Draw a labelled ray dig to show the image formation in a refracting telescope at normal adjustment. Why should the diameter of the objective of the telescope be large? Give 2 reasons.
Dear Student,
The telescope is said to be in normal adjustment when the final image is formed at infinity.
The reason because the diameter of the objective of the telescope be large -
1. Larger diameter telescope lens/mirror collect more light & are therefore capable of seeing dimmer objects. This is extremely important because most astronomical objects are very dim & can't be seen with smaller objective lenses/mirrors.
2. In addition to collecting more light, larger objectives are capable of resolving finer detail as well. By increasing the diameter of objective lens we can increase the range of the telescope, as the diameter of lens increases, the area covered by the lens also increases ie; the lens is able to focus on a large area thereby helping us to view the object better.
Regards
The telescope is said to be in normal adjustment when the final image is formed at infinity.
The reason because the diameter of the objective of the telescope be large -
1. Larger diameter telescope lens/mirror collect more light & are therefore capable of seeing dimmer objects. This is extremely important because most astronomical objects are very dim & can't be seen with smaller objective lenses/mirrors.
2. In addition to collecting more light, larger objectives are capable of resolving finer detail as well. By increasing the diameter of objective lens we can increase the range of the telescope, as the diameter of lens increases, the area covered by the lens also increases ie; the lens is able to focus on a large area thereby helping us to view the object better.
Regards