Zoom eyepieces offer a compelling proposition to the visual observer. They provide real convenience – a single eyepiece covering a range of magnifications means a more streamlined kit and less fumbling in the dark – but they’ve historically had a reputation for optical compromises.
Over time the gap between a good fixed focal length eyepiece and a quality yet affordable zoom has been growing smaller. I’ve long used a Celestron 8-24mm and other eyepieces of the same design as part of my travel and grab and go observing setups. For the past several years I’ve been using the Svbony SV135 7-21mm zoom with a range of telescopes and found it has some advantages over the older designs.
