allowed me to get the refractor mounted and balanced for some quick looks at Venus, Jupiter andAlmach. The latter double star gave a spectacular view at 104X, showing great orange & blue colors. The APO refractor presented great separation and beautiful star images. ...
The best narrowband solar imaging refractor lens is a long focal-ratio achromatic doublet. And no matter what the glass or figure is, its at the mercy (limit) of the seeing conditions. Achromatic_vs_APO_Longitudinal_Spherochromatism.jpg Very best, This is a really interesting set of ...