A second day of sun 14 April 2023

[Averton]

There was a small amount of sun this morning after some initial clouds cleared and before they rolled back in. Unfortunately by the time it had cleared (about 11am local time) the seeing was averaging 3.5 arc seconds with a standard deviation of 1.0. This was a pity as it was a really interesting disk with many proms, filaments and active regions. It wasn't really worth setting up much equipment so we just did a two panel Ha mosaic of the full disk, and a full disk in 393nm. While we were there we popped in a 1.9x barlow and did an four panel 393nm mosaic as well. We couldn't make a small version of the mosaic to post here.

[John W]

Good images Peter and Clare despite conditions. There are still some interesting features to be seen. Regards, John W.

[Averton]

Thanks John :)

[Dennis]

Lovely series Clare and Peter, the 393 nm (is that CaK?) resolves some amazing detail in the active regions, the solar granulation and faculae for such a relatively small aperture.:thumbsup:

You folks are a fair dinkum imaging factory, such a prodigious and high quality output.:)

Cheers

Dennis

[Averton]

Thanks Dennis.
Yes the wavelength of Calcium K is 393.4nm. However, we don't refer to our images as CaK as that is normally used to refer to images taken with a etalon based filter which is sub nanometer narrow. The filter we use is just a coating filter of 3nm bandwidth so is too wide to obtain genuine CaK images. Our filter is made by Antlia. Baader make a similar filter and call it K-line. At 3nm the photosphere still shows through, but we have found it does enhance the plain photosphere images that you get with a solar continuum filter at 540nm. It particularly enhances the faculae.

Having two of us certainly helps with the processing of our image data. We just enjoy our astronomy and particularly solar imaging :)

[Dennis]

Thanks for those details.:)

Cheers

Dennis

[Averton]

:thumbsup::thumbsup: