For anyone with thoughts or experience?
I've long liked the idea of a Coronado but I simply cant justify the expense. So what I was wondering was about a cheaper conceptual alternative.
I have both a glass filter and Baader films for looking at the sun. They work as expected. They are good but the sun still doesn't show much definition beyond sunspots. And as anyone will know you don't see the remarkable images you get with narrowband hydrogen alpha images.
Now the glass filter is coloured yellow but the film filter is white suggesting it is letting through all wavelengths.
The obvious question this raises is can one simply put a hydrogen alpha filter into an eyepiece and get something approaching the Coronado images?? while of course using the Baader film as an upfront filter to maintain safety.
Now I know that you will get a big reduction in light - but with my 8" Cassegrain I would think there is more than enough light I think to compensate for say a 2 nm band pass filter (I might need a shroud and dark sensitivity adjustment time but that's ok). Alternatively maybe a deep red glass filter might give a lot of improvement.
With this in mind I looked around a little. Interestingly most glass filters don't come with absorption characteristics plots and most of the common filters aren't in the right range. The exception did seem to be Baader but they don't have a deep red glass filter.
But they do seem to have a number of hydrogen alpha filters with varying band pass width for CCD cameras at least
http://www.baader-planetarium.de/sektion/s43d/s43d.htm
The main ones seem to offer 7nm and 35 nm bands.
Any comments on this idea?? The filters cost a bit but are still a lot cheaper than a full blown coranado.