> An alternative to the curved spider that I've seen uses straight
> legs, but arranged non-radially.
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> Optically, these vanes shouldn't give diffraction spikes, since
> they don't radiate from the optical centre. Like curved vanes,
> they smear the diffraction around more.
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> Disclaimer: I haven't tried it myself, but it made sense in the
> book.
Apart from not having *any* advantage ove a classic spider (it will have *exactly* the same amount of diffraction), this is mechanically the worst possible solution (frankly I wouldn't expect much better from "Mr. Popular Astronomy").
I still think that absolutely best design is one suggested by Texerau, with slightly offset vanes :
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Yes, it looks remarkably similar. But what a difference in performance! This is *much* stronger than even "standard" four vane, with radially positioned vanes (like most commercially made ones). Have all those different designs tensioned approximately the same and then try to move and twist the secondary holder. You'll be shocked by the difference !
Bratislav