Gemini's Report on MAXAT - the Maximum Aperture Telescope

Final Reports: Madison (1998), Woods Hole (1999)

The AURA Coordinating Council of Observatory Directors has recommended that AURA conduct an in depth examination of the science and technical issues surrounding the possible construction of an extremely large aperture (30-50 meter) ground based telescope. Such a facility could play a crucial role in compleme nting future space based observatories such as the Next Generation Space Telescope and other ground based observatories such as Keck, the Very Large Telescope, and Gemini.

In carrying out this charge, AURA intends to convene a small study group to fully develop the scientific case for a Maximum Aperture Telescope as well as some of the crucial performance specifications that will guide its development. The study group was be chaired by Dr. Jay Gallagher of the University of Wisconsin, and met in a workshop type format on August 28 and 29 in Madison, Wisconsin.

Charter | Purpose and Format | Questions | Agenda | Papers


The current generation of 8-10 meter telescopes represents the state of the art for ground based observing for the foreseeable future. The fifth in a series of Decadal Reviews, which will commence towards the end of 1998, will examine the scientific advances, themes, and technologies that will dominate astronomy for the beginning of the next millennium. The Review will result in a science strategy which will optimize the observing capabilities of space based and ground based facilities and, in particular, these large aperture telescopes.

The current generation of large aperture telescopes is just beginning routine operation and, although major discoveries have already been realized, their full scientific potential and operational modes have not yet matured. However, in order to avoid a de facto moratorium on potential future advances in ground based astronomy, it is critical that the Decadal Review address the scientific, technological, and cost related factors that should be considered in defining the next major step.


This workshop is proposed to operate under the sponsorship of AURA as an activity of the AURA Coordinating Council of Observatory Directors (ACCORD). It is intended to represent the views of the astronomy research community towards the role that an Maximum Aperture Telescope should play in the future of ground based astronomy. The intent of AURA and ACCORD is that the results of this workshop be considered by the next Decadal Review in formulating recommendations for the future.

The intent of the workshop is to review the scientific case for a telescope beyond the current generation, the technology drivers that will define the configuration and approach towards constructing such a telescope. In carrying out the workshop, ACCORD will appoint a small study group possessing the necessary expertise and experience that will guide the discussion and synthesize the results.


The workshop will not assume any particular configuration or technological approach towards a Maximum Aperture Telescope (MAXAT). However, it is assumed that any such new telescope must operate in the visible and infrared and must operate at the diffraction limit in order to make significant advances and justify the investment. Within the overall architecture for the future of astronomical research, such a facility must directly complement the Next Generation Space Telescope and fill a definable niche in the overall hierarchy of large aperture telescopes including the Very Large Telescope, Keck, and Gemini. Thus far, apertures in the 30-50 meter range have been proposed in characterizing the MAXAT class range.

Illustrative questions the workshop could address include the following:



Thursday, August 27, 1998

18:00-20:00 Welcoming Reception


Friday, August 28, 1998

08:00 Meet in hotel lobby for transportation to Chamberlin and Sterling Halls, University of Wisconsin-Madison

08:30 Continental Breakfast

08:50 Introductory Remarks

09:00 Basic Ideas for Very Large Aperture Telescopes (M. Mountain)

09:40 High Angular Resolution with Large Telescopes (R. Angel)

10:10 Interferometry and High Angular Resolution (S. Ridgway)

10:30 Break

10:45 Extremely Large Spectroscopic Telescopes (L. Ramsey)

11:10 Arecibo Model for Large O/IR Telescopes (T. Herter)

11:30 Baseline Model for an Extremely Large Aperture Telescope (J. Gallagher)

[This is the straw model which the science groups will be working with during their discussions]

12:15 Lunch (Memorial Union)

15:30 Break

16:30 Progress Reports from Science Groups

18:30 Dinner


Saturday, August 29, 1998

08:00 Continental Breakfast

08:30 Review of Concerns and Objectives of Science Group Reports

08:50 Finalize Science Group Reports -- Science Discussion Groups

10:15 Break

10:30 Science Group Reports

12:00 Lunch (Austins Restaurant)

13:00 Identification of Science Themes (J. Gallagher)

Refine Telescope Characteristics--Technology, Science Trade-offs (R. Bless)

Definition of Minimal Performance Specifications for a Very Large Optical/IR Ground-Based Telescope

13:30 Science Discussion Groups

-Cosmology/Large Scale Structure (M. Bershady)

-Galaxies/AGN (E. Skillman)

-Stellar and Planetary Astrophysics (S. Strom)

- Technology (R. Angel/J. Oschmann)

15:00 Break

15:15 Proposed MAXAT Attributes, and an Outline and Discussion of Next Steps (J. Gallagher, W. Smith)

17:00 Adjourn


Relevant Papers