Some of the imagery in the Voynich, in particular You are not allowed to view links.
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I agree that it does look alot like medieval star charts but I dont see how it has a connection to Halley's Comet
Almost every illuminated medieval manuscript with astronomical info included pictures of eclipses, and some of them also comets, so it's quite possible there is something in the VMS that represents a comet, but I don't know if it would be a specific one.