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Hi Allan
I have a WO 80mm f7 ED triplet APO and a Vixen ED102mm f9 APO - both show blue haloes around the brightest field stars on long exposure photographs. With my Pentax DSLR, the WO 80mm ED triplet Apo shows appreciable coma at the edges.
However, the naked eye views are superb in both 'scopes.
Some time ago I looked at the 1st Qtr moon through my ED102S f9 and a Tak FS102 f8 using the same Tak LE 7.5mm eyepiece. I first looked through my Vixen and the moon looked razor sharp and nice and white. I then looked through my friends Tak FS102 and in comparison, the Vixen's image now appeared somewhat yellow and not quite as sharp.
So, it seems there are Apo's and there are Apo's. I suspect the Tak 90mm would be superior in terms of colour correction compared to the WO 80mm ED triplet.
A difficult choice to make.
Cheers
Dennis
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