1. Welcome to the 4th NAIC-NRAO School on Single Dish Radio Astronomy

2. Arecibo is an icon of single dish radio astronomy, the largest and most sensitive telescope in the world. It is currently executing three major surveys using the ALFA seven-feed L-band array, focussing respectively on pulsars, the galactic interstellar medium, and extra-galactic HI respectively.

3. The GBT is in my opinion now the premiere fully-steerable single-dish centimeter radio telescope in the world. It is currently working at frequencies up to 50GHz, with plans to get up to 115GHz, and has a wide range of instrumentation

4. Moving up in frequency, the JCMT is an example of one of a number of millimeter telescopes which came on line in the late eighties and early nineties. The impact of the first SCUBA camera on the 15m JCMT has been immense. In particular, it has led to major advances in our understanding of the how planets, stars and galaxies form. In cosmology SCUBA has been described as having an impact "as big or bigger than the Hubble Space Telescope" having shown that the far infrared/sub-millimetre background is in fact composed of the combined light from distant dusty galaxies.

5. The Large Millimeter Telescope (LMT), is a 50-m diameter single-dish telescope optimized for astronomical observations at millimeter wavelengths (0.85 mm < λ < 4 mm). It should come on line in the next couple of years, and already has an impressive suite of instrumentation ready for it.

6. The APEX telescope, designed to work at sub-millimetre wavelengths, in the 0.2 to 1.5 mm range, passed its Science Verification phase in July 2005 successfully (see ESO PR 18/05 and ESO PR 25/05), and since then is performing regular science observations. It is located on the 5100 m high Chajnantor plateau in the Atacama Desert (Chile), probably the driest place on Earth. It is a collaborative effort between the Max Planck Institute for Radio Astronomy, ESO and the Onsala Space Observatory (Sweden). With its precise antenna and large collecting area, APEX provides, at this exceptional location, unprecedented access to a whole new domain in astronomical observations. Indeed, millimetre and sub-millimetre astronomy opens exciting new possibilities in the study of the first galaxies to have formed in the Universe and of the formation processes of stars and planets. It also allows astronomers to study the chemistry and physical conditions of molecular clouds, that is, dense regions of gas and dust in which new stars are forming. APEX is the pathfinder to the ALMA project. It is a modified ALMA prototype antenna and is located at the future site of the ALMA observatory. ALMA will consist of a giant array of 12-m antennas separated by baselines of up to 14 km and is expected to gradually start operation by the end of the decade. It will bring to sub-millimetre astronomy the aperture synthesis techniques of radio astronomy, enabling precision imaging to be done on sub-arcsecond angular scales, and will complement the ESO VLT/VLTI observatory.

7. The initial studies of the CCAT were carried out by Caltech, Cornell, and JPL. Now three other institutions have joined a consortium to construct and operate the telescope.
Cornell University, Astronomy Department
California Institute of Technology, Submillimeter Astrophysics
Jet Propulsion Laboratory
University of Colorado
University of British Columbia
UK Astronomy Technology Centre
Aperture: 25 meter class is significantly larger than APEX, SMT, CSO or JCMT – ensures that it is not confusion limited in exposures of 24 hours or less.
Water Vapor Burden: Need consistently lower burden than 1 mm to reach the short submm windows
Surface Accuracy: Desire high surface accuracy (~ 12 um rms) to obtain good efficiency in the 200 um window (1.5 THz)
Field of View: Faint source surveys a forte – therefore requires large FOV > 5’ which could be populated with 10,000 element arrays.