DL – IFU (Prieto/Taylor) Slicer: –25mas sampling … 0.9mm slices ~f/250 (assuming no anamorphism) Detector = 2k array of 18um pixels –Slit subtends 1-pixel (spectral dithering as for TiPi) Camera f-ratio = f/5 (double TMA a la JWST system) Full window requires ~800 pixels –4 slits per spectrograph/detector –Slit height = ~1000 pixels or 30-by-30 slicer with FoV ~ arcsec. –4 slits gives FoV ~1.5 2 arcsec. Is this a sufficient field ? Or do we need 2 or 4 units ? –NB: SRD asks for ~4 2 arcsec –If only we could use a 4 2 k, 9  m pixel, array at f/2.5 ! Assume fore-optics can switch in factor of 5 magnification to give: –25mas ; 20mas; 15mas; 10mas; 5mas –5mas option would feed spectrograph at f/12.5 –What beam-size would be required ? 50mm OK ?

Optical Components Cool box: –45 deg. fold to vertical –Pupil imager onto ~25mm DM Field lens or Field mirror ? (not exactly at focus) –DM as steering mirror feeding mirror at field stop (as in TiPi) but also an imaging system (as in TiPi) to give ~10 arcsec D-L field DM can switch from IFU to direct imaging field by small tip/tilt –Object can be viewed directly and then selected into IFU field –Surrounding objects can be imaged directly while doing IFU spectroscopy

Optical Components Cryo box: –Magnification optics and scale changer optics Non-anamorphic (25mas ; 12.5mas ; 5mas) Cold stop (rotating ?) –2 contiguous 60-slice slicer units square FoV 2 slits into 1 spectrograph –Double TMA spectrograph (a la JWST/NIRSPEC) Collimator somewhere between f/10 and f/20 (tbd) Camera f/5 Beam size ~50mm (plus pupil diffraction)

Scope of Work Optical concept at same level as TiPi –Field lens/mirror –DM – steering & image/IFU selector –Imaging system (FoV ~10” D-L) –Fore-optics / scale changer –Slicer unit –Spectrograph Approx. wave-front error budget ? Challenges: –Larger FoV ~3 arcsec 2 ? –Faster cameras ~f/2.5 ?