I'm in the process of buying a second-hand daystar solar filter (0.6A T-scanner) and it comes with a 3" ERF filter. Basically, the ERF (energy rejection filter) sits at the front of the scope over the lens while the main h-alpha filter is in the back in the focuser. They look like this:
www.astroshot.com/Solar/Daystar-Filter.jpg
H-alpha filter at the top and ERF in an aluminium cell at the bottom.
The cell holds the filter and allows it to fit over the front of the scope.
However, the cell that's on offer is not the right size to fit over the front of my scope. So I'm thinking about making my own and I'm wondering if anyone has tried anything like this before. If so, any suggestions?
I can get a piece of aluminium sheeting and cut it into a circular shape - that should be relatively easy to do, I think.
The size of the disc of aluminium would be the same as the outside diameter of the telescope.
The, I could cut a hole in it slightly smaller than the filter.
The filter could then be attached in some way to the aluminium disc.
The problem I see though is how to attach this 2D circular piece of aluminium to fit snugly & safely over the front of the telescope.
Any suggestions would be appreciated.
Cheers,
Michael.
  