WFC Parallel EPER
Old coefficients are given in Table 2 of ACS ISR 2005-03. Below is the table with the new coefficients. MJD limits are defined such that MJD1 <= MJD < MJD2. The discontinuities are an educated guess based on known temperature changes and observed CTE trends. Their fits are shown in the plots to follow.
| MJD1 | MJD2 | n | c | p | Notes about MJD2 |
|---|---|---|---|---|---|
| 52335 | 53552 | 8.086x10-5 | 2.329x10-6 | -5.799x10-1 | Aft shroud temperature test |
| 53552 | 53918 | -5.520x10-4 | 2.569x10-6 | -5.616x10-1 | -77C to -81C; Switched to Side-2 |
| 53918 | 58849 | -6.947x10-4 | 2.739x10-6 | -5.532x10-1 | A distant future |
CTE vs Signal
Here are the fit residuals:
Here is the legend:
CTE vs Time
"Problematic" point is as re-defined by M. Mutchler during SM4 SMOV (2009; private communication) based on initial prediction in ACS-R Multi-Parameter Optimization Constraints (ACS TIR 2008-04).
Here are the fit residuals:
Here is the legend:
These are no longer good fits
Least-square straight lines do not fit so well anymore without having to break the data into separate segments as above.
Here are the fit residuals for the plot above:
Predictions using fits from ACS ISR 2005-03 do not fit post-SM4 data well.
Here are the fit residuals for the plot above:
