  New mass-produced, wide-field, small-aperture telescopes have the potential
to revolutionize ground-based astronomy by greatly reducing the cost of
collecting area. In this paper, we introduce a new class of large telescope
based on these advances: an all-sky, arcsecond-resolution, 1000-telescope array
which builds a simultaneously high-cadence and deep survey by observing the
entire sky all night. As a concrete example, we describe the Argus Array, a
5m-class telescope with an all-sky field of view and the ability to reach
extremely high cadences using low-noise CMOS detectors. Each 55 GPix Argus
exposure covers 20% of the entire sky to g=19.6 each minute and g=21.9 each
hour; a high-speed mode will allow sub-second survey cadences for short times.
Deep coadds will reach g=23.6 every five nights over 47% of the sky; a
larger-aperture array telescope, with an \'etendue close to the Rubin
Observatory, could reach g=24.3 in five nights. These arrays can build
two-color, million-epoch movies of the sky, enabling sensitive and rapid
searches for high-speed transients, fast-radio-burst counterparts,
gravitational-wave counterparts, exoplanet microlensing events, occultations by
distant solar system bodies, and myriad other phenomena. An array of O(1,000)
telescopes, however, would be one of the most complex astronomical instruments
yet built. Standard arrays with hundreds of tracking mounts entail thousands of
moving parts and exposed optics, and maintenance costs would rapidly outpace
the mass-produced-hardware cost savings compared to a monolithic large
telescope. We discuss how to greatly reduce operations costs by placing all
optics in a thermally controlled, sealed dome with a single moving part.
Coupled with careful software scope control and use of existing pipelines, we
show that the Argus Array could become the deepest and fastest Northern sky
survey, with total costs below $20M.
