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Hubble Space Telescope
Old CGI ETC Limitations and Known Problems

  1. Calculations are done only for the brightest pixel.
  2. The saturation limits have not been updated. The CGI-ETC uses the old Cycle 7 values (145,000 e-, 145,000 e-, and 185,000 e- for NIC1, NIC2 and NIC3 respectively, instead of 116,000 e-, 111,000 e-, and 178,000 e- for Cycles 11+).
  3. Although the CGI-ETC results agree with those of the APT-ETC for the large majority of cases, there are a few exceptions for which the CGI-ETC gives wrong answers. Known cases are:
    • NIC2 + F212N
    • NIC2 + F215N
    • NIC2 + F216N
    • NIC3 + F212N
    when the HST standard spectrum of G191B2B is selected.