Quote:So I spose my question is what are the advantages to a larger focal length? Do I even know my focal length before testing with sun, being wrong to assume accuracy using a straight edge and calipers to measure depth at center? Will this glass really reflect light? I have read that coma is reduced with a larger f-ratio, that a smaller f-ratio will give a wider field of view and eyepieces can work to make up for a smaller focal length? To have a 36in focal length would be far more convenient for using/moving my telescope without help.