Release Notes for ETC 25.2

New Features

Welcome to ETC 25.2. This version of the ETC implements a few small improvements, notably:


  • Improved column headers on spectroscopic mode results pages
  • A helpful exception is raised if a malformed filename is entered into “Other HST Spectra”


  • Nothing to report.


  • Improved text descriptions on the COS spectroscopic target acquisition results page


  • Nothing to report.


  • Corrected sensitivities for quad filters: An error was introduced into the computation of sensitivity and count rates for the UVIS quad filters when the two-chip calibration system was introduced into synphot, pysynphot, and the ETC. This error has been corrected in ETC 25.2, restoring the previous calibration for the quad filters. Changes for most quad filters are less than 2%. Count rates have now been reduced by greater percentages for the following filters: FQ232N (21%), FQ243N (18%), FQ889N (8%), FQ906N (4%), FQ924N (6%), and FQ937N (12%). For more information, see Deustua & Bajaj WFC3 ISR 2017-11.


  • The wording of various sections of the user’s guide has been improved for clarity.

Under the hood

  • Instrument data values and/or detector sensitivity values have been updated for all instruments

Resolved Issues


  • Each WFC3/UVIS quad filter (named F*Q) covers somewhat less than a quadrant of the UVIS FOV on a particular chip, 1 or 2. Even though the ETC will let the user select either chip, when only one is physically possible, the ETC will now compute the correct results, using the chip associated with the quad filter regardless of user input.

Known Issues

Please see the News and Known Issues page for known issues with this release.


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