I think it's the LaunchServices framework that throws away the #SkyView.
Here is a method that works: I don't know how to do this with Safari,
but with Mozilla you can use AppleScript. From the command line, the
following will work (one line)
osascript -e 'tell application "Mozilla" to OpenURL
"file:///Library/Documents/3.6man/xephem.html#SkyView"'
Maybe something similar will work with Safari, but I don't know the syntax.