I have just half-completed a very scary summer project! The Hyperstar III lens assembly is a fantastic technological achievement which turns an ultra-slow f#10 Schmidt-Cassegrain into an ultra-fast f#2 Schmidt-Camera. There is a slight problem though with all that glass in the Hyperstar – thick lenses – and the edges of the lenses are frosted, not blackened. This means that if you wish to image a bright constellation star, you will unfortunately get some lens flaring. For non-bright constellation stars I rarely get any problem.
So – just as I did with the Hyperstar I, I took the whole lens assembly apart (scary) and then painted the edges of the lenses matt black (VERY scary!) they are now all sitting on my desk in the sunshine for the paint to thoroughly dry off. I use Revell colour Black Matt 9 – this is the paint used on Airfix kits. It is probably not the best paint to use – there is a proprietary paint you can get from the States that is made especially to paint the edges of lenses.
I will keep you informed of how things progress (or not) when I rebuild the Hyperstar III and take my first image with the modified lenses. Keep everything crossed for me 🙂