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Filters for solar observing


spaceboy
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Hi all

I have had much success in using my Lunt wedge with a #58 dark green filter on the sun and this only got better using the Baader solar continuum filter but I have read that facula are nearer the blue end so would a #49 dark blue filter improve these features or is there a similar dedicated filter all ready available ?

Would I be right in saying these features are best viewed in CaK ?

I also read that CaK isn't the most visual friendly wavelength even in dedicated scopes so is it worth my time perusing using filters ??

I have an 80A filter I will try once I get clear skies at the same time the sun is in a favourable position in the sky.

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I've played around with the few colour filters I've got and haven't noticed any great improvement other than when mixing a 80a blue and yellow to get the desired green affect. I used this set up with the Baader Solar Film for quite a while until I had saved enough to buy the Herschel and a secondhand Continuum. If I recall correctly, I do remember using a deep red filter with the Baader Solar Film and it certainly darkened the umbrae but wasn't really of use to make detailed observations. I really don't know anything about CaK but I've read many times that by the time you reach adulthood the eyes have lost the UV sensitivity and make visual observing of the CaK region almost impossible. Imaging, however, is an entirely different game. Sorry I couldn't help more.

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Yep its correct that CaK is not associated with rich viewing.  The Ca-K wavelength is at the edge of the visible light spectrum for human eyes, so for many people visual observing will be difficult, which is why they are geared towards astro photography.  I personally would really like to have a look into one but not sure if the chance will come along. 

but I have read that facula are nearer the blue end so would a #49 dark blue filter improve these features or is there a similar dedicated filter all ready available ?

Blue will assist in seeing faculae further from the limb than normal (Wratten # 47 is recommended for this).  Light green will enhance granulation & faculae (Wratten # 56 / 58 / 61).  The red end will increase contrast of knots and radial streaks in the penumbrae of sunspots (Wratten # 29 / 25A / 23A).   

From J.Jenkins again :)

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