BRESSER 3x 1.25" achromatic Barlow lens

The magnification of your telescope can be tripled with the use of this BRESSER Barlow 3x 31.7 mm (1.25'') Achromatic Lens .

The magnification provided by a telescope is a function of the focal length of the eyepiece: the smaller it is, the greater the magnification. The increases are calculated like this:

Magnification factor = telescope focal length/eyepiece focal length

Suppose a telescope has a 150mm objective and 750mm focal length, then the 20mm eyepiece will provide: 750 / 20 = 37.5x magnification , while the 6mm eyepiece will provide: 750 / 6 = 125x magnification .

The factor used will always depend on the object to be observed:

• Eyepiece for searching or observing large nebulae : factor increase from 20 to 25
• Galaxies, the Moon and the Sun : factor increase from 50 to 80
• Details about the surface of the Moon and the planets : factor increase from 120 to 150
• Details on planets and binary stars : factor increase from 200 to 300

Before purchasing this product it is important to make sure that the magnifications are recommended for your telescope. For example, normally the maximum magnification allowed for a telescope is its objective multiplied by 2, for example, for a telescope with a 130 mm objective the maximum magnification will be 260, considering that its focal length is 750 mm you will not be able to use a superior eyepiece. at 9mm since 750/9= 83x magnification multiplied by 3 (Barlow 3) = 250x magnification, very close to the 260x allowed.