One small patch of good seeing for a CH4-18nm but poor for the rest including the RGB, there's always tomorrow which is one of the best attributes of this hobby!
Regards, Phil
Thanks very much all, if anyone is interested in buying a CH4 filter I would recommend at least 18nm wide unless you have a +16" mirror and are prepaid to wait for excellent seeing. I have just ordered one from ZWO for my 14" and at $99 it seems a fairly good deal it is 20nm wide. My previous ones were $650US 18nm & $395AU 8nm which is rather excessive I think.
Re the 20" Fullum Tech mirror. They are becoming more popular because of their thermal equilibrium properties, my addition of a central hole in the base for air flow (Bird's invention) is the unconventional bit and well worth the extra work. I mostly leave the mirror fan running even when imaging as so far I have not noticed any adverse effects, near perfect seeing may be the only way I can see if there are any micro vibrations.
