Making of Solar Filter from Baader AstroSolar Film

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In my previous post, I mentioned my reasons for ordering the Baader AstroSolar film in preparation for photographing the transit of Venus. In this post, I will describe the process that I adopted for making a solar filter. The filter can be fitted to any D-SLR lens using a standard Z-PRO Cokin ND filter holder. My design choice was primarily dictated by the fact that I will be using my D-SLR with a telephoto zoom lens (most likely my Canon EF 70-300mm f/4.5-5.6 IS USM) instead of a telescope, and I already have the Z-PRO filter holder. The Baader film came with instructions on how to construct a Filter Cell for using any telescope; you could also follow their instructions to construct your own filter. I don’t think, from an image quality standpoint, that there is any fundamental difference between the two ways of mounting the filter in front of your lens. Their recommended way is suitable if you are using a telescope, or you don’t have a filter holder like one mentioned here.

The picture below shows all the material that you may need (I actually ended up using a blade too and didn’t use the gloves at all) to construct the filter. I was extra careful not to touch any part of the film with my figures. Things to note in the picture are two 4×6 size photo mat that I bought from Michaels, the AstroSolar film (unrolled slightly), and the Z-PRO Cokin filter holder on the top right.

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Gearing up: Received Baader AstroSolar film

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The last time I pointed my camera towards the Sun to photograph the 2009 Total Solar Eclipse, which is also a “once in a lifetime experience,” I had used a piece of a $9.00 Mylar Thermal Blanket instead of a proper solar filter in front of my lens. Well, that was not by choice but by chance as I was carrying a Mylar thermal blanket with me. Mylar blankets, which are made by vacuum depositing a very precise amount of pure aluminum vapor onto a very thin film substrate (Mylar), reflects upto 97% of radiated heat. This makes them very effective for preventing body heat from escaping. They are commonly used by campers as “thermal blankets” and also used in a lot of solar projects.

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