  We report on the status of the Tierras Observatory, a refurbished 1.3-m
ultra-precise fully-automated photometer located at the F. L. Whipple
Observatory atop Mt. Hopkins, Arizona. Tierras is designed to limit systematic
errors, notably precipitable water vapor (PWV), to 250 ppm, enabling the
characterization of terrestrial planet transits orbiting $< 0.3 \, R_{\odot}$
stars, as well as the potential discovery of exo-moons and exo-rings. The
design choices that will enable our science goals include: a four-lens focal
reducer and field-flattener to increase the field-of-view of the telescope from
a $11.94'$ to a $0.48^{\circ}$ side; a custom narrow bandpass ($40.2$ nm FWHM)
filter centered around $863.5$ nm to minimize PWV errors known to limit
ground-based photometry of red dwarfs; and a deep-depletion $4K \times 4K$ CCD
with a 300ke-full well and QE$>85\%$ in our bandpass, operating in frame
transfer mode. We are also pursuing the design of a set of baffles to minimize
the significant amount of scattered light reaching the image plane. Tierras
will begin science operations in early 2021.
