Brazilian Tunable Filter Imager (BTFI) Preliminary Design Review (PDR)‏ USP-IAG Universidade de São Paulo 18-19th June 2008 BTFI Optics (Keith Taylor) Version 1.0

Optics Requirements Focal Reducer: – Input f/16.5 (SOAR & SAM) with f/7.1 camera 0.11”per 16µm pixel FoV = 3’ on-a-side (format = ) – IQ requirements: SAM (Focal RC = -800mm): 80% in ~2-pixels SOAR (Focal RC = +1000mm): 80% in ~3-pixels – Collimated Space: Pupil  = 50mm Length ~ 450mm (to accommodate iBTF)

A A = Input Focal Plane B B = Field Lens C C = Fold mirrors E E = Collimator F 1 = iBTF (VPHG 1 ) F1F1 F2F2 F 2 = iBTF (VPHG 2 ) G0G0 G1G1 G 0 = 0 th order pupil G 1 = 1 st order pupil H H = 0 th order fold mirror I1I1 I0I0 I 0 = 0 th order Camera I 1 = 1 st order Camera J 0 = 0 th order camera fold J1J1 J0J0 J 1 = 1 st order camera fold K1K1 K2K2 K 0 = 0 th order detector K 1 = 1 st order detector Optics Layout

A A = Input Focal Plane B B = Field Lens C C = Fold mirrors E E = Collimator F 1 = iBTF (VPHG 1 ) F1F1 F2F2 F 2 = iBTF (VPHG 2 ) G0G0 G1G1 G 0 = 0 th order pupil G 1 = 1 st order pupil H H = 0 th order fold mirror I1I1 I0I0 I 0 = 0 th order Camera I 1 = 1 st order Camera J 0 = 0 th order camera fold J1J1 J0J0 J 1 = 1 st order camera fold K1K1 K2K2 K 0 = 0 th order detector K 1 = 1 st order detector Optics Layout

A B C E F1F1 F2F2 F 1 – iBTF (VPHG 1 ) simple rotation F 2 – iBTF (VPHG 2 ) rotation + translation FP P = High Resolution FP I = Low Resolution FP I FP P IF I IF P IF I = Interference Filter - Image Plane IF P = Interference Filter - Pupil Plane K1K1 K0K0 Optics Layout

BTFI performance on SAM (GLAO) and at Nasmyth (SL) Boxes: 2-by-2 pixels Wavelengths: 370, 480 & 1,000nm Optical Design by: Damien Jones Prime Optics, Qld., Australia

BTFI performance on SAM (GLAO) and at Nasmyth (SL) Boxes: 4-by-4 pixels Wavelengths: 370, 480 & 1,000nm IQ (FWHM) performance: GLAO < 70 mas SL <180 mas Optical Design by: Damien Jones Prime Optics, Qld., Australia

Ghost Analysis On-axis ghosts (  <1mm) between: – Etalon (dummy) and detector – Field lens and detector – Both negligible (<10 -6 ) with good A/R coatings Pupil ghosts (< ): – Worst avoided by good A/R coating – Others quenched by: Pupil aberrations Vignetting