| Configuration 1: plate scale 10 mas/pixel, field of view ~3"
| Configuration 2: plate scale 20 mas/pixel, field of view ~6"
| Configuration 3: plate scale 100 mas/pixel, field of view ~30"
The camera optical layout features three Calcium Fluoride lenses, to maximize the infrared transmission; the three optical configurations are obtained by moving two lenses along the optical axis, by mean of remotely controlled mechanisms. Two commercial filters are included in the design with band-passes 1050-1100 nm and 1500-1700nm (including the detector response cut-off at 1700nm). The two filters are mounted on a positioning system, which also includes a blank position. In order to minimize the stray light and the spurious background (non-thermal), baffles and pupil stops (one stop for each configuration) are included inside the camera.
In order to meet all the required functionalities, a total of four motorized functions are included in the camera design and an anti-collision system is implemented. All motorized stages are off-the-shelf, while the mechanical structure of the camera, including optics mounts and interfaces to the telescope, are a custom design. The infrared camera is a commercial camera manufactured by Xenics, employing an InGaAs
detector (320x256 pixels, 30 micron pitch) and equipped with a Peltier cooler and a liquid cooling system. All the other heat dissipating surfaces are chilled by a liquid cooling system, not to introduce any air turbulence especially in the critical regions inside the IRTC and in front of the AO wavefront sensor. Dedicated custom software has been developed for motion control, optical configuration set-up, including filter exchange and pupil stops positioning, set-up of the infrared camera and image acquisition.
- 24 Mar 2013