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FOV


Guest zidder

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Hi Gary. I think you can do a practical test by timing the transit of a star from one side of the eye piece to the other. You'll need to pick a star close to the celestial equator. We rotate 1 degree in 4 minutes so you can calculate from there. 


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What eyepieces are you referring to Gary.


 


Do they at least have a brand name.


 


The only option I know of is the same as Allan explained.


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Guest zidder

What eyepieces are you referring to Gary.

 

Do they at least have a brand name.

 

The only option I know of is the same as Allan explained.

All they have is the size on them

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Measure the diameter of the eyepiece field stop in millimetres. That is the lens farthest from the eye.

Multiply it by 57.3 then divide that by the eyepiece focal length to get the apparent FOV in degrees.

AFOV=(Field Stop*57.3)/Focal Length

Edited by Tweedledee
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Guest zidder

Have done the calculations ( I think) results :


 


15mm = 57 deg


 


20mm = 48 deg


 


28mm = 55 deg


 


do these seem feasible ? 

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