Apparent Field of View

[gooseholla]

Hello,

If the moon is half a degree, and my 20mm gives a field of view of 1 degree, what does Apparent Field of View = 52 degrees mean?

[miguel87]

the moon being 0.5 degrees relates to the entire celestial sphere and can be broken down into minutes and seconds, i.e. 360 degrees is from the north star through the southern cross and all the way round to where you started.

FOV (field of view) refers to the angle which your pupil must move across your eye to view the whole apparent image. Human vision is limited at around 150 degrees. Eyepieces generally top out at about 90, 20 is considered very small.

[MjrTom]

The width of the view you see through the eyepiece