Optical Layout
The Zemax model of the SHARK-VIS optical layout is shown in the picture on the right. The access to the f#15 telescope focal plane, the pupil plane and a final f#25 detector focal plane is achieved by deploying an optical relay based on off-axis parabolas. A triplet ADC, positioned upstream to the f#15 focal plane, removes the atmospheric dispersion for observations in wide band filters, which are used for some of the science cases.
Downstream to the ADC, a "Guide wheel" may insert a number of cube beam splitters to divert part of the beam to the guide camera and/or inject light coming from a calibration source into the science light path. In the following picture we see a rendering of the instrument "core" where the science light path (green) splits into guide path (purple) and crosses the calibration light path (yellow).
This optical design resulted robust and almost diffraction limited in the visible. The next picture shows the spot diagram of a Monte Carlo simulation for one of the worst possible alignment axes; with refocusing only, a final lambda/50 wavefront error is obtained.
A scheme of the instrument with the various components and the light path is shown below, considering a scientific observation in the Hα filter.
