Photometric Data
Solar Indices Explained
| Sunspot Area | The total area of all sunspots on the solar disk, computed from the red (672.3nm) images, in millionths of the solar hemisphere. |
| Sunspot Deficit | The change, in millionths of the solar hemisphere, of the total solar irradiance (TSI) due to sunspots. This value is computed from the measured contrast of all sunspots seen in the red (672.3nm) image. |
| Facular Excess | The total area of all faculae on the Ca II K-line (393.4nm) image, in millionths of the solar hemisphere. |
| Ca II K-line Excess (Photometric Facular Index) |
The change, in millionths, of the total solar irradiance (TSI) due to faculae. This value is computed from a model and the sizes and locations of the bright areas seen in the K-line image. |