it is a mistake to exaggerate the importance of magnifying power when you buy a telescope.you cannot increase the useful magnifying power indefinitely by changing eyepieces.
starlight must pass through Earth's atmosphere to reach waiting telesscopes on the ground. Disturbances in the air cause blurry images. Seeing refers to atmospheric conditions which affect how sharp a telescope image is. if the air is quiet then the seeing is good and star shine with a steady light. if the air is turbulent then the seeing is bad and the star twinkle madly.
the practical limit of useful magnification for any telescope is about fifty times its objective diameter in inches. Higher power will serve to magnify any blurring in the image due to diffraction or bad seeing. It can't reveal any finear details.