The following pages contain information on the performance of Wide Field Camera 3 and its components.

Flight Detectors


  • Components: 2x2Kx4K thinned, backside illuminated, UV optimized e2v CCDs
  • Wavelength Range: 200 to 1000 nm
  • Total Field of View: 162 x 162 arcsec (rhomboidal)
  • Pixel format: 2 butted 2051x4096, 31-pixel gap (1.2").
  • Pixel Size: 15x15 microns
  • Plate Scale: 0.04 arcsec/pixel
  • Nominal Operating Temperature: -83C
  • Dark Current: ~9 e-/hr/pix (median) [Revised May 2019. See WFC3 IHB, Table 5.1]
  • Readnoise: 3.1 e-
  • Full Well: 63,000 -- 72,000 e- [See WFC3 IHB, Table 5.1]
  • Gain: 1.52 - 1.56 e-/ADU
  • Instrument Throughput: UVIS filters


  • Components: 1Kx1K Teledyne HgCdTe FPA, MBE grown, substrate removed
  • Wavelength Range: 800 to 1700 nm
  • Total Field of View: 123 x 136 arcsec (rectangular)
  • Pixel format: 1024x1024 (1014x1014 active)
  • Pixel Size: 18 microns
  • Plate Scale: 0.13 arcsec/pixel
  • Nominal Operating Temperature: 145 K
  • Dark Current: 0.048 e-/sec/pix (median) [See WFC3 IHB, Table 5.1]
  • 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]
  • Gain: 2.5 e-/ADU
  • Instrument Throughput: IR filters

Instrument Testing

WFC3 has undergone several iterations of fully integrated instrument testing. This testing took place at Goddard Space Flight Center (GSFC). During thermal vacuum (TV) testing, reference file data are collected and the instrument is characterized and calibrated. The first two TV sessions took place in the winter of 2004 and spring of 2007. TV3 testing is scheduled for early spring of 2008. The links below connect to pages giving the results from the various TV campaigns.

(Up to date calibration information is located in Howard Bushouse's Calibration Plan webpage. This page contains links to the science calibration test plan, SMS spreadsheets, and other associated documentation.)

TV3 Results

Spring 2008. This testing exercised both UVIS and IR flight detectors, and was used to collect data for the initial reference files.

TV3 testing took place in February and March of 2008. Both flight detectors were installed in the instrument.


TV2 Results

Summer 2007. TV2 was performed with backup UVIS and IR detectors in place.

TV2 testing used a backup UVIS detector (build 2), and a backup IR detector (FPA129).


TV1 Results

Winter 2004. WFC3's first TV test was performed with the flight UVIS detector and a backup IR detector in place.

TV1 testing used the flight UVIS detector (build 1), but a backup IR detector (FPA64).

Below is a list of ISRs supplying TV1 test results.


Mini-Ambient Results

Just prior to TV1 testing, WFC3 underwent a limited set of tests with the instrument under ambient conditions. We referred to this testing as "mini-ambient".

UVIS Detector Oddities found during mini-ambient

This page gives examples of WFC3 detector characteristics noted prior to ambient testing. Examples of each type of behavior, along with links to any relevent ISRs, are provided below. 


TV Supporting Documents

Castle ETC, V1.8 (18.8 MB)
Castle ETC Manual (1.1MB)
OS (Castle) Input Spreadsheet (23KB)
SMS Input Spreadsheet, Version 2 (Nov '06) (38KB) 
Old versions of input spreadsheets.

Image Quality

Image quality analysis of the UVIS channel during ground testing show 90-92% of the flux from a 250nm point source falling within a diameter of 0.35 arcsec. This decreases with increasing source wavelength, to 85-86% for a 810nm point source.

UVIS Flight Detector

  • ISR 2005-10: WFC3 UVIS PSF Evaluation in Thermal-Vacuum Test #1
    G. Harting 03 Mar 2005

  • ISR 2004-08: Preliminary WFC3 UVIS PSF Evaluation
    G. Hartig 24 May 2004

Additional Performance Information


LAST UPDATED: 06/17/2019

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