The telescope has a lens diameter of 10 cm and a focal length of 1 m. Eyepieces with what focal lengths it makes sense to use with this telescope: 5 mm; 15 mm; 25 mm; 10 cm?
15 mm and 25 mm. The angular resolution of the telescope objective is 1.4 ‘- This means that an increase of more than 86 times will not lead to an improvement in image detail, but will lead to a drop in image brightness. Magnification less than equilateral (12.5x) will result in loss of light collected by the lens. Therefore, from the specified set of eyepieces, only eyepieces with focal lengths of 15 and 25 mm give a suitable magnification.
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