Is the higher the number of millimeters on a tellescope lens weaker or stronger than a lower number of millimeters.
For example, if i have a 6.7mm and a 9.7mm lens, which one would have greater magnification?
2007-06-24 14:44:51 · 6 answers · asked by Horcrux 3 in Science & Mathematics ➔ Astronomy & Space
You're using the wrong terminology here. These are not "lenses" but "eyepieces". Eyepieces are made up of lenses, but they are not called "lenses"...that's camera terminology.
When used in a particular telescope, the eyepiece with the shorter focal length, e.g. 6.7 mm, will give a higher magnification than the eyepiece with the longer focal length, e.g. 9.7 mm. That's because magnification is calculated by dividing the focal length of the telescope by the focal length of the eyepiece. A telescope with 1200 mm focal length would yield 1200/9.7=124x with the 9.7 mm eyepiece, and 1200/6.7=179x with the 6.7 mm eyepiece.
2007-06-24 16:28:30 · answer #1 · answered by GeoffG 7 · 1⤊ 0⤋
The shorter focal length eyepiece is the higher magnification one. So 6.7 has a higher magnification than a 9.7. Magnification is calculated as focal length of objective divided by focal length of eyepiece. You didn't say what the focal length of your objective lens is, but let us assume it is 700mm. The 700/6.7=104 power and 700/9.7=72 power. If you don't know the focal length of your objective, and you have a refractor or simple Newtonian reflector, you can get an approximate idea by just measuring the length of the the telescope with a ruler. Remember to express it in millimeters, because the calculation will only give you the correct magnification if both focal lengths are measured in the same units.
2007-06-24 14:58:53 · answer #2 · answered by campbelp2002 7 · 5⤊ 0⤋
The smaller the number in mm, the higher the magnification. The number is the focal length of the eyepiece.
However, the magnification varies from telescope to telescope because in a telescope, magnification = (telescope focal length)/(eyepiece focal length)
2007-06-24 21:34:39 · answer #3 · answered by minuteblue 6 · 1⤊ 0⤋
A reflective telescope will derive its 'power' form the diameter of its primary mirror. That diameter is usually given in both inches and millimeters. From the millimeter measurement of that lens times ten you get the focal length of your telescope. The power is calculated by dividing the focal length of the telescope by the focal length (in millimeters) of your eyepiece. (they all have that number stamped on the side) so for a 12 inch telescope, you get a focal length of around 3000mm if you use a 30mm eyepiece you'll get around 100x (powers). Theoretically you could use any eyepiece with any telescope attaining any power that you want but reality is quite different. For practical purposes the maximum power attainable by a telescope is calculated by multiplying the diameter of the main mirror (in inches) times 60. So a 3 1/2 inch telescope will yield under the BEST (and I do mean ideal) conditions around 210x and that means that the smallest eyepiece you can use would be 5mm. but you'd end up with a very dimmed and blurry view. In reality your telescope will give you the best images at half it's maximum yield. With the mentioned 3 1/2 in. telescope you'll get a great picture with a 12mm eyepiece.
2007-06-24 15:41:11 · answer #4 · answered by ΛLΞX Q 5 · 1⤊ 2⤋
Which Telescope
2016-10-06 03:38:43 · answer #5 · answered by ? 4 · 0⤊ 0⤋
the smaller the number the greater the magnification.
I never heard of a 6.7! Only a 6!
4mm is the smallest made
2007-06-24 16:59:24 · answer #6 · answered by Anonymous · 1⤊ 0⤋