I have been spending a bit of time admiring solar photos such as those from the Dutch open telescope and the like, and they all seem to use a H-Alpha filter
Can anybody suggest a good filter, that will fit my celestron 6 and is not to expensive.
These Ha filter units need an aperture stop to provide at least an f20 (or above) light cone to the filter. The resolution (bandwidth) of 1.2A approx is ideal for viewing prominences, but a little wide for detailed surface contrast.
A PST is cheaper.