Another session with this wonderful solar region. Today I tried to gain a bit of resolution by using a green filter instead of the red one. The seeing was good in red, but the lower wavelengths were a bit difficult. Nevertheless, some improvement is observable, when compared with the previous sessions.
200mm F/5 Newtonian, Full aperture Astrosolar filter, Baader Green CCD filter, ASI 174MM. Scope working at F/25 and F/35. Seeing 4-5/10 (in green), 6-7/10 (in red).
Also, some H-alpha images of this group, for now a comparison between two shots acquired at four hours from each other. Structural changes inside the group are observable, as is the apparent change in position, due to the rotation of the Sun.
An animation showing the activity of this region in H-alpha. The animation shows changes over 40 minutes starting at 11:03 U.T. Note the rotation of the Sun, as the limb gets lower in the frames. A few small flares occur during the image sequence. Note also the “grass in the wind” effect of the solar surface.
These two groups (AR 2673 and AR 2674), at the time I write this, are two-three days from re-emerging at the solar limb, after a two-week journey. The next free astro show is about to begin!
And something interesting that I’ve found after reprocessing the above animation: penumbral waves!!
More about the subject may be found here.
And a reprocessed animation, with some arrows pointing to the location of the waves in the penumbra of the two main spots in AR2673: