Quick answer
A 2x barlow lens sits between your telescope and eyepiece to double magnification, letting you see finer detail on planets and the Moon without buying new eyepieces.
Why use a barlow lens instead of a new eyepiece?
A barlow lens is a tube with internal optics that effectively doubles the focal length of your telescope. This means any eyepiece you already own can deliver twice the magnification. For example, a 20mm eyepiece that normally gives 50x magnification becomes a 10mm eyepiece giving 100x. It is a less expensive way of expanding an existing set of eyepieces and giving more scope to what can be seen.
The main trade-off is that higher magnification also magnifies atmospheric turbulence and any vibration in the mount. On very unsteady nights, the image may appear soft or wobbly. A barlow lens works best when the air is calm and your tripod is stable.
How to use a barlow lens in 3 steps
- 1. Remove the eyepiece and insert the barlow lens: Take the eyepiece out of the telescope's focuser or diagonal. Slide the barlow lens into the focuser barrel until it fits snugly. Tighten the thumbscrew just enough to hold it firmly without overtightening. Common mistake: inserting the barlow first and then the eyepiece is correct, but inserting the eyepiece directly into the barlow without the barlow seated in the focuser can cause it to fall out.
- 2. Insert your eyepiece into the barlow lens: Place the eyepiece into the open end of the barlow lens. The eyepiece barrel should slide in fully. Secure it with the barlow's own thumbscrew. You now have a combined assembly that effectively doubles the eyepiece's magnification. Common mistake: using an eyepiece with a barrel size that does not match the barlow (e.g., a 1.25" eyepiece in a 1" barlow) will not fit and can damage the threads or optics.
- 3. Focus and observe: Look through the eyepiece and slowly turn the telescope's focus knob until the image appears sharp. You may need more fine-tuning than usual because the higher magnification makes focus more critical. Start with a bright target like the Moon or Jupiter. Common mistake: expecting a perfectly sharp image on a turbulent night. If the image shimmers or blurs, wait for a calmer moment or reduce magnification by removing the barlow lens.
Product fact
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Danubia 2x Barlow Lens for 1" Astro Telescope Eyepieces: The Danubia 2x Barlow Lens fits 1" astro telescope eyepieces and increases magnification by two. This makes it easier to spot detail on the surface of planets or in the solar system without buying a separate high-power eyepiece.
Danubia 2x Barlow Lens for 1" Astro Telescope Eyepieces
