Le Stelle Vanno a Scuola (SVAS)
Instruments
Telescope Celestron C14
The Celestron C14 is a catadioptric optical system in configuration Schmidt-Cassegrain, it has 356mm of diameter and 3910mm of focal lenght. In its standard configuration it has a focal ratio f/11.
It is built with two spherical mirrors. Primary mirror, located in the rear part of the tube, collects the light and reflects it to the secondary mirror, located in front of the telescope. There the light is reflected for the second time and, crossing a hole in the primary mirror, reaches the focus. In front of the optical tube there is a correcting lens designed to avoid spherical aberration.
A CCD camera Apogee Alta U8300 and a filter wheel are connected to the telescope, in order to acquire high resolution images, in different wavelenghts, of the observed objects.
Solar telescope Coronado HELIOS 1
The Coronado HELIOS 1, fixed in parallel to the main telescope, is a solar telescope by "Coronado Instruments Ltd". It is an achromatic refractor of 70mm diameter and 400mm focal lenght.
The telescope is equipped with a frontal energy rejection filter (ERF) that prevents ultraviolet and infrared radiation from entering the the instrument and allows to check the image luminosity. Inside the optical tube a narrow band filter provide a pass band of 0.8 angstrom centered on the 656.28 nm wavelenght (Hα line of the Balmer series of hydrogen). Thanks to the Hα filter it is possible to see both prominences and the other features of solar chromosphere, like facules and filaments.
A CCD camera Starlight XPress able to acquire color images of the entire solar disk is connected o the telescope.
Mount Paramount ME
The optical instruments are installed on a german equatorial mount, that allows the automatic pointing of the telescope and to compensate the apparent motion of the celestial sphere. It is the "Paramount ME" mount, a totally robotic mount that, through an apposite control system, allows the remote management of the telescope with the software TheSkyX.
CCD camera Apogee Alta U8300
The CCD camera mounted at the focus of Celestron C14 telescope is an Apogee Alta U8300 by "Apogee Instruments Inc". It is a digital sensor able to acquire 16 bit (65536 levels) grey scale images. The pixel matrix that makes up the sensor is a rectangle of 3326 x 2504 pixel, each one having linear dimensions of 5.4µm x 5.4µm. The entire sensor has dimensions of about 18mm x 13.5mm. The CCD camera is equipped with a cooler that utilizes a system of Peltier's cells to bring the sensor to temperatures between -20°C and -40°C.
Heat exchanges are governed by radiators and two small fans visible in the rear part fo the CCD camera. The sensor, with integrated shutter, is totally controlled by an apposite control system that manages cooling and exposure times.
CCD camera Starlight XPress SXV-M8C
The CCD camera mounted at the focus of the solar telescope Coronado is a SXV-M8C by "Starlight XPress". It is a digital sensor able to acquire 16 bit color images.
The pixel matrix that makes up the sensor is a rectangle of 2312 x 1720 pixel, each one having linear dimensions of 3µm x 3µm. The entire sensor has dimensions of about 7.2mm x 5.4mm. The CCD camera is equipped with a cooler system that brings the sensor to 30° C below the dome temperature.
Filter wheel
Acquiring astronomical images with filters is very important in order to obtain information on the physical and chemical proprieties of the observed objects. Moreover, the technique to combine three images taken with red, green and blue filters allows to have color images using a monochromatic CCD.
The C14 telescope is equipped with a filter wheel that host several different filters. The filters that can be selected directly from the camera control system.
Two series of filters are available: RGB to take color images and UBVRI for photometry.