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Hubble Space Telescope Primer for Cycle 22 > Chapter 4: Cycle 22 Scientific Instruments > 4.1 Advanced Camera for Surveys (ACS)

4.1 Advanced Camera for Surveys (ACS)
The Advanced Camera for Surveys (ACS) was installed during Servicing Mission 3B in March 2002. Failures in the ACS CCD Electronics Box and Low Voltage Power Supply in January 2007 made the WFC and HRC channels inoperable (the SBC continued to function). The problem was partially fixed during Servicing Mission 4 in May 2009, restoring use of the WFC but not the HRC.
In its current state, the camera provides ultraviolet and wide field optical imaging through two channels that have adjacent but not contiguous fields of view. The locations of these channels in the HST focal plane are presented in Figure 2.2.
The Wide Field Channel (ACS/WFC) provides high throughput and wide field imaging. The camera has a 202" x 202" field of view from 350 nm to 1100 nm. Total system throughput is 42% at 600 nm (see Figure 4.2). The WFC detector is a pair of butted (2K by 4K), thinned and backside-illuminated, SITe CCDs with a red-optimized coating, a long wavelength halo fix, and 15 x 15 μm pixels. The plate scale is 0.050 arcsec/pixel. The WFC PSF is critically sampled at 1160 nm and undersampled by a factor of three at 370 nm. Well-dithered observations with the WFC should result in a reconstructed PSF FWHM of 0.1" to 0.14".
The Solar Blind Channel (ACS/SBC) is optimized for high resolution, solar-blind far-UV imaging. The camera has a 34" x 31" field of view from 115 nm to 170 nm and a peak efficiency of 6% (see Figure 4.2). The detector is a solar-blind CsI Multi-Anode Microchannel detector Array (MAMA) with 25 x 25 μm pixels. The plate scale is 0.032 arcsec/pixel.
The ACS High Resolution Channel (ACS/HRC) provided high resolution imaging from Cycle 11 through Cycle 14. This camera is not available for Cycle 22. More information about the HRC can be found in Appendix C:Legacy Instruments: Legacy Instruments.
In addition to these prime capabilities, ACS also provides imaging polarimetry (Section 4.7.1) and slitless spectroscopy (Section 4.7.2). Further information can be found in the ACS Instrument Handbook.

Hubble Space Telescope Primer for Cycle 22 > Chapter 4: Cycle 22 Scientific Instruments > 4.1 Advanced Camera for Surveys (ACS)

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