Moment

Québec. The thinned, back-illuminated, 10,580 × 10,560 pixelsensor has pixel pitch of 9.0 × 9.0 microns and a peak quantumefficiency of 94% in the r´. The entire 112-megapixel array canbe downloaded in 2 seconds. This is accomplished by the useof 16 read ports. Cooled to -100 °C, the camera has effectivelyno dark noise (1e-/pix/hr). 16-bit quantization is used with an80,000e- well size. The use of a monolithic sensor will improveoverall efficiency of the camera by eliminating the gaps foundin more traditional large-format mosaic cameras (no ditheringrequired), and will simplify the calibration, image processing,and geometric corrections.Figure 8 — OMI spot curve with 80% encircled energy, based on9-µm pixel pitch and 0.76”/pixel5. Active OpticsIntegrated into the prime-focus assembly is a hexapod with6 degrees of freedom. This allows motion in lateral, rotation,z-axis, and tip/tilt with +/-1 µm repeatability. The hexapodhas the ability to respond quickly (20Hz) and may be used inthe future as a form rapid x, y lateral tracking. The hexapodallows a collimation map to be applied on a continuous basisas the telescope changes position, thereby compensating forgravitational distortions and assuring sharp edge-to-edgeimages across the sky. In addition, the hexapod will be used forprecision focus.6. The Camera and GuiderThe Camera will be made by Spectral Instruments and employsthe largest chip ever made, a 4˝ × 4˝ CCD image sensor with 112million pixels. The sensor is fabricated by Waterloo’s DALSA,is manufactured at Canada’s only chip factory, in Bromont,Figure 10 — QE for STA-1600A with thinned-backside illuminationwith a 2-layer HfO 2-MgF 2anti-reflective coatingMag. r´ #/deg 2 #/Sen. Totalstarss/n s/n s/nExposure ➔ 1s 0.5s 0.1s10.25 7 0.12 0 388 267 10010.75 11 0.19 0 303 206 7211.25 16 0.28 1 235 156 5011.75 23 0.40 1 180 116 3412.25 33 0.58 2 135 85 2312.75 46 0.82 3 100 60 1513.25 68 1.19 4 72 41 1313.75 96 1.66 6 50 28 614.25 130 2.27 9 34 18 4Table 4. Guide-star probability at 90° galactic latitude. Thes/n is based on a seeing of 1.25” FWHM (r’). Star count isbased on Bahcall and Soneira (1980).Figure 9 — STA-1600A 112-megapixel CCDFour Dalsa FT-50, 1024 ×1024 pixels, 5.6-µm pitch progressivescanframe-transfer CCDs will be used for guiding. These willApril / avril 2009JRASCCelebrating the International Year of Astronomy (IYA2009)57