[1][2] It is situated at 1,029 metres (3,376 ft) ASL atop Mount John at the northern end of the Mackenzie Basin in the South Island, and was established in 1965.

The nearest population centre is the resort town of Lake Tekapo (pop. >500).

Approximately 20% of nights at UCMJO are photometric, with a larger number available for spectroscopic work and direct imaging photometry.

Opened in December 2004, this telescope was built by Japanese astronomers and is dedicated to the Microlensing Observations in Astrophysics (MOA) project.

Photometric imaging is by CCD camera and spectroscopy is by fibre-optic cable to the HERCULES spectrograph.

[citation needed] In June 2008 it was reported at the meeting of American Astronomical Society that using their new MOA-II telescope, the observatory discovered what was at the time the smallest planet known outside of our Solar System.