A close up of Sunspot 3190 from yesterday (11.45 AM).
The earth would fit comfortably within the central umbra of this sunspot, where it is darkest and coolest (~3500C). Other parts of the protosphere (imaged here) which lie outside the umbra and penumbra are hotter and typically around 6000 degrees Celcius.
(the sun’s corona, in contrast, which lies further from the sun than the protosphere and chromosphere, is around 1-2 million degrees Celsius).
In the central umbra of this sunspot the magnetic field lines are vertical to the sun’s surface. The strong magnetic field that is highly focussed in these sunspots inhibits the upward flux of hot new gas from the sun’s interior, causing them to be cooler and darker than the surrounding area.
The umbra is surrounded by the hotter penumbra. A series of earths could fit along the surrounding penumbra of this large sunspot. Here in the surrounding penumbra the magnetic field lines are sub-horizontal and they work to shape/deform the convection cells (the granulation) that lies outside the penumbra and covers the solar surface. These horizontal field lines deform the equidimensional convection cells into the characteristic streaky/filamentous shapes within the penumbra.
The formation of a penumbra is quite rapid (about 5 hours to develop around a growing umbra). The penumbra is the feature that defines sunspots and it differentiates sunspots from pores (the smaller black spots to the left and right which are small/immature at this point and so lack penumbra).
A marker of “good seeing” with the telescope is the filamentous structure of the penumbra. This streaky texture is somewhat blurred in these 2 images as I was imaging near midday and convecting hot air was rising off the concrete driveway underfoot and driving air-currents in front of the telescope, despite the fact that I was actively hosing the concrete whilst the AVI video capture was underway.
In order to maximise resolution, it’s normally best to image solar system objects or DSO’s (deep space objects) when they are high in the sky, to avoid imaging through long sections of turbulent atmosphere. However from what I read, solar imaging is actually better at the start and end of the day (and typically best at the start of the day) when the sun is lower and the atmosphere near the ground is cooler. So my next attempt to gain better resolution will be to image around 8-9am rather than close to midday.