Argos (or Argus Panoptes) was the 100-eyed giant in Greek mythology.
While NASA Solar Dynamics Observatory (SDO) has significantly less than 100 eyes, seeing connections in the solar atmosphere through the many filters of SDO presents a number of interesting challenges. This visualization experiment illustrates a mechanism for highlighting these connections.
The wavelengths presented are: 617.3nm optical light from SDO/HMI. From SDO/AIA we have 170nm (pink), then 160nm (green), 33.5nm (blue), 30.4nm (orange), 21.1nm (violet), 19.3nm (bronze), 17.1nm (gold), 13.1nm (aqua) and 9.4nm (green).
We've locked the camera to rotate the view of the Sun so each wedge-shaped wavelength filter passes over a region of the Sun. As the features pass from one wavelength to the next, we can see dramatic differences in solar structures that appear in different wavelengths.
- Filaments extending off the limb of the Sun which are bright in 30.4 nanometers, appear dark in many other wavelengths.
- Sunspots which appear dark in optical wavelengths, are festooned with glowing ribbons in ultraviolet wavelengths.
- Small flares, invisible in optical wavelengths, are bright ribbons in ultraviolet wavelengths.
- If we compare the visible light limb of the Sun with the 170 nanometer filter on the left, with the visible light limb and the 9.4 nanometer filter on the right, we see that the 'edge' is at different heights. This effect is due to the different amounts of absorption, and emission, of the solar atmosphere in ultraviolet light.
- In far ultraviolet light, the photosphere is dark since the black-body spectrum at a temperature of 5700 Kelvin emits very little light in this wavelength.
The movie opens with a full-disk view of the Sun in visible wavelengths. Then the filters are applied to small pie-shaped wedges of the Sun, starting with 170nm (pink), then 170nm (green), 33.5nm (blue), 30.4nm (orange), 21.1nm (violet), 19.3nm (bronze), 17.1nm (gold), 13.1nm (aqua) and 9.4nm (green). We let the set of filters sweep around the solar disk and then zoom and rotate the camera to rotate with the filters as the solar image is rotate underneath.
Video and caption: NASA Solar Dynamics Observatory