Barlow Lenses Explained

A Barlow lens increases the effective focal length of your telescope, allowing your existing eyepieces to produce higher magnification without purchasing additional eyepieces.

It's one of the most popular accessories for both beginners and experienced astronomers.

How Does a Barlow Lens Work?

The Barlow fits between your telescope and eyepiece.

Common options include:

  • 2x Barlow

  • 3x Barlow

  • 5x Barlow

For example:

A 20mm eyepiece used with a 2x Barlow performs like a 10mm eyepiece.

Benefits

  • Doubles or triples your eyepiece collection

  • Maintains comfortable eye relief

  • Excellent value for money

  • Ideal for planetary observing

Things to Consider

Higher magnification also magnifies atmospheric turbulence, so a Barlow performs best on nights with steady seeing conditions.

Using excessive magnification may result in softer images, particularly with smaller telescopes.

Our Advice

A quality 2x Barlow lens is often one of the first accessories we recommend. It offers excellent flexibility and allows you to get more from the eyepieces you already own.