Tierras reutilizes the 1.3-m telescope originally commissioned in 1997 to serve as the Northern-hemisphere component of the Two Micron All Sky Survey (2MASS). The facility is designed to achieve a photometric precision of 250 ppm on a time scale of both 10 minutes and across an observing season. The five design choices that enable this precision include:

A four-element focal reduced and field-flattener to increase the field-of-view of the telescope from 0.19 deg to 0.5 deg on a side, accommodating a greater number of calibration sources.

A custom narrow (40 nm) bandpass filter centered around 863.5 nm to minimize precipitable water vapor errors known to limit ground-based photometry of M dwarfs.

A 4K x 4K Teledyne e2v bulk silicon deep-depletion CCD with a quantum efficiency of 85% in the Tierras bandpass, operating in frame transfer mode.
A fully robotic facility that automatically performs observations of target stars on every clear night.
For more details on the design, construction, and commissioning of the Tierras Observatory, please refer to García-Mejía et al., 2020.
See our team’s posters from Exoplanets V for an overview of the facility’s current on-sky performance.