The 67/92-cm Schmidt telescope, built in 1966, is located at Mount Ekar, close to the Copernico 1.82m telescope. It was moved from the original position at the Observatory site near Asiago in July 1991 to take advantage of the higher altitude and lower light pollution of the new observational site.
The building is not a traditional dome: the rotating part is of octagonal shape for easier mechanical assembling and was designed in part to test the proposed solution for the Telescopio Nazionale Galileo (TNG) located in La Palma (Canary Island). The main optical characteristics of the telescope are:
Correcting plate: 67 cm diameter in UBK7 Schott glass
Spherical mirror: 91 cm diameter in Duran-50 Schott glass
Focal length: 215 cm (f/3.2, scale 95.9 arcsec/mm).
Until 1998 the telescope was used with a photographic plate of 20x20 cm, corresponding to a field-of-view of 5.1x5.1 deg. Originally, the telescope was equipped with a 67 cm, 4.5 deg angle UV-transparent objective prism, with a reciprocal dispersion at H gamma of 650 Å/mm, and a 67 cm, 1 UV-transparent objective prism, with a reciprocal dispersion at H gamma of 1010 Å/mm. The two prisms were used in direct or reversed combination. Objective prisms are no longer available. From 2000 to 2002 a thick, front-illuminated 2048x2048 LORAL CCD was mounted (details can be found in technical report n.19).
In 2009 a SBIG CCD has been donated by the Rotary Club, district 2060 and the Schmidt 67/92 was refurbished, mainly for outreach activities.
In 2017 the telescope has been considerably renovated and remotely controlled, thanks to a renewed scientific interest. A new Moravian CCD camera (detector: KAF-16803 4096×4096 active pixels, 9 μm each) and a new guider camera were purchased, along with a new set of uBVgri filters. See technical report n.27.
In 2020/2021 new updates of both hardware and software allowed the implementation of the fully robotic operational mode (see RoboSchmidt User Manual google doc): the Schmidt 67/92 telescope operates without the presence of astronomers or technicians during night time. The observing blocks (OB) are submitted at any time by the PIs of the accepted proposals. The Robotic System has a rapid-response capability that allows it to interrupt regular observations in order to observe transient phenomena with high priority.
Coordinates of the Schmidt 67/92 central pillar:
CCD TECHNICAL DATA
ON-Semi KAF-16803 (active area: 4096×4096 pixels, prescan: 30 pixels)
CCD scale: 0.87 arcsec/px (unbinned);
Pixel size: 9 μm
FOV: 59 x 59 arcmin
Full well capacity: 100 ke-
Dark current: 0.01 e-/pixel/sec at -30°C
A/D Converter: 16 bits
A/D Gain: 1.6 e-/ADU
Readout noise: 10 e-
Full frame readout time: 22 sec
Multistage Peltier cooler (max ΔT -60°C from the CCD heatsink temperature
Filters wheel with B and V Johnson-Bessel, u g r i Sloan filters; it is possible to work without filter as well
Minimum exposure time with electromechanical shutter: 0.2 sec
AUTOGUIDER TECHNICAL DATA
Sony IMX-174M (active area: 1920 × 1200 pixels)
CCD scale: 0.56 arcsec/pixel (unbinned)
Pixel size: 5.87 μm
FOV: 18 x 11.2 arcmin
The camera is mounted on a linear positioner that permits to adjust the focus independently from the main CCD camera focus
Minimum exposure time: 50 μsec