To test to 40mm Ostara plossl eyepiece , I used a Visionary Telesto 114mm Newtonian telescope to view the Moon and Jupiter.
Conditions were not favourable for the test, due to near by light pollution and a brisk wind. With all the light pollution, I feared lots of internal reflection from the 40mm plossl. To my surprise, there was none evident. This helped give a crisp and clear view. The focal length of the eyepiece gave 25x power when used with the Visionary Telesto 114. The Moon took up around 1/3 of the wide field of view.
Having such a low power eyepiece gave very good edge of field sharpness , with virtually no ghosting. Overall, the eyepiece gave remarkable results for such a low priced item. Despite the Telesto getting mixed reviews, this test proved that even the lowest spec telescopes can give great results with the addition of an Eyepiece upgrade.
The low power eyepiece gave superb views of the Mountain,s valleys and craters. This included Clavius and all the mini craters within.
Turning to Jupiter. At just 25x you are not going to see much detail. But the two main cloud belts were clear to see, and the 4 satellites were pin point dots of light.
Only one issue was the lack of an eye cup. I would estimate that eye relief is approx 25mm. Without an eye cup to rest on (no spectacles used) I needed to move my head forwards and backwards till I hit the sweet spot . I found this took a few seconds to master. However, if you are a telescope novice that does,nt understand fully how eye relief works, this could be a problem.
The long eye relief , on the plus side mean,t that I could easily view the Moon without having to shut one eye. Also the wide 28mm clear aperture is ideal for basic digiscoping.