How long should your flats be?
Enter full-well capacity, target fill percentage, and your measured ADU at 1 second to get a recommended flat exposure.
Inputs
Classic range: 30–50% of full well
From a 1-second test flat
Results
Adjust the inputs to see results.
Target ADU = full well × (fill% / 100); exposure = target ADU / ADU at 1s, clamped to 0.01–30 seconds.
All formulas verified by automated tests.