# how to connect two eyepieces together with the x3 Barlow lens

how to connect two eyepieces together with the x3 Barlow lens

I have 10mm,25mm, and x3 Barlow. Is there any way to connect them together to archive the maximum magnification of 105mm?

• Jan 15, 2018 at 13:06

You will get the maximum magnification by using the 10mm eyepiece with the barlow lens. You cannot connect 2 eyepieces in the way you suggest, but even if you could add the 10 and the 25 to get a 35mm, that would give lower magnification, as I explained in a previous answer.

A Barlow lens doesn't multiply the focal length of your eyepiece, it multiplies the focal length of your telescope. Example:

Let's use a telescope of 1000mm focal length. 8" f/5 Newtonian, for example. And you have a 10mm and 25mm Eyepiece and a 3x barlow.

Then the barlow turns these 1000mm into 1000 x 3 = 3000mm focal length.

The magnification is always: FL telescope / FL eyepiece. That means, with the barlow, you have 3000 / 10 = 300x magnification or 3000 / 25 = 120 x magnification. Without barlow it's 100x (10mm) and 40x (25mm)

An eyepiece is a magnification lense. You can put two eyepieces on top of each other. You just won't see anything useful with that. Lens systems are carefully designed to result in an eyepiece that works.

Eyepieces with a bigger focal length give smaller magnification.