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Baader Calcium K-Line

Finally Arrived

I ordered a Baader Calcium K-Line Filter to use with my awesome Baader Herschel Wedge and to bring you, even more, images of our solar universe. Unfortunately, the filter is on back order. Using the Baader Calcium filter should give me more interesting images of our sun.  This is the first time doing business with High Point and maybe the last as they don’t post current inventory so you never know what they have on hand ready to ship – too many other online vendors out here in internet land who has an honest showing of the items in stock.

I hope that the Baader Calcium K-Line Filter makes imaging the sun in Calcium accessible to me with my telescope and solar camera. Baader's offers an innovative double-stacked filter with very sophisticated coatings to produce a sharp 8nm wide bandpass, centered at 395nm. This bandpass provides great contrast and high-resolution imaging of supergranulation, flares, and other features that are prominent in CaK. The Baader Calcium filter will be used with my two telescopes of  127 and 80mm aperture both being refractors.

In addition to imaging the sun in CaK, the Baader K-Line filter opens up another exciting possibility - imaging Venus! The narrow bandpass @ 395nm enables us to see cloud structures, with results similar to the dedicated Baader Venus Filter.

This Baader K-Line Filter will be used just like any standard 1.25" thread-on eyepiece filter to be attached to my camera nose.  For my objective pre-filter, I will be using my  Baader Herschel Safety Wedge Solar Prism as the energy rejection filter (in place of the AstroSolar Photo Film). This will provide the absolute highest quality solar images possible in CaK.

About the Baader K-Line Filter

If you are thinking about buying a Baader Double Stacked Ca K-Line Filter over say the Daystar Calcium H filter, you are in luck. The Baader kline does an excellent job. I have owned and used this filter for a few years, and it is worth the price. However, once the Solar imaging bug bites you, you may like I did go ahead and pony up and buy the Daystar version. 

Baader ships the K-line to you as a standard 1.25" thread-on eyepiece filter that is easily attached to your telescope eyepiece for projection imaging, or if you are lucky directly to a camera's nosepiece for prime-focus/imaging. 


  • The filter must be used with a solar pre-filter to reduce the heat energy that reaches the filter - recommend that you get yourself a front mount white light filter, or if you have like I do the Baader Solar wedge, mount the filter after the wedge.  
  • Not suitable for visual use.

Pros: Simple to use and a lot of fun for imaging.

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