The Dutch Observatory

April 5, 2020 on 6:50 pm | In Sun | Comments Off

One Active Region….three days …. in three wavelengths.
Three days in the evolution of AR2759.

Shown are close ups of AR2759 on April 2nd, April 3rd, and April 4th in Ha, 540nm and CaK.  The horizontal comparison shows the evolution over the three days shown in the images, whereas the vertical comparison shows the difference we see in different wavelengths.  On the first day when the area measured 20 millionths and was a D-class area, the 540nm and CaK image are enlarged a bit, but one can see the faint faculae in 540nm how they pretty much follow the patterns of the plages in the other wavelengths. Interesting to see the penumbra in the 540nm image on the 2nd at the southern outside of the two larger spots, whereas the center spot is devoid of any penumbra. Also pretty obvious how much the spots have deteriorated on the last day. And lastly, it shows how my CaK scope’s optics are affected by corrosion in need for resurfacing.