SMARTS Consortium: 1.5-meter Telescope

The Small and Moderate Aperture Research Telescope System (SMARTS) Consortium operates four small telescopes on Cerro Tololo in Chile. Membership in SMARTS is open to individuals or institutions, including international partners.

The SMARTS 1.5-meter telescope is an open-tube Cassegrain that has been operated with both imagers and spectrographs. As of August 2020, it is operated with a single instrument, the high-resolution optical spectrograph CHIRON.

SMARTS 1.5-meter Telescope

Name(s) SMARTS 1.5-meter Telescope
Status Operational 
Broad Science Goals  
Site Cerro Tololo Inter-American Observatory, Chile 
Location Coordinates 30º10′09.43’ S
70º48.24.44’ W
Optical Design Cassegrain Reflector telescope
Field of View  
Diameter: Primary M1 1.5 meters
Material: Primary M1  
Diameter: Secondary M2  
Material: Secondary M2  
Mount Equatorial mount
First Light Date 1968
Adaptive Optics  

About the SMARTS 1.5-meter Telescope

The 1.5-m telescope is mounted on an asymmetric, off-axis mount and is used on the east side of the pier. It is not possible to reverse the telescope over the pier.


The CHIRON high-resolution spectrograph is the only instrument in use at the SMARTS 1.5-m telescope as of August 2020. In the past, the 1.5-m has also hosted the following (now retired) instruments: Bench Mounted Echelle (BME) Spectrograph, the 1.5-m RC Spectrograph, the Automated Single Channel Photometer (ASCAP), OSIRIS and CIRIM IR imagers, a Cass focus CCD (CFCCD) Imager and the CPAPIR wide-field IR Imager.

All Cassegrain instruments are mounted on an instrument rotator, and thus they may be placed at any position angle on the sky. However, rotation is performed manually and can only be done near zenith, so changing the PA usually requires at least 10 min. The angle can be read to ± 0.1 degree. Variable speed, D.C. motors have been incorporated into both the right ascension and declination drives in order to improve the efficiency of the telescope for infrared work.

Restricted View Towards the 4.0-m

The view of the 1.5-meter telescope is restricted when looking towards the SE by the dome of the 4.0-meter telescope. At the following declinations, exceeding the indicated hour angle will cause the view to be obstructed:

Hour Angle
(h m)
-50 5:44 E
-55 5:30 E
-60 5:05 E
-65 4:55 E
-70 4:50 E
-75 4:10 E

Graph of theoretical image quality over the FOV and sensitivity of focus with temperature change.