How do I actually mount my Barlow lens in the telescope?

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	How do I actually mount my Barlow lens in the telescope?

Answer A Barlow lens is a negative focal length lens that is used to increase the effective focal length of a telescope and therefore the magnification.

A typical Barlow has a two-element achromatic lens at the end of a barrel that is 1-1/4” in diameter. This end is designed to fit into an eyepiece drawtube on your telescope. Barlows usually are 2x, meaning they double your eyepiece magnification when used in the manner described below.

The opposite end of the Barlow is larger and has a setscrew. It has an opening that is 1-1/4” inside diameter to accept eyepieces.

To use the Barlow, stack it with the eyepiece. Start by removing your eyepiece from the eyepiece drawtube. (If you are using a star diagonal, remove the eyepiece from the star diagonal.)

Now insert the Barlow in place of the eyepiece. (If you are using a star diagonal, the Barlow may protrude somewhat from the diagonal, exposing more of the front chrome barrel of the Barlow. This won’t affect performance.) Secure the Barlow with the drawtube setscrew (or the diagonal’s setscrew).

Finally, put the eyepiece into the Barlow and secure it with the setscrew.

Article Details

Article ID:

2527

Created On:

Aug 23 2011 03:47 PM