monocular question

[zamboxl]

hey guys if a monocular is 2x36 does that mean it magnifies things 2 times?? if so whats the 36 for?

 

[candr44]

36 is the size of the front lens in milimeters. The bigger the better for letting in light and giving you a bright image.

The magnification power to front lens size will also affect the image quality. There is a formula for selecting optics for use in day or night. Off hand I don't remember what it is but the general rule is to have the aperature of the eye end no less than 7 milimeters at full magnification if you intend to use it in dark places. 7 milimeters is the size of a fully dialated pupil.

 

[zamboxl]

so how do i know how wide is the eye end, where does it say how big it is?

 

[candr44]

You use the formula that I can't remember to find the eye size. You should find it on the internet. I believe Mead telescopes and binoculars or Celestron has a guide on selecting binoculars that has the formula. It's a simple formula but I haven't used it or seen it in years so it's long forgotten.