star test question

Can someone here suggest what abberations are present in this photo from website. Specifically why the in focus side has much more detailed cocentric lines than the outside focus. Thanks.


http://aberrator.astronomy.net/scopetest/html/refractor_80_6.html

The star test looks great to me especially compared to the star test that the achros did, inside focus being sharper,brighter means that the scope is undercorrected for spherical aberation, but this scope has very little of that no scope is perfect, but this certainly doesn't look significant to me.