A telescope has a concave mirror with a curvature radius of 2000 mm.
To which distance from the vertex of the mirror is situated the image of a star ?
The mirror has a ray curvature of 2000 mm its focal distance f ' is 1000 mm. The image of a star is at 1000mm from the vertex of the mirror.
What is the dimension of the moon of which the visible diameter is 30 arc minutes ?
The moon has a visible diameter of 30 arc minutes, such that :
The image dimension in the focal plane is :
