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Monday, June 4, 2012

DIY Solar Filter

With the Transit of Venus only 2 days away I thought I'd try build a solar filter. After looking around the net for inspiration I came up with a hybrid of things that I came across. I decided to try some welding glass (I think the glass I got is equivalent to 10 stops) and rescued a plastic yoghurt container from the recycling.

Camera settings: (Spot Metering, other settings default on Xperia Arc)

No Glass

One sheet of glass handheld over camera lens

One of the sites I came across said to paint the container black (Spray Paint) but I didn't have any and thought I'd use that magical material - Tape, Electrical tape in this case (I've used it to regrip a tennis raquet before) it also hopefully will add some structural integrity to the filter.

Yoghurt container with a hole cut out the back (the inner rim happened to be an excellent fit for my Lenses) some tape and welding glass (I've only used the one piece but will take the second one and tape along when I try to get some photos of Venus and the Sun just in case it needs more)

Place the glass inside the lip of the container. This turned out pretty well the shape of the container grips the glass. Here I applied one layer of tape to the outside of the container.

Next I applied one layer of tape to the inside of the container to stop light reflection (hopefully)

More tape, little bit fiddly to do the inside

Inside and outside done. I ran the tape around the top lip and bottom to help secure the vertical pieces of tape for the inside ans the straps started just at the base, wrapped through the hole, up the sides the over the top lip.

The last piece, I placed the welding glass back in the top lip. Then decided on how to fill in the gaps... more tape will do it! :)

The finished product, 2 - 3 layers of tape around the glass to help stop light coming through the tape.

The hole at the bottom of the container fits pretty snug, good enough that it can support the weight of the filter lens thing and does not inhibit my ability to use the zoom on the lens.

I've tried one shot of a down light in the kitchen, camera can focus just fine, but a tripod will be necessary to get the most out of it.

So with any luck this Solar Filter which cost around $5 all up ($1.60 welding glass (double if I use the other one), some tape I had already, a used yoghurt container and around 30min)

If this works I'll post the results after the show!

I also scored myself 2 pairs of Eclipse Glasses, these are a lot darker than the welding glass...

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