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I know what you mean about eye placement Don. I find that nearing the edge of field, eye placement needs to be fairly "extreme" to minimise CA in the XWs, i.e. quite a long way off-axis and closer to the lens (the eyecup needs to be readjusted compared with ideal position for on-axis viewing). Don't get me wrong, I'm not knocking the XW, in fact it's my preferred choice for all types of viewing, but newcomers to the hobby need to understand that no eyepiece is perfect, not even the best ones.
It may surprise some that I find the 13mm Stratus in my 2" barlow better with regard to off-axis CA than the 7mm XW. The barlowed Stratus has CA under control over most of its FOV (all but the last few degrees) with much gentler purple-green fringing that does not need much shift in eye placement to minimise. This is with a very long and very good barlow though where the 13mm sees a much slower light cone (f/11) compared with the 7mm w/o barlow (f/5). A fairer comparison would be with the 14mm XW in the same barlow. But I don't have the 14mm XW anymore and when I did I never compared.
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