Technical design

IBIS 2.0 is essentially formed by a series of two Fabry-Perot (FP) interferometers and a set of narrow-band (NB) interference filters placed between them, used in a classic mount and in axial-mode (Cavallini, 2006). It, however, consists of several channels and more than forty components, some of which with movement functions. All the components are all settled on air on optical rails that are anchored to a large optical bench. The FPs and the NB filters are carefully thermalized with a temperature control better than 0.1 degree.

Figure 1 shows the instrument mounted on an optical bench in the "Dario Lorenzetti" Optical Laboratory of the INAF Osservatorio Astronomico di Roma. 

Figure 1: IBIS 2.0 with new optical configuration mounted on the optical bench of the laboratory at INAF - Osservatorio Astronomico di Roma.

The project underwent several phases due to the evolution and availability of the solar telescopes at the Teide Observatory. In particular, the opto-mechanical layout of the instrument was first investigated for installation with a horizontal setup on an optical table at the German Vacuum Tower Telescope (VTT), but alternative setups were considered as well.

Indeed, the optical scheme of the instrument used at DST needs revisions for the installation at the new telescope. These revisions account for the new operating conditions and for simplifications of some instrumental channels, specifically the calibration channels.

Figure 2 shows the optical design conceived for the installation of IBIS 2.0 at the VTT. 

Figure 2:  Optical layout proposed for IBIS 2.0 at VTT.

A new control system, based primarly on Beckhoff PLCs, will allow automatic control procedures of IBIS, reducing the time required for calibration.

Figure 3 displays the movement functions driven by the new control electronics of the project for the new optical design proposed.

Figure 3: Moving parts foreseen for IBIS 2.0