Instrument Design

WFC3 Instrument Handbook

For more detailed descriptions of WFC3's components and behaviors, see the WFC3 Instrument Handbook

Two Channels

Observations with WFC3 can make use of the UVIS or IR Channels, and a channel select mechanism directs incoming light to the desired channel. The light path within WFC3 for both channels is shown in the figure below. The IR light path is drawn in red, and the UVIS light path is drawn in pink.

The WFC3 detectors are capable of observing at all wavelengths between 200 - 1700nm. The QE curves for the UVIS and IR detectors are shown below. These curves do not include the effects of HST's OTA, nor WFC3's optics and filters.

Detector Characteristics

IR Channel

Components: Teledyne 1Kx1K HgCdTe detector. MBE-grown, substrate removed.

Total Field of View: 123 x 136 arcsec

Pixel Size: 0.13 arcsec

Nominal Operating Temperature: 145 K

Dark Current: 0.048 e-/sec/pix (median) [See WFC3 IHB, Table 5.1]

Dark Current Tail (% of pixels with Dark Current >0.4 e-/sec/pix): 0.7%

Readnoise: 21 e- (CDS), 12 e- (16-read linear fit) [See WFC3 IHB, Table 5.1]

Full Well: 77,900 e- [See WFC3 IHB, Table 5.1]

UVIS Channel

Components: 2 e2V thinned, backside illuminated, UV optimized 2Kx4K CCDs

Total Field of View: 162 x 162 arcsec

Pixel Size: 0.04 arcsec

Nominal Operating Temperature: -83C

Dark Current: 3 e-/hr/pix (median) [See WFC3 IHB, Table 5.1]

Readnoise: 3.1 e-

Full Well: 63,000 -- 72,000 e- [See WFC3 IHB, Table 5.1]

Filters

WFC3's complement of filters cover the entire useful wavelength range dictated by the detectors. Individual plots of filter throughputs are available in the WFC3 Handbook. More information about WFC3 filters can be found on the WFC3 filter page.

The plots below show the total system throughput for all of WFC3's filters.

WFC3 contains a large compliment of filters: 63 in the UVIS channel, and 17 in the IR channel. Actual transmission data for all filters can be found on the WFC3 CDBS ftp site. See the SYNPHOT site for information on how to use these data.

View the full throughput list.