Table 3
Activity thresholds for two types of observations according to the availability of images taken in hydra filter.
| Hydra | Hydra not | |
| Channels | available | available |
|
|
||
| R | (Hydra/NIR) ≥ 0.908 | (Orange/NIR) ≥ 0.794 |
| G | Orange | Orange |
| B | (Orange/Hydra) ≥ 0.893 | (Blue/Green) ≥ 0.922 |
Notes. The best detection of active regions was achieved using the images taken with orange, hydra, and NIR filters but because operational constrains, not all observing sequences include all filters. Therefore, another definition is introduced for a common observing sequence.
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