I made myself a solar filter last saturday for my 90mm refractor. Couldnt resist looking at the sun, but I became completely confused about focussing the eyepiece. Tried different eyepieces, but all I saw was a lovely white disc which looked pretty well the same wherever the EP was focussed. Is there a technique to focussing? as there is no detail to see? I ended up waiting for night and then focussing on a star - and that's where the EP stays!!
With a white-light filter, all you'll see in sunspots and the sun is pretty devoid of them at the moment. Make sure you find the EDGE/LIMB of the sun and use that to focus, so you get as crisp an edge as possible.
Yep, what Mike said. If you want to see details like flares and prominences, one of the best solutions is the Coronado PST. This is a dedicated Ha solar telescope. There are full aperture Ha filters available for your scope, but be prepared to pay upwards of $3000!! For the transit of Mercury on the 9th of november, white light is probably better anyways.
I just wanted to see how best to focus in on Mercury, as I guess it's going to be tiny compared to the Sun
