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Knowledgebase: IRAC
What is the first-frame effect and why should I worry about it?
Posted by Seppo Laine on 21 November 2008 11:56 AM
The bias level varies depending on the type of the previous observation and the time delay between the current and the previous observation. The variation is highest for very short delays. Therefore, in-place frame repeats suffer most from this effect. Also, the effect is most noticeable in sensitive, long frames, and not of much concern in 2-second frames. Therefore we recommend that for the most accurate image reduction and calibration of your data you should avoid frame repeats. We have a first-frame effect corrector in the IRAC pipeline, but the corrections are not perfect for the worst first-frame effect cases.