2007-05-07 10:49:12 · 3 answers · asked by plunkphillip 1 in Science & Mathematics ➔ Astronomy & Space
The short answer is, a barlow increases the magnification.
You see, in a telescope, the magnification = (focal length of the telescope)/(focal length of the eyepiece)
A telescope eyepiece that has a focal length of 12.5mm offers more magnification for the same telescope, than a telescope eyepiece with a 25mm focal length.
But, if I use the 25mm eyepiece with a 2x barlow, I will get the same magnification that the 12.5mm eyepiece provides, because it is equivalent to reducing the focal length of the eyepiece by 2, since 25/2 = 12.5
The advantage of doing this, rather than using the 12.5mm eyepiece is, it's easier to look through the 25mm eyepiece as the lens on it is much larger. It offers more eye relief.
2007-05-08 19:43:34 · answer #1 · answered by minuteblue 6 · 0⤊ 0⤋
It increases the focal length of the telescope thus magnifying the image. It is like inserting a doubler on your camera lens. If you have a 50mm camera lens and put in a 2x doubler you now have a 100mm lens. It isn't a free lunch though. It does decrease the image quality.
2007-05-07 11:03:01 · answer #2 · answered by DaveSFV 7 · 1⤊ 0⤋
All you need to know here:
2007-05-07 11:02:27 · answer #3 · answered by Anonymous · 1⤊ 0⤋