• Total system bandwidth is 0.37 to 1.8μm
• Cross over between Vis optimised system and NIR optimised system is 0.8μm
• Coverage at R5000 is achieved with 3 VPH in Vis and 3 VPH in NIR

• Initial optical concept for the visible spectrograph, with the final optical architecture, indicates that the beam size will be around 200-230 mm
• Camera speed is ~ F/1.6
• ie a feasible design
• [The concept is actually quite close in terms of parameters to the WEAVE spectrograph that Oxford, GEPI and NOVA are involved in]
• More detailed concept is currently under investigation...

Visual Spectrograph

Top view of the optical model on the optical bench with science light beam. Common optics: Slit lens, Collimator Mirror, Set of Corrector lenses, Volume Phase Holographic Grating (VPHG, Low Res and High Res, Camera, Detector. Camera position is low-resolution with small angel and the high resolution at steep angle and sketched mechanical structure.

Characteristics: Collimator F/3.64 pupil 190 mm, Camera F/1.7, total size 2 x 2.5 meter, height 1 meter