOC/LOC through designated representatives.

Four Invited Discourses (ID) by distinguished scientists are held as plenary science sessions, open to all participants and accompanying guests, during two evenings of the first week, and two evenings of the second week.

The above scientific events and associated events are open to all registered participants of the GA.

During the GA a large number of administrative and business meetings are being held. The EC has its own administrative meetings, usually lasting four days in several sessions. The EC meets with the National Representatives, the Finance Committee, the Special Nominating Committee, the Membership Commitee, the Resolutions Committee and the Division Presidents. The Divisions, Commissions, and Working Groups have their own business meetings, some of those also hosting scientific discussions.

All of the above-mentioned activities require a program of 10 working days with up to 16 parallel sessions.


The IAU follows the regulations of the International Science Council and concurs with the actions undertaken by their Standing Committee on Freedom in the Conduct of Science on non-discrimination and universality of science.


Recent GAs have been attended by 2000-2500 participants. Although the GA program should be sufficiently attractive to attract all participants of the whole GA program, not all will stay for the entire 12 days, depending on a participant's interest in the various individual sessions. Estimates based on past GAs indicate that about 1/3 of the participants attend one of the two weeks, and 1/3 attend both weeks.

Minimum room requirements are:

  • One major hall seating at least 2500 persons, required for the GA plenary sessions (Opening and Closing Ceremonies and 2 Business Sessions), plus 4 evenings (IDs).
  • Three lecture rooms seating 500-600 persons, required during all 10 working days of the GA for the Symposia and the larger Focus Meetings.
  • Four lecture rooms seating 250-400 persons, required during eight working days, for the smaller Focus Meetings and any last-minute sessions.
  • Ten smaller lecture rooms seating 100-120 persons, required for the business meetings of Divisions, Commissions and Working Groups. These can serve also for the larger administrative meetings mentioned above. They need to be available the full period of the GA.
  • One room seating 120 persons for meetings of the Executive Committee with the National Representatives, the Nominating Committee, the Finance Committee and the Resolutions Committee.
  • Two rehearsal rooms for presentations using slides and digital projectors. Rehearsals require on-the-spot assistance of specialists concerning all specialized audio-visual equipment needed in the conference rooms.

The IAU staff and functions require the following office space:

  • Secretariat: two rooms
  • President: one room
  • President-Elect: one room
  • General Secretary: one room seating 20 persons
  • Assistant General Secretary: one room with two desks
  • IAU Grant distribution: one room
  • Finance Committee: one room
  • Resolutions Committee: one room
  • Young Astronomers: one room
  • Media: one Press Room seating 20 persons, one Press Room seating 30 persons and one Press Interview Room seating 10 persons
  • GA Newspaper: one room seating at least three persons and their equipment.
  • All these offices need telephone and computer network connections, with additional needs for the Secretariat and Press Room (telephone, fax, copying machine, printer etc.), as well as Press Conference Room (screen and video projector).

Wireless modern broadband Internet access should be available throughout the GA venue. In addition, fixed Ethernet broadband Internet access should be available in the Secretariat and Press Office rooms (20 connections).

Preference should be given to venues offering the possibility to hold the entire General Assembly under one roof.


The Host shall, at least 1.5 years in advance, create and maintain a GA web site, providing all necessary information for the GA, electronic registration, electronic hotel booking, and electronic ordering of GA proceedings.

The Host shall produce the Program Book for the General Assembly and the Abstract Book for the science meetings. The manuscripts for these books shall be provided by the IAU, no later than four weeks before the General Assembly. These books must also be available in electronic form, to allow for last-minute updates and information.

The Host will prepare different categories of badges, in consultation with the IAU EC.

Upon arrival, all participants will receive from the Host a satchel (with attached name badge) containing at least:

  • a Name Badge,
  • a Receipt for the Registration Fee,
  • the Program Book,
  • the Abstract Book,
  • local maps and other relevant information.

The Host offers a Welcoming Reception for all participants on the evening of the First Session of the GA, at no cost to the participants.

The Host is responsible for the preparation, printing and distribution of the daily GA Newspaper in electronic or print form. A copy of all the daily printed newspapers or daily digitized PDF versions (in at least 150 DPI) must be delivered to the IAU Secretariat within two weeks of the end date of the GA.

Coffee and tea during breaks are to be included in the Registration fee.

Social events, e.g., closing dinner, concerts, post-meeting tours or tours on the free Saturday and Sunday are optional; an additional charge for them is acceptable if necessary.

The Host is expected to offer all normal services associated with the running of a large international scientific meeting, like a Registration Desk, an Information Desk, a Travel Desk, a Hotel Booking desk, and Bank Services.


The Gruber Foundation (TGF) offers its Cosmology Prize annually to an accomplished astronomer. The IAU provides members for the Advisory Board of the TGF Cosmology Prize. In the year of a GA, this Prize and one TGF Fellowship are awarded during the GA Opening Ceremony, in coordination with the IAU. To celebrate further, the TGF normally organizes a reception and private dinner, in consultation with the Host and the IAU.

It is customary that the Host country takes advantage of the presence at the GA of numerous highly qualified specialists in astronomy and astrophysics, by organizing events with their collaboration for the general public, in particular teachers.


In keeping with the strong desire of the IAU to allow as many astronomers as possible to attend the GA regardless of the financial conditions at their home institutes, availability of cheap accommodation is an important consideration in the selection of a venue for an IAU GA. Cheap accommodation can include university student dormitory rooms, assuming that the GA is held outside university terms.

While university dormitories may offer single rooms only, a good supply of cheap hotel double rooms (at least 500-1000) should be available, with the option of advance block booking. Again, most rooms should be in the low-to-middle price range; very few astronomers require luxury rooms.

Similarly, low-cost restaurants should be available in large quantity nearby, including quick and cheap facilities for informal lunch meetings.

Easy access and transportation between hotels, dormitories, and the venue of an IAU GA is highly desirable.


The governmental bodies of a Hosting country, as well as its astronomical institutions, must commit themselves to provide adequate financial contributions and guarantees to the organizing and running of an IAU General Assembly. In addition, an IAU GA will require extensive manpower support from the national astronomical communities, staff and students. An invitation to host an IAU GA must demonstrate such national interest and quantify the support to be offered.

The GA Host shall play an active role in promoting the GA, nationally and well as internationally, via a dedicated GA web site, posters, and live presentations at national and international astronomical meetings in the year leading up to the GA.

It is a sign of national support that the Host country's National Committee for Astronomy (NCA) has a good record of paying its annual membership dues to the IAU on time.


Representatives of the IAU Executive Committee will annually visit the Host during the three years before the GA to discuss GA matters on the spot.

In the course of the preparation of the GA, the IAU will make available for the Host its web site, and the email distribution list of its ~11,000 active members, to announce details about the GA, as well as a list of a large number of astronomical libraries and institutes.

The IAU will sponsor the scientific program of the GA by offering to a large number of participants IAU Travel Grants, to be allocated and selected, respectively, in accordance with its rules for distribution of these, upon recommendation by the SOCs of the main scientific events. The total IAU GA Travel Grant estimate is of the order of 250,000 EUR. This amount is not to be included in the budget to be offered by the Host.

The Registration Fee for the GA, a flat rate for all participants, needs the approval of the IAU EC as part of the acceptance of the invitation. The currently accepted ceiling is 600 EUR. Special categories of reduced fees may also be created (students, senior or retired participants, etc.).

The Hosts' NOC/LOC is responsible for all local financial arrangements of the GA, including the cost of the meeting venue and any assistance of a Professional Conference Organiser (PCO) or others in organising and running the GA. Apart from the income provided by the Registration Fee paid by the participating IAU members, invited participants and accompanying guests, and apart from the IAU support in announcing the meeting (mentioned above), the IAU does not provide a financial contribution to the operation of the GA.

The NOC/LOC will need to raise substantial additional funding from various sponsoring sources, to keep the registration fee below the accepted ceiling of 600 EUR.

The Host normally organizes an Exhibition, with exhibition space to be rented out to telescope-building companies, aerospace companies, computer companies, scientific publishers, research agencies, major observatories, etc. This Exhibition should provide income for the NOC/LOC, helping to cover its expenses. At this Exhibition, the Host is expected to offer, free of charge, adequate exhibition space to the IAU/OAD/OAO and to the host of the subsequent GA.

An invitation to host an IAU GA must include in its bid book a comprehensive draft budget, demonstrating sound financial conduct.


Based on the proposals received for hosting an IAU General Assembly , the IAU Executive Committee will select a first and second candidate at the GA being held 6 years before the proposed GA.

Immediately after the selection, the IAU will prepare a MoU specifying the responsibilities for the various elements discussed above. In the event that the candidate-Host should be unable to fulfill the specified conditions and to sign the MoU with the IAU within six months, negotiations will be taken up with the second candidate-Host.


Letters of intent proposing to host the IAU General Assembly in 2027 should reach the IAU GS before November 1, 2020.
The deadline for submitting to the GS bid books proposing to host the IAU General Assembly in 2027 is April 1, 2021.

OE, 22 April 2005 / Adapted: 17 January 2013 / Updated: 5 December 2014 / Updated: 12 December 2016/ Updated: 15 March 2019


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