The Thirty Millimeter Telescope
  A near-infrared telescope with an effective aperture diameter of thirty
millimeters has been developed. The primary objective of the development is to
observe northern bright stars in the $J$, $H$, and $K_{\rm s}$ bands and
provide accurate photometric data on those stars. The second objective is to
repeatedly observe a belt-like region along the northern Galactic plane ($|b|
\le 5^\circ$ and $\delta \ge -30^\circ$) to monitor bright variable stars
there. The telescope has been in use since December 2016. The purpose of this
paper is to describe the design and operational performances of the telescope,
photometric calibration methods, and our scientific goals. We show that the
telescope has the ability to provide photometry with an uncertainty of less
than 5\% for stars brighter than 7, 6.5, and 6~mag in the $J$, $H$, and $K_{\rm
s}$ bands, respectively. The repeatability of the photometric measurements for
the same star is better than 1\% for bright stars. Our observations will
provide accurate photometry on bright stars that are lacking in the Two Micron
Sky Survey and the Two Micron All-Sky Survey. Repeated observations at a good
cadence will also reveal their nature of the variability in the near-infrared.
