Hi all, firstly I'm a complete beginner and I've just purchased a Sky-Watcher 200p Dobsonian scope. I've gone through the process of collimation following Astro-Baby's guide and the collimation pattern I see through my cheshire looks pretty good now - I'm seeing concentric circles with the centre spot on the Cheshire in the middle of the primary mirror ring. I'm noticing something a bit odd using the 25mm eyepiece that came with the scope however, the image seems to jump around moving my eye from exactly on-axis with the eyepiece to slightly off-axis. Additionally the image isn't hugely sharp but i'm not sure if I'm just expecting too much from a pretty basic eyepiece and scope? Does anyone know if an image appearing to shift around moving when moving your eye line at the eyepiece from on-axis to slightly off indicates that collimation is off or it's an issue with the eyepiece?
I hope that makes sense and someone might be able to help!