What is the angular diameter ? What and how is the angle subtended by d at the earth ? What is angular size ? Alpha stands for what ? Ultimately plzzzzzz describe thw meaning of this two paragraphs
Dear Student
Angular Diameter:
The angular diameter or apparent size is an angularmeasurement describing how large a sphere or circle appears from a given point of view. In the vision sciences it is called the visual angle and in optics it is the angular aperture (of a lens).
![](https://s3mn.mnimgs.com/img/shared/ck-files/ck_5915b43962099.jpg)
If the diameter of the planet is d and the distance between the planet and the Earth is D then we can find out the angular diameter by
Angular Size:
Angular size refers to the objects apparent size as seen from an observer on Earth. For example the Moon has an angular size of approximately 30 arcminutes.
Alpha stand for the angular diameter which unit will be radian
Regards
Angular Diameter:
The angular diameter or apparent size is an angularmeasurement describing how large a sphere or circle appears from a given point of view. In the vision sciences it is called the visual angle and in optics it is the angular aperture (of a lens).
![](https://s3mn.mnimgs.com/img/shared/ck-files/ck_5915b43962099.jpg)
If the diameter of the planet is d and the distance between the planet and the Earth is D then we can find out the angular diameter by
Angular Size:
Angular size refers to the objects apparent size as seen from an observer on Earth. For example the Moon has an angular size of approximately 30 arcminutes.
Alpha stand for the angular diameter which unit will be radian
Regards