White Light Solar Filter

I mentioned to the San Antonio Astronomical Association that if anyone had any of the filter film, I would like to make a solar filter. This last week, my friend Keith Little gave me a gift. He is making several solar filters and had purchased a sheet of Baader filter film. He was able to cut me a 4 inch diameter disc.

I obtained a couple sheets of foam core board for this project. I cut two pieces about 3 inches bigger in diameter than my scope’s opening, and then a couple pieces that would make up a stack of rim pieces. I cut an opening 3-1/2 inches in diameter and situated as close to my secondary mirror as I could make it without the secondary blocking the circle cut.

I taped the piece of Baader film to one of the large discs across the cut-out. Then I taped the second disk to the first and the rim pieces to these two pieces.

I used a piece of malleable wire to create a safety device to assure me that the filter cover cannot blow off my scope while I am looking at the sun.

All together this project took about 2 hours and it works great. If we ever start having sun spots again, I’ll be able to look at them now!