The Wide Field Camera 3 (WFC3
) was installed in May 2009 during Servicing Mission 4, replacing the highly accomplished WFPC2. This camera provides ultraviolet, optical, and near-infrared imaging through two independent channels. These channels cannot be operated simultaneously, although they can be operated sequentially within the same orbit. Their location in the HST
field of view can be seen in Figure 2.2
The wide field ultraviolet-visible channel (WFC3/UVIS
) is a high throughput, panchromatic camera with a field of view of 162" x 162", sensitive to wavelengths from 200 nm to 1000 nm. The total system throughput with this camera is 28% at 600
nm (see Figure 4.2
). The detector is a pair of butted, 2K by 4K, thinned and backside-illuminated CCDs with an ultraviolet-optimized anti-reflective coating and 15
x 15 μ
m pixels. The plate scale is 0.04 arcsec/pixel. In addition to wavelength optimization, the primary differences between the WFC3 and ACS CCDs include a lower read noise (3 e-
for WFC3, 5 e-
for ACS) and a smaller interchip gap (465 μ
m rather than 750 μ
m). The UVIS channel provides 62 broad-, medium-, and narrow-band filters, and one grism.
The wide field high-throughput infrared channel (WFC3/IR
) has a field of view of 136" x 123" over the wavelength range of 800 nm to 1700 nm. The total system throughput with this camera is 50% at 1600 nm (see Figure 4.2
). The detector is a 1K by 1K HgCdTe Teledyne array with 18 x 18 μ
m pixels. The plate scale is 0.13 arcsec/pixel. The detector has 12 e-
RMS read noise in a 16-sample non-destructive readout sequence, or 21 e-
RMS read noise in the difference of two samples (a correlated double sample). The IR channel provides 15 broad-, medium-, and narrow-band filters and two grisms.
See the WFC3 Instrument Handbook
and WFC3 ISR 2012-08
for further discussion of spatial scanning.