| | 3 | |
| | 4 | To determine the date ranges we should use the A/B mode darks, I processed OTA67 darks over the entire range of usable dates. All darks were selected to be 30s exposures that were either the 2nd or 7th of that night's sequence. I then measured the slopes as done previously, and used this slope as the proxy to determine the dark quality and which dark is the best fit. The following plot summarizes this data, along with a set of bars indicating the current time range of various active darks. |
| | 5 | |
| | 6 | The red points show the slopes allowing detselect to choose the current appropriate model. As we have no new models valid for data prior to 2010-01-23 (as the headers prior to that date have a different keyword for the detector temperature), these data are only fit with their default models. The large slopes and scatter in this data suggest new darks would be useful for this older data. |
| | 7 | |
| | 8 | For data taken after 2011-05-01, the A-mode dark is the current model, and has been previously proven to match the data better than previous models. This data is included for completeness. |
| | 9 | |
| | 10 | The intermediate period (2010-01-23 to 2011-05-01) is currently fit with det_id 845, which is the "average" dark that was constructed without knowledge of the A and B modes. This data does separate reasonably well into the two modes, with the B-mode dark minimizing the slopes for those dates that seem to be in that mode. The A-mode dark does not appear to be a significant improvement over det_id 845, making the choice of which dark to use for these dates unclear. |
| | 11 | |
| | 12 | Before constructing any new darks, I am going to register a set of B-mode darks that have date ranges that cover only that data that is clearly in the B-mode, such that slope_B < slope_845. |
