Ha Hb and CaK Sun 27 Jan LT

[Maurice]

Hi

Attached are three images of the Sun in Ha, Hb & CaK wavelengths from a morning imaging session on the 27th Jan LT.

Each image is a stack of 11, 5 & 6 frames respectively.
Data selected & stacked with Autostakkert3! and processed with Astrosurface.

All frames here are 60% of original size & compressed.
100mm f/9 Skwatcher refractor + home built Spectroheliograph + ASI183MM camera

Seeing was fair, but deteriorated as the session progressed to below average by the time that CaK data were collected.

cheers
Maurice

[John W (John Wilkinson)]

Interesting comparison Maurice - the Ha seems to show detail the best.

Regards, John W.

[Stefan Buda]

Nice going Maurice - any idea why there is no brightness correlation between the Ha and Hb but there is good correlation between the Ha and Cak?
One would expect it the other way around. Probably something to do with the different excitation energies required for the two hydrogen emissions lines.

[Maurice]

Originally Posted by John W

Interesting comparison Maurice - the Ha seems to show detail the best.

Regards, John W.

Thanks John.
I agree that Ha seems the more dynamic of the observable wavelengths.

Originally Posted by Stefan Buda

Nice going Maurice - any idea why there is no brightness correlation between the Ha and Hb but there is good correlation between the Ha and Cak?
One would expect it the other way around. Probably something to do with the different excitation energies required for the two hydrogen emissions lines.

Hi Stefan

Interesting question...and one that I do not have an answer to...but..

When looking at the CaIIK1 line, the physical distribution of that species looks to be at about 500km into the Chromosphere, and not much more or less.
Ha on the other hand is between about 1250 and 1700km into the Chromosphere from the Photosphere, with the peak that I observe at around 1500Km in.
These are very defined positions within the region.
From what I have read so far (& I could be wrong) the distribution of Hb on the other hand seems to be throughout the Chromosphere all the way to the Photosphere (Ken...anyone..please jump in & correct me here...).

Perhaps this has something to do with the appearance. Its not that the bright areas in Ha & Ca are not bright in Hb, its that everything else also seems relatively bright...but I don't know...I'm new to this solar stuff...

cheers
Maurice

[Stefan Buda]

Thanks Maurice,

I was only wondering because both the Ha and Hb emissions are produced by the same hydrogen atoms but obviously at different locations.

Anyway, have you tried making an arty image by combining them as RGB?