[1] It was later moved to Palacio del Ex-Arzobispado in Tacubaya, then on the outskirts of the city on the west side of the Federal District.

In 1967 excessive air pollution and night light pollution caused another move, from Puebla to atop the Sierra San Pedro Mártir mountain range of Baja California state in Northwestern Mexico.

[4] The San Pedro Mártir OAN site has been found to have excellent astronomical seeing.

Mirror fabrication for the SPMT began in 2009, with a 6.5 m aperture optimized for wide angle infrared survey work.

The primary instrument would be a 124 x 2k x 2k pixel infrared detector array with a 1 degree FOV prosecuting the Synoptic All-Sky Infrared Survey (SASIR), a four-year, deep all-sky survey.