Gemini Preprint #11

What is beyond 8m-10m class telescopes and the VLT-I: a Very Large Imaging Array for Groundbased Infrared and Optical Astronomy?

M. Mountain
Gemini 8m Telescopes Project, 950 N. Cherry Ave., Tucson AZ 85719


The tremendous growth in the building of large 8m and 10m telescopes, which give substantial gains in sensitivity over the current 4m telescopes, presents a significant challenge to the builder of a future 21st century groundbased telescope. To try and explore the possible scientific motivations that may drive a future groundbased facility, I have chosen a current observational project whose completion is beyond the capabilities of our new generation of telescopes. By examining what is required of a groundbased facility to undertake spectroscopy on the majority of the objects in the Hubble Deep Field (HDF), it becomes apparent this project will need a Very Large Imaging Infrared Array (VLIA) or a 50m telescope. The main conclusion of this comparison is that any groundbased facility capable of undertaking this project is likely to cost at least one billion dollars. The choice between the two differing approaches should therefore be driven by the scientific aspirations of the 21st century community of astronomers. Superficially, the "scientific edge" probably belongs to the VLIA facility, with its ability to probe structures at infrared wavelengths down to the milli-arcsecond scale. The more profound issue is whether it is time for groundbased astronomers to begin looking to space for the placement of their next 21st century telescope.

Appears in Proc. SPIE 2871, "Optical Telescopes of Today and Tomorrow".

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Ruth A. Kneale / / November 15, 1996