• 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...


NIR Spectrograph architecture concept design (R5000) - (Camera is F/1.71)

NIR Spectrograph architecture concept design (R15000) - (Camera is F/1.71) 


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

 VIS Spectrograph architecture concept design

Who are we? Infos on the MOSAIC consortium.


Scientific goals and milestones: why MOSAIC?


How do we get there? All the technology behind MOSAIC.


What performance can we expect from MOSAIC?


How will MOSAIC fit in the instrumental landscape?