Hi there guys my first on the forum, just venturing into phonescoping at the moment have a opticron hr 66 x27 fixed eyepiece and using a viking adapter with xperia xz2 compact. Looking to upgrade scope as its very old. Looking at ed/HD type but not sure on size of lens width from 50-80 but mm any opinions on all different sizes on the net, have looked at vanguard endeavour 80a but really not sure as others. Would be used for birding aswell.