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The Cooke refractor I’m familiar with was very much ok, having used it many times. A beautiful thing with fine optics. As I recall it, despite being a 4.25” doublet at f/16 the residual colour errors were not objectionable - unlike some modern achro refractors.
That’s only a sample of 1.
The other refractor I used a lot was the Oddie at Mt Stromlo but that was not an amateur scope. Compared to say my Santel MK91, the Santel is optically better than the Oddie was.
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