  Observing the ultraviolet (UV) sky for time-variable phenomena is one of the
many exciting science goals that can be achieved by a relatively small aperture
telescope in space. The Near Ultraviolet Transient Surveyor (NUTS) is a
wide-field ($3^\circ$) imager with a photon-counting detector in the near-UV
(NUV, 200-300 nm), to be flown on an upcoming small satellite mission. It has a
Ritchey-Chretien (RC) telescope design with correction optics to enable
wide-field observations while minimizing optical aberrations. We have used an
intensified CMOS detector with a solar blind photocathode, to be operated in
photon-counting mode. The main science goal of the instrument is the
observation of transient sources in the UV, including flare stars, supernovae,
and active galactic nuclei. NUTS's aperture size and effective area enable
observation of relatively unexplored, brighter parts of the UV sky which are
usually not accessible to larger missions. We have designed, fabricated, and
assembled the instrument, and the final calibrations and environmental tests
are being carried out. In this paper, we provide the scientific motivation and
technical overview of the instrument and describe the assembly and calibration
steps.
