Measurements of Ca K filters with Sol'Ex spectrograph

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christian viladrich
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Measurements of Ca K filters with Sol'Ex spectrograph

Post by christian viladrich »

Hello,
Here are the first interesting measurements of Ca K filters I made with the Sol'Ex spectrograph.

The center wavelength (CWL), FWHM and bandwidth at 10 % transmission are reliable to +/-0.1 A.

Here is the profile of the Barr Associated Ca K filter. This is a 2-cavity filter:
http://astrosurf.com/viladrich/astro/in ... ay2021.jpg

The profile of the Alluxa Ca K filter :
http://astrosurf.com/viladrich/astro/in ... ne2021.jpg
This is a 3-cavity filter. The measurements made with the Sol'Ex are very close to manufacturer measurements.

I am still at the beginning of the learning curve. I hope to improve the accuracy of the overall shape of the tranmission profile.

It seems possible to measure 1 A FWHM filters with the Sol'Ex. Ha filters would be a different game.


Christian Viladrich
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MalVeauX
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Re: Measurements of Ca K filters with Sol'Ex spectrograph

Post by MalVeauX »

Interesting Christian,

So neither exceed 50%~60% transmission respectively approximately at 3934A? Interesting that both filters do have high transmission according to the measurements at some point, but not at the K II line?

I wonder what Lunt's looks like?

Very best,


christian viladrich
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Re: Measurements of Ca K filters with Sol'Ex spectrograph

Post by christian viladrich »

Hello Marty,
Just a clarification, I plotted the "normalized" transmission, which means the peak transmission is set to 100%. Measuring the actual peak transmission is still on the to-do list (probably arround 90% for Alluxa and arround 30% for Barr).

Ca K is at 3933.7 A. Tilting Alluxa filter shifts the bandpass to Ca II K. It's kind of funny to see this with the spectro.


Christian Viladrich
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http://planetary-astronomy.com/
Editor of "Solar Astronomy"
http://www.astronomiesolaire.com/
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Re: Measurements of Ca K filters with Sol'Ex spectrograph

Post by marktownley »

Interesting, thanks Christian!


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