Copernico 1.82m

The Copernico 1.82m telescope and its instruments are operated by INAF Astronomical Observatory of Padova, atop of Mount Ekar (Asiago). It is the largest optical telescope in Italy. Dedicated to Nicolas Copernicus, it has been in operation since 1973 for optical imaging, low to medium-high resolution spectroscopy, polarimetry using two main instruments: AFOSC (Asiago Faint Objects Spectrograph and Camera) and Echelle spectrograph.


Longitude: 11° 34' 08.397" E - Latitude: 45° 50' 54.894" N - Altitude: 1376.2m



Optical design of the telescope is a Classic Cassegrain with equivalent focal number f/9.

The primary mirror M1 (made of Schott Duran 50) has a diameter of 182cm.

An active system for the movements of the secondary mirror is implemented. This unit, in addition to the standard focusing, allows one to control both X and Y positions of M2 and tilt angle ALPHA, BETA. The whole system is controlled by a dedicated PC. The mirror is periodically re-coated with aluminium using the vacuum chamber at Mount Ekar.

The main characteristics of the mirrors:


The limit of pointing for the declination axis is dependent on the altitude of the target. The minimum altitude is fixed at 20 degrees by both software and hardware limit switch. It is strongly advised that this position never be reached.The pointing accuracy is better than 1 arcmin all sky. The coordinates are read by two absolute encoders with a resolution of approximately 4 arcsec.

The Cassegrain Focus

The Cassegrain Focus (f/9, scale 12.6 arcsec/mm at about 20 cm from the rear main flange) is the main focus of the telescope. Focusing is performed by moving the secondary mirror along the Z axis; this movement is controlled by a dedicated PC.

The Nasmyth Focus

A 45 degree tertiary mirror can be inserted to deviate the beam to the Nasmyth focus in the East side of the fork.


The dome of the telescope is on the third floor of the telescope building and has a diameter of 15 m.

The building is equipped with an external elevator to enable maintenance of the dome. Aperture and rotation of the dome are controlled by the TPS (Telescope Pointing System) software.

In addition to the observing floor the building contains offices, mechanical and electronic laboratories and a small kitchen.


Pointing of the telescope and auto-guiding is performed using TPS software. During observations the dome is automatically rotated such that the dome window is always aligned with the telescope pointing.

See the Telescope Manual for details (PDF)

photo by Lino Contri


At the Copernico 1.82m telescope two instruments are available: a low-medium resolution spectrograph and imager (AFOSC) and an high resolution spectrograph (Echelle).

The two instruments are complementary for spectral resolution and are therefore mounted in turn at the telescope following the moon cycle (AFOSC being usually available during grey and dark time).


Since 1983 several CCD detectors have been installed at instruments' focal planes. Currently only two detectors are used with the scheduled instruments. Their characteristics and performances are reported at following link: