Wide Field Camera 3 (WFC3) Credit: NASA/STScI

The Wide Field Camera 3 (WFC3) is a fourth-generation instrument that is designed to be installed in the Hubble Space Telescope during Servicing Mission 4 (SM4). It will replace the WFPC2 instrument, but some components of the original WFPC1 are maintained and reused.

A key feature of WFC3 is its panchromatic wavelength coverage. By combining two optical/ultraviolet CCDs with a near-infrared HgCdTe array, WFC3 will be capable of direct, high-resolution imaging over the entire wavelength range from 200 to 1700 nm. Equipped with a comprehensive range of wide-, intermediate-, and narrow-band filters, WFC3 will have broad applicability to a variety of new astrophysical investigations.

The optical design of WFC3 features two independent channels, one sensitive at ultraviolet (UV) and optical wavelengths, approximately 200 to 1000 nm (the UVIS channel), and the other sensitive at near-infrared (near-IR) wavelengths, approximately 900 to 1700 nm (the IR channel).

A channel-selection mirror will direct on-axis light from the HST Optical Telescope Assembly (OTA) to the IR channel, or can be removed from the beam to allow light to enter the UVIS channel. This means that simultaneous observations with the UVIS and IR detectors are not possible.

	COS - Cosmic Origins Spectrograph
	FGS - Fine Guidance Sensors